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RIVERSIDE TEXTBOOKS
IN EDUCATION
EDITED BY ELLWOOD P. CUBBERLEY
PROFESSOR OF EDUCATION
LELAND STANFORD JUNIOR UNIVERSITY
DIVISION OF SECONDARY EDUCATION
UNDER THE EDITORIAL DIRECTION
OF ALEXANDER INGLIS
PROFESSOR OF EDUCATION
HARVARD UNIVERSITY
THE MEASUREMENT
OF INTELLIGENCE
AN EXPLANATION OF AND A
COMPLETE GUIDE FOR THE USE OF THE
STANFORD REVISION AND EXTENSION OF
_The Binet-Simon Intelligence Scale_
BY
LEWIS M. TERMAN
PROFESSOR OF EDUCATION
LELAND STANFORD JUNIOR UNIVERSITY
[Illustration]
HOUGHTON MIFFLIN COMPANY
BOSTON NEW YORK CHICAGO SAN FRANCISCO
The Riverside Press Cambridge
COPYRIGHT, 1916, BY LEWIS M. TERMAN
ALL RIGHTS RESERVED
The Riverside Press
CAMBRIDGE · MASSACHUSETTS
PRINTED IN THE U.S.A.
To the Memory
OF
ALFRED BINET
PATIENT RESEARCHER, CREATIVE THINKER, UNPRETENTIOUS SCHOLAR;
INSPIRING AND FRUITFUL DEVOTEE
OF
INDUCTIVE AND DYNAMIC
PSYCHOLOGY
EDITOR'S INTRODUCTION
The present volume appeals to the editor of this series as one of the
most significant books, viewed from the standpoint of the future of our
educational theory and practice, that has been issued in years. Not only
does the volume set forth, in language so simple that the layman can
easily understand, the large importance for public education of a
careful measurement of the intelligence of children, but it also
describes the tests which are to be given and the entire procedure of
giving them. In a clear and easy style the author sets forth scientific
facts of far-reaching educational importance, facts which it has cost
him, his students, and many other scientific workers, years of
painstaking labor to accumulate.
Only very recently, practically only within the past half-dozen years,
have scientific workers begun to appreciate fully the importance of
intelligence tests as a guide to educational procedure, and up to the
present we have been able to make but little use of such tests in our
schools. The conception in itself has been new, and the testing
procedure has been more or less unrefined and technical. The following
somewhat popular presentation of the idea and of the methods involved,
itself based on a scientific monograph which the author is publishing
elsewhere, serves for the first time to set forth in simple language the
technical details of giving such intelligence tests.
The educational significance of the results to be obtained from
careful measurements of the intelligence of children can hardly be
overestimated. Questions relating to the choice of studies, vocational
guidance, schoolroom procedure, the grading of pupils, promotional
schemes, the study of the retardation of children in the schools,
juvenile delinquency, and the proper handling of subnormals on the
one hand and gifted children on the other,--all alike acquire new
meaning and significance when viewed in the light of the measurement
of intelligence as outlined in this volume. As a guide to the
interpretation of the results of other forms of investigation relating
to the work, progress, and needs of children, intelligence tests form a
very valuable aid. More than all other forms of data combined, such
tests give the necessary information from which a pupil's possibilities
of future mental growth can be foretold, and upon which his further
education can be most profitably directed.
The publication of this revision and extension of the original
Binet-Simon scale for measuring intelligence, with the closer adaptation
of it to American conditions and needs, should mark a distinct step in
advance in our educational procedure. It means the perfection of another
and a very important measuring stick for evaluating educational
practices, and in particular for diagnosing individual possibilities and
needs. Just now the method is new, and its use somewhat limited, but it
is the confident prediction of many students of the subject that, before
long, intelligence tests will become as much a matter of necessary
routine in schoolroom procedure as a blood-count now is in physical
diagnosis. That our schoolroom methods will in turn become much more
intelligent, and that all classes of children, but especially the gifted
and the slow, will profit by such intellectual diagnosis, there can be
but little question.
That any parent or teacher, without training, can give these tests, the
author in no way contends. However, the observations of Dr. Kohs, cited
in Chapter VII, as well as the experience of the author and others who
have given courses in intelligence testing to teachers, alike indicate
that sufficient skill to enable teachers and school principals to give
such tests intelligently is not especially difficult to acquire. This
being the case it may be hoped that the requisite training to enable
them to handle these tests may be included, very soon, as a part of the
necessary pedagogical equipment of those who aspire to administrative
positions in our public and private schools.
Besides being of special importance to school officers and to students
of education in colleges and normal schools, this volume can confidently
be recommended to physicians and social workers, and to teachers and
parents interested in intelligence measurements, as at once the simplest
and the best explanation of the newly-evolved intelligence tests, which
has so far appeared in print.
ELLWOOD P. CUBBERLEY.
PREFACE
The constant and growing use of the Binet-Simon intelligence scale in
public schools, institutions for defectives, reform schools, juvenile
courts, and police courts is sufficient evidence of the intrinsic
worth of the method. It is generally recognized, however, that the
serviceableness of the scale has hitherto been seriously limited, both
by the lack of a sufficiently detailed guide and by a number of
recognized imperfections in the scale itself. The Stanford revision and
extension has been worked out for the purpose of correcting as many as
possible of these imperfections, and it is here presented with a rather
minute description of the method as a whole and of the individual tests.
The aim has been to present the explanations and instructions so clearly
and in such an untechnical form as to make the book of use, not only to
the psychologist, but also to the rank and file of teachers, physicians,
and social workers. More particularly, it is designed as a text for use
in normal schools, colleges, and teachers' reading-circles.
While the use of the intelligence scale for research purposes and for
accurate diagnosis will of necessity always be restricted to those who
have had extensive training in experimental psychology, the author
believes that the time has come when its wider use for more general
purposes should be encouraged.
However, it cannot be too strongly emphasized that no one, whatever his
previous training may have been, can make proper use of the scale unless
he is willing to learn the method of procedure and scoring down to the
minutest detail. A general acquaintance with the nature of the
individual tests is by no means sufficient.
Perhaps the best way to learn the method will be to begin by studying
the book through, in order to gain a general acquaintance with the
tests; then, if possible, to observe a few examinations; and finally to
take up the procedure for detailed study in connection with practice
testing. Twenty or thirty tests, made with constant reference to the
procedure as described in Part II, should be sufficient to prepare the
teacher or physician to make profitable use of the scale.
The Stanford revision of the scale is the result of a number of
investigations, made possible by the coöperation of the author's
graduate students. Grateful acknowledgment is especially due to
Professor H. G. Childs, Miss Grace Lyman, Dr. George Ordahl, Dr. Louise
Ellison Ordahl, Miss Neva Galbreath, Mr. Wilford Talbert, Mr. J. Harold
Williams, and Mr. Herbert E. Knollin. Without their assistance this book
could not have been written.
STANFORD UNIVERSITY,
_April, 1916_.
CONTENTS
PART I. PROBLEMS AND RESULTS
CHAPTER I
THE USES OF INTELLIGENCE TESTS 3
Intelligence tests of retarded school children. Intelligence
tests of the feeble-minded. Intelligence tests of delinquents.
Intelligence tests of superior children. Intelligence tests as a
basis for grading. Intelligence tests for vocational fitness.
Other uses of intelligence tests.
CHAPTER II
SOURCES OF ERROR IN JUDGING INTELLIGENCE 22
Are intelligence tests superfluous? The necessity of standards.
The intelligence of retarded children usually overestimated. The
intelligence of superior children usually underestimated. Other
fallacies in the estimation of intelligence. Binet's
questionnaire on teachers' methods of judging intelligence.
Binet's experiment on how teachers test intelligence.
CHAPTER III
DESCRIPTION OF THE BINET-SIMON METHOD 36
Essential nature of the scale. How the scale was derived. List of
tests. How the scale is used. Special characteristics of the
Binet-Simon method. The use of age standards. The kind of mental
functions brought into play. Binet would test "general
intelligence." Binet's conception of general intelligence. Other
conceptions of intelligence. Guiding principles in choice and
arrangement of tests. Some avowed limitations of the Binet tests.
CHAPTER IV
NATURE OF THE STANFORD REVISION AND EXTENSION 51
Sources of data. Method of arriving at a revision. List of tests
in the Stanford revision and extension. Summary of changes.
Effects of the revision on the mental ages secured.
CHAPTER V
ANALYSIS OF ONE THOUSAND INTELLIGENCE QUOTIENTS 65
The distribution of intelligence. The validity of the
intelligence quotient. Sex differences. Intelligence of the
different social classes. The relation of the I Q to the quality
of the child's school work. The relation between I Q and grade
progress. Correlation between I Q and the teachers' estimates of
the children's intelligence. The validity of the individual
tests.
CHAPTER VI
THE SIGNIFICANCE OF VARIOUS INTELLIGENCE QUOTIENTS 78
Frequency of different degrees of intelligence. Classification of
intelligence quotients. Feeble-mindedness. Border-line cases.
Examples of border-line deficiency. Dull normals. Average
intelligence. Superior intelligence. Very superior intelligence.
Examples of very superior intelligence. Genius and "near" genius.
Is the I Q often misleading?
CHAPTER VII
RELIABILITY OF THE BINET-SIMON METHOD 105
General value of the method. Dependence of the scale's
reliability on the training of the examiner. Influence of the
subject's attitude. The influence of coaching. Reliability of
repeated tests. Influence of social and educational advantages.
PART II
GUIDE FOR THE USE OF THE STANFORD REVISION AND EXTENSION
CHAPTER VIII
GENERAL INSTRUCTIONS 121
Necessity of securing attention and effort. Quiet and seclusion.
Presence of others. Getting into _rapport_. Keeping the child
encouraged. The importance of tact. Personality of the examiner.
The avoidance of fatigue. Duration of the examination. Desirable
range of testing. Order of giving the tests. Coaxing to be
avoided. Adhering to formula. Scoring. Recording responses.
Scattering of successes. Supplementary considerations.
Alternative tests. Finding mental age. The use of the
intelligence quotient. How to find the I Q of adult subjects.
Material for use in testing.
CHAPTER IX
INSTRUCTIONS FOR YEAR III
1. Pointing to parts of the body 142
2. Naming familiar objects 143
3. Enumeration of objects in pictures 145
4. Giving sex 146
5. Giving the family name 147
6. Repeating six to seven syllables 149
Alternative test: Repeating three digits 150
CHAPTER X
INSTRUCTIONS FOR YEAR IV
1. Comparison of lines 151
2. Discrimination of forms 152
3. Counting four pennies 154
4. Copying a square 155
5. Comprehension, first degree 157
6. Repeating four digits 159
Alternative test: Repeating twelve to thirteen syllables 160
CHAPTER XI
INSTRUCTIONS FOR YEAR V
1. Comparison of weights 161
2. Naming colors 163
3. Æsthetic comparison 165
4. Giving definitions in terms of use 167
5. The game of patience 169
6. Three commissions 172
Alternative test: Giving age 173
CHAPTER XII
INSTRUCTIONS FOR YEAR VI
1. Distinguishing right and left 175
2. Finding omissions in pictures 178
3. Counting thirteen pennies 180
4. Comprehension, second degree 181
5. Naming four coins 184
6. Repeating sixteen to eighteen syllables 185
Alternative test: Forenoon and afternoon 187
CHAPTER XIII
INSTRUCTIONS FOR YEAR VII
1. Giving the number of fingers 189
2. Description of pictures 190
3. Repeating five digits 193
4. Tying a bow-knot 196
5. Giving differences from memory 199
6. Copying a diamond 204
Alternative test 1: Naming the days of the week 205
Alternative test 2: Repeating three digits reversed 207
CHAPTER XIV
INSTRUCTIONS FOR YEAR VIII
1. The ball-and-field test 210
2. Counting backwards from 20 to 1 213
3. Comprehension, third degree 215
4. Giving similarities, two things 217
5. Giving definitions superior to use 221
6. Vocabulary (20 definitions, 3600 words) 224
Alternative test 1: Naming six coins 231
Alternative test 2: Writing from dictation 231
CHAPTER XV
INSTRUCTIONS FOR YEAR IX
1. Giving the date 234
2. Arranging five weights 236
3. Making change 240
4. Repeating four digits reversed 242
5. Using three words in a sentence 242
6. Finding rhymes 248
Alternative test 1: Naming the months 251
Alternative test 2: Counting the value of stamps 252
CHAPTER XVI
INSTRUCTIONS FOR YEAR X
1. Vocabulary (30 definitions, 5400 words) 255
2. Detecting absurdities 255
3. Drawing designs from memory 260
4. Reading for eight memories 262
5. Comprehension, fourth degree 268
6. Naming sixty words 272
Alternative test 1: Repeating six digits 277
Alternative test 2: Repeating twenty to twenty-two syllables 277
Alternative test 3: Healy's Construction Puzzle A 278
CHAPTER XVII
INSTRUCTIONS FOR YEAR XII
1. Vocabulary (40 definitions, 7200 words) 281
2. Defining abstract words 281
3. The ball-and-field test (superior plan) 286
4. Dissected sentences 286
5. Interpretation of fables (score 4) 290
6. Repeating five digits reversed 301
7. Interpretation of pictures 302
8. Giving similarities, three things 306
CHAPTER XVIII
INSTRUCTIONS FOR YEAR XIV
1. Vocabulary (50 definitions, 9000 words) 310
2. Induction test: finding a rule 310
3. Giving differences between a president and a king 313
4. Problem questions 315
5. Arithmetical reasoning 319
6. Reversing hands of a clock 321
Alternative test: Repeating seven digits 322
CHAPTER XIX
INSTRUCTIONS FOR "AVERAGE ADULT"
1. Vocabulary (65 definitions, 11,700 words) 324
2. Interpretation of fables (score 8) 324
3. Differences between abstract terms 324
4. Problem of the enclosed boxes 327
5. Repeating six digits reversed 329
6. Using a code 330
Alternative test 1: Repeating twenty-eight syllables 332
Alternative test 2: Comprehension of physical relations 333
CHAPTER XX
INSTRUCTIONS FOR "SUPERIOR ADULT"
1. Vocabulary (75 definitions, 13,500 words) 338
2. Binet's paper-cutting test 338
3. Repeating eight digits 340
4. Repeating thought of passage 340
5. Repeating seven digits reversed 345
6. Ingenuity test 345
SELECTED REFERENCES 349
INDEX 359
FIGURES AND DIAGRAMS
1. Distribution of Mental Ages of 62 Normal Adults 55
2. Distribution of I Q's of 905 Unselected Children, 5-14 Years
of Age 66
3. Median I Q of 457 Boys and 448 Girls, for the Ages 5-14 Years 69
4. Diamond drawn by R. W.; Age 13-10; Mental Age 7-6 82
5. Writing from Dictation. R. M., Age 15; Mental Age 9 83
6. Ball and Field Test. I. M., Age 14-2; Mental Age 9 84
7. Diamond drawn by A. W. 85
8. Drawing Designs from Memory. H. S., Age 11; Mental Age 8-3 86
9. Ball and Field Test. S. F., Age 17; Mental Age 11-6 88
10. Writing from Dictation. C. P., Age 10-2; Mental Age 7-11 90
11. Ball and Field Test. M. P., Age 14; Mental Age 10-8 91
12. Ball and Field Test. R. G., Age 13-5; Mental Age 10-6 93
13. Ball and Field Test. E. B., Age 7-9; I Q 130 98
14. Ball and Field Test. F. McA., Age 10-3; Mental Age 14-6 100
15. Drawing Designs from Memory. E. M., Age 6-11; Mental Age 10,
I Q 145 101
16. Ball and Field Test. B. F., Age 7-8; Mental Age 12-4; I Q 160 102
17. Healy and Fernald Construction Puzzle 279
THE MEASUREMENT OF INTELLIGENCE
PART I
PROBLEMS AND RESULTS
THE MEASUREMENT OF INTELLIGENCE
CHAPTER I
THE USES OF INTELLIGENCE TESTS
INTELLIGENCE TESTS OF RETARDED SCHOOL CHILDREN. Numerous studies of the
age-grade progress of school children have afforded convincing evidence
of the magnitude and seriousness of the retardation problem. Statistics
collected in hundreds of cities in the United States show that between a
third and a half of the school children fail to progress through the
grades at the expected rate; that from 10 to 15 per cent are retarded
two years or more; and that from 5 to 8 per cent are retarded at least
three years. More than 10 per cent of the $400,000,000 annually expended
in the United States for school instruction is devoted to re-teaching
children what they have already been taught but have failed to learn.
The first efforts at reform which resulted from these findings were
based on the supposition that the evils which had been discovered could
be remedied by the individualizing of instruction, by improved methods
of promotion, by increased attention to children's health, and by other
reforms in school administration. Although reforms along these lines
have been productive of much good, they have nevertheless been in a
measure disappointing. The trouble was, they were too often based upon
the assumption that under the right conditions all children would be
equally, or almost equally, capable of making satisfactory school
progress. Psychological studies of school children by means of
standardized intelligence tests have shown that this supposition is not
in accord with the facts. It has been found that children do not fall
into two well-defined groups, the "feeble-minded" and the "normal."
Instead, there are many grades of intelligence, ranging from idiocy on
the one hand to genius on the other. Among those classed as normal, vast
individual differences have been found to exist in original mental
endowment, differences which affect profoundly the capacity to profit
from school instruction.
We are beginning to realize that the school must take into account, more
seriously than it has yet done, the existence and significance of these
differences in endowment. Instead of wasting energy in the vain attempt
to hold mentally slow and defective children up to a level of progress
which is normal to the average child, it will be wiser to take account of
the inequalities of children in original endowment and to differentiate
the course of study in such a way that each child will be allowed to
progress at the rate which is normal to him, whether that rate be rapid
or slow.
While we cannot hold all children to the same standard of school
progress, we can at least prevent the kind of retardation which involves
failure and the repetition of a school grade. It is well enough
recognized that children do not enter with very much zest upon school
work in which they have once failed. Failure crushes self-confidence and
destroys the spirit of work. It is a sad fact that a large proportion of
children in the schools are acquiring the habit of failure. The remedy,
of course, is to measure out the work for each child in proportion to
his mental ability.
Before an engineer constructs a railroad bridge or trestle, he studies
the materials to be used, and learns by means of tests exactly the
amount of strain per unit of size his materials will be able to
withstand. He does not work empirically, and count upon patching up the
mistakes which may later appear under the stress of actual use. The
educational engineer should emulate this example. Tests and forethought
must take the place of failure and patchwork. Our efforts have been too
long directed by "trial and error." It is time to leave off guessing and
to acquire a scientific knowledge of the material with which we have to
deal. When instruction must be repeated, it means that the school, as
well as the pupil, has failed.
Every child who fails in his school work or is in danger of failing
should be given a mental examination. The examination takes less than
one hour, and the result will contribute more to a real understanding of
the case than anything else that could be done. It is necessary to
determine whether a given child is unsuccessful in school because of
poor native ability, or because of poor instruction, lack of interest,
or some other removable cause.
It is not sufficient to establish any number of special classes, if they
are to be made the dumping-ground for all kinds of troublesome
cases--the feeble-minded, the physically defective, the merely backward,
the truants, the incorrigibles, etc. Without scientific diagnosis and
classification of these children the educational work of the special
class must blunder along in the dark. In such diagnosis and
classification our main reliance must always be in mental tests,
properly used and properly interpreted.
INTELLIGENCE TESTS OF THE FEEBLE-MINDED. Thus far intelligence tests
have found their chief application in the identification and grading of
the feeble-minded. Their value for this purpose is twofold. In the first
place, it is necessary to ascertain the degree of defect before it is
possible to decide intelligently upon either the content or the method
of instruction suited to the training of the backward child. In the
second place, intelligence tests are rapidly extending our conception of
"feeble-mindedness" to include milder degrees of defect than have
generally been associated with this term. The earlier methods of
diagnosis caused a majority of the higher grade defectives to be
overlooked. Previous to the development of psychological methods the
low-grade moron was about as high a type of defective as most physicians
or even psychologists were able to identify as feeble-minded.
Wherever intelligence tests have been made in any considerable number in
the schools, they have shown that not far from 2 per cent of the
children enrolled have a grade of intelligence which, however long they
live, will never develop beyond the level which is normal to the average
child of 11 or 12 years. The large majority of these belong to the moron
grade; that is, their mental development will stop somewhere between the
7-year and 12-year level of intelligence, more often between 9 and 12.
The more we learn about such children, the clearer it becomes that they
must be looked upon as real defectives. They may be able to drag
along to the fourth, fifth, or sixth grades, but even by the age of
16 or 18 years they are never able to cope successfully with the more
abstract and difficult parts of the common-school course of study. They
may master a certain amount of rote learning, such as that involved in
reading and in the manipulation of number combinations but they cannot
be taught to meet new conditions effectively or to think, reason, and
judge as normal persons do.
It is safe to predict that in the near future intelligence tests will
bring tens of thousands of these high-grade defectives under the
surveillance and protection of society. This will ultimately result in
curtailing the reproduction of feeble-mindedness and in the elimination
of an enormous amount of crime, pauperism, and industrial inefficiency.
It is hardly necessary to emphasize that the high-grade cases, of the
type now so frequently overlooked, are precisely the ones whose
guardianship it is most important for the State to assume.
INTELLIGENCE TESTS OF DELINQUENTS. One of the most important facts
brought to light by the use of intelligence tests is the frequent
association of delinquency and mental deficiency. Although it has long
been recognized that the proportion of feeble-mindedness among
offenders is rather large, the real amount has, until recently, been
underestimated even by the most competent students of criminology.
The criminologists have been accustomed to give more attention to the
physical than to the mental correlates of crime. Thus, Lombroso and
his followers subjected thousands of criminals to observation and
measurement with regard to such physical traits as size and shape of the
skull, bilateral asymmetries, anomalies of the ear, eye, nose, palate,
teeth, hands, fingers, hair, dermal sensitivity, etc. The search was for
physical "stigmata" characteristic of the "criminal type."
Although such studies performed an important service in creating a
scientific interest in criminology, the theories of Lombroso have been
wholly discredited by the results of intelligence tests. Such tests have
demonstrated, beyond any possibility of doubt, that the most important
trait of at least 25 per cent of our criminals is mental weakness. The
physical abnormalities which have been found so common among prisoners
are not the stigmata of criminality, but the physical accompaniments of
feeble-mindedness. They have no diagnostic significance except in so far
as they are indications of mental deficiency. Without exception, every
study which has been made of the intelligence level of delinquents has
furnished convincing testimony as to the close relation existing between
mental weakness and moral abnormality. Some of these findings are as
follows:--
Miss Renz tested 100 girls of the Ohio State Reformatory and
reported 36 per cent as certainly feeble-minded. In every one of
these cases the commitment papers had given the pronouncement
"intellect sound."
Under the direction of Dr. Goddard the Binet tests were given to
100 juvenile court cases, chosen at random, in Newark, New
Jersey. Nearly half were classified as feeble-minded. One boy
17 years old had 9-year intelligence; another of 15½ had
8-year intelligence.
Of 56 delinquent girls 14 to 20 years of age tested by Hill and
Goddard, almost half belonged either to the 9- or the 10-year
level of intelligence.
Dr. G. G. Fernald's tests of 100 prisoners at the Massachusetts
State Reformatory showed that at least 25 per cent were
feeble-minded.
Of 1186 girls tested by Miss Dewson at the State Industrial
School for Girls at Lancaster, Pennsylvania, 28 per cent were
found to have subnormal intelligence.
Dr. Katherine Bement Davis's report on 1000 cases entered in the
Bedford Home for Women, New York, stated that there was no doubt
but that at least 157 were feeble-minded. Recently there has
been established at this institution one of the most important
research laboratories of the kind in the United States, with a
trained psychologist, Dr. Mabel Fernald, in charge.
Of 564 prostitutes investigated by Dr. Anna Dwyer in connection
with the Municipal Court of Chicago, only 3 per cent had gone
beyond the fifth grade in school. Mental tests were not made,
but from the data given it is reasonably certain that half or
more were feeble-minded.
Tests, by Dr. George Ordahl and Dr. Louise Ellison Ordahl, of
cases in the Geneva School for Girls, Geneva, Illinois, showed
that, on a conservative basis of classification, at least
18 per cent were feeble-minded. At the Joliet Prison, Illinois,
the same authors found 50 per cent of the female prisoners
feeble-minded, and 26 per cent of the male prisoners. At the St.
Charles School for Boys 26 per cent were feeble-minded.
Tests, by Dr. J. Harold Williams, of 150 delinquents in the
Whittier State School for Boys, Whittier, California, gave
28 per cent feeble-minded and 25 per cent at or near the
border-line. About 300 other juvenile delinquents tested by
Mr. Williams gave approximately the same figures. As a result of
these findings a research laboratory has been established at the
Whittier School, with Dr. Williams in charge. In the girls'
division of the Whittier School, Dr. Grace Fernald collected a
large amount of psychological data on more than 100 delinquent
girls. The findings of this investigation agree closely with
those of Dr. Williams for the boys.
At the State Reformatory, Jeffersonville, Indiana, Dr. von
Klein-Schmid, in an unusually thorough psychological study of
1000 young adult prisoners, finds the proportion of
feeble-mindedness not far from 50 per cent.
But it is needless to multiply statistics. Those given are but samples.
Tests are at present being made in most of the progressive prisons,
reform schools, and juvenile courts throughout the country, and while
there are minor discrepancies in regard to the actual percentage who are
feeble-minded, there is no investigator who denies the fearful rôle
played by mental deficiency in the production of vice, crime, and
delinquency.[1]
[1] See References at end of volume.
Heredity studies of "degenerate" families have confirmed, in a striking
way, the testimony secured by intelligence tests. Among the best known
of such families are the "Kallikaks," the "Jukes," the "Hill Folk," the
"Nams," the "Zeros," and the "Ishmaelites."
_The Kallikak family._ Martin Kallikak was a youthful soldier in
the Revolutionary War. At a tavern frequented by the militia he
met a feeble-minded girl, by whom he became the father of a
feeble-minded son. In 1912 there were 480 known direct
descendants of this temporary union. It is known that 36 of
these were illegitimates, that 33 were sexually immoral, that 24
were confirmed alcoholics, and that 8 kept houses of ill-fame.
The explanation of so much immorality will be obvious when it is
stated that of the 480 descendants, 143 were known to be
feeble-minded, and that many of the others were of questionable
mentality.
A few years after returning from the war this same Martin
Kallikak married a respectable girl of good family. From this
union 496 individuals have been traced in direct descent, and in
this branch of the family there were no illegitimate children,
no immoral women, and only one man who was sexually loose. There
were no criminals, no keepers of houses of ill-fame, and only
two confirmed alcoholics. Again the explanation is clear when it
is stated that this branch of the family did not contain a
single feeble-minded individual. It was made up of doctors,
lawyers, judges, educators, traders, and landholders.[2]
[2] H. H. Goddard: _The Kallikak Family_. (1914.) 141 pp.
_The Hill Folk._ The Hill Folk are a New England family of which
709 persons have been traced. Of the married women, 24 per cent
had given birth to illegitimate offspring, and 10 per cent were
prostitutes. Criminal tendencies were clearly shown in
24 members of the family, while alcoholism was still more
common. The proportion of feeble-minded was 48 per cent. It was
estimated that the Hill Folk have in the last sixty years cost
the State of Massachusetts, in charitable relief, care of
feeble-minded, epileptic, and insane, conviction and punishment
for crime, prostitution pauperism, etc., at least $500,000.[3]
[3] Danielson and Davenport: _The Hill Folk_. Eugenics Record Office,
Memoir No. 1. 1912. 56 pp.
The Nam family and the Jukes give equally dark pictures as
regards criminality, licentiousness, and alcoholism, and
although feeble-mindedness was not as fully investigated in
these families as in the Kallikaks and the Hill Folk, the
evidence is strong that it was a leading trait. The 784 Nams who
were traced included 187 alcoholics, 232 women and 199 men known
to be licentious, and 40 who became prisoners. It is estimated
that the Nams have already cost the State nearly $1,500,000.[4]
[4] Estabrook and Davenport: _The Nam Family_. Eugenics Record Office
Memoir No. 2. (1912). 85 pp.
Of 540 Jukes, practically one fifth were born out of wedlock, 37
were known to be syphilitic, 53 had been in the poorhouse, 76
had been sentenced to prison, and of 229 women of marriageable
age 128 were prostitutes. The economic damage inflicted upon the
State of New York by the Jukes in seventy-five years was
estimated at more than $1,300,000, to say nothing of diseases
and other evil influences which they helped to spread.[5]
[5] R. L. Dugdale: _The Jukes_. (Fourth edition, 1910.) 120 pp. G. P.
Putnam's Sons.
But why do the feeble-minded tend so strongly to become delinquent? The
answer may be stated in simple terms. Morality depends upon two things:
(a) the ability to foresee and to weigh the possible consequences for
self and others of different kinds of behavior; and (b) upon the
willingness and capacity to exercise self-restraint. That there are many
intelligent criminals is due to the fact that (a) may exist without
(b). On the other hand, (b) presupposes (a). In other words, not
all criminals are feeble-minded, but all feeble-minded are at least
potential criminals. That every feeble-minded woman is a potential
prostitute would hardly be disputed by any one. Moral judgment, like
business judgment, social judgment, or any other kind of higher thought
process, is a function of intelligence. Morality cannot flower and fruit
if intelligence remains infantile.
All of us in early childhood lacked moral responsibility. We were as
rank egoists as any criminal. Respect for the feelings, the property
rights, or any other kind of rights, of others had to be laboriously
acquired under the whip of discipline. But by degrees we learned that
only when instincts are curbed, and conduct is made to conform to
principles established formally or accepted tacitly by our neighbors,
does this become a livable world for any of us. Without the intelligence
to generalize the particular, to foresee distant consequences of present
acts, to weigh these foreseen consequences in the nice balance of
imagination, morality cannot be learned. When the adult body, with its
adult instincts, is coupled with the undeveloped intelligence and weak
inhibitory powers of a 10-year-old child, the only possible outcome,
except in those cases where constant guardianship is exercised by
relatives or friends, is some form of delinquency.
Considering the tremendous cost of vice and crime, which in all
probability amounts to not less than $500,000,000 per year in the United
States alone, it is evident that psychological testing has found here
one of its richest applications. Before offenders can be subjected
to rational treatment a mental diagnosis is necessary, and while
intelligence tests do not constitute a complete psychological diagnosis,
they are, nevertheless, its most indispensable part.
INTELLIGENCE TESTS OF SUPERIOR CHILDREN. The number of children with
very superior ability is approximately as great as the number of
feeble-minded. The future welfare of the country hinges, in no small
degree, upon the right education of these superior children. Whether
civilization moves on and up depends most on the advances made by
creative thinkers and leaders in science, politics, art, morality, and
religion. Moderate ability can follow, or imitate, but genius must show
the way.
Through the leveling influences of the educational lockstep such
children at present are often lost in the masses. It is a rare child who
is able to break this lockstep by extra promotions. Taking the country
over, the ratio of "accelerates" to "retardates" in the school is
approximately 1 to 10. Through the handicapping influences of poverty,
social neglect, physical defects, or educational maladjustments, many
potential leaders in science, art, government, and industry are denied
the opportunity of a normal development. The use we have made of
exceptional ability reminds one of the primitive methods of surface
mining. It is necessary to explore the nation's hidden resources of
intelligence. The common saying that "genius will out" is one of those
dangerous half-truths with which too many people rest content.
Psychological tests show that children of superior ability are very
likely to be misunderstood in school. The writer has tested more than a
hundred children who were as much above average intelligence as moron
defectives are below. The large majority of these were found located
below the school grade warranted by their intellectual level. One third
had failed to reap any advantage whatever, in terms of promotion, from
their very superior intelligence. Even genius languishes when kept
over-long at tasks that are too easy.
Our data show that teachers sometimes fail entirely to recognize
exceptional superiority in a pupil, and that the degree of such
superiority is rarely estimated with anything like the accuracy which is
possible to the psychologist after a one-hour examination. _B. F._, for
example, was a little over 7½ years old when tested. He was in the
third grade, and was therefore thought by his teacher to be accelerated
in school. This boy's intelligence, however, was found to be above the
12-year level. There is no doubt that his mental ability would have
enabled him, with a few months of individual instruction, to carry fifth
or even sixth-grade work as easily as third, and without injury to body
or mind. Nevertheless, the teacher and both the parents of this child
had found nothing remarkable about him. In reality he belongs to a grade
of genius not found oftener than once in several thousand cases.
Another illustration is that of a boy of 10½ years who tested at the
"average adult" level. He was doing superior work in the sixth grade,
but according to the testimony of the teacher had "no unusual ability."
It was ascertained from the parents that this boy, at an age when most
children are reading fairy stories, had a passion for standard medical
literature and textbooks in physical science. Yet, after more than a
year of daily contact with this young genius (who is a relative of
Meyerbeer, the composer), the teacher had discovered no symptoms of
unusual ability.[6]
[6] See p. 26 _ff._ for further illustrations of this kind.
Teachers should be better trained in detecting the signs of superior
ability. Every child who consistently gets high marks in his school work
with apparent ease should be given a mental examination, and if his
intelligence level warrants it he should either be given extra
promotions, or placed in a special class for superior children where
faster progress can be made. The latter is the better plan, because it
obviates the necessity of skipping grades; it permits rapid but
continuous progress.
The usual reluctance of teachers to give extra promotions probably rests
upon three factors: (1) mere inertia; (2) a natural unwillingness to
part with exceptionally satisfactory pupils; and (3) the traditional
belief that precocious children should be held back for fear of dire
physical or mental consequences.
In order to throw light on the question whether exceptionally bright
children are specially likely to be one-sided, nervous, delicate,
morally abnormal, socially unadaptable, or otherwise peculiar, the
writer has secured rather extensive information regarding 31 children
whose mental age was found by intelligence tests to be 25 per cent above
the actual age. This degree of intelligence is possessed by about
2 children out of 100, and is nearly as far above average intelligence
as high-grade feeble-mindedness is below. The supplementary information,
which was furnished in most cases by the teachers, may be summarized as
follows:--
1. _Ability special or general._ In the case of 20 out of 31 the
ability is decidedly general, and with 2 it is mainly general.
The talents of 5 are described as more or less special, but
only in one case is it remarkably so. Doubtful 4.
2. _Health._ 15 are said to be perfectly healthy; 13 have one or
more physical defects; 4 of the 13 are described as delicate;
4 have adenoids; 4 have eye-defects; 1 lisps; and 1 stutters.
These figures are about the same as one finds in any group of
ordinary children.
3. _Studiousness._ "Extremely studious," 15; "usually studious" or
"fairly studious," 11; "not particularly studious," 5; "lazy,"
0.
4. _Moral traits._ Favorable traits only, 19; one or more
unfavorable traits, 8; no answer, 4. The eight with
unfavorable moral traits are described as follows: 2 are "very
self-willed"; 1 "needs close watching"; 1 is "cruel to
animals"; 1 is "untruthful"; 1 is "unreliable"; 1 is "a
bluffer"; 1 is "sexually abnormal," "perverted," and
"vicious."
It will be noted that with the exception of the last child,
the moral irregularities mentioned can hardly be regarded,
from the psychological point of view, as essentially abnormal.
It is perhaps a good rather than a bad sign for a child to be
self-willed; most children "need close watching"; and a
certain amount of untruthfulness in children is the rule and
not the exception.
5. _Social adaptability._ Socially adaptable, 25; not adaptable,
2; doubtful, 4.
6. _Attitude of other children._ "Favorable," "friendly," "liked
by everybody," "much admired," "popular," etc., 26; "not
liked," 1; "inspires repugnance," 1; no answer, 1.
7. _Is child a leader?_ "Yes," 14; "no," or "not particularly,"
12; doubtful, 5.
8. _Is play life normal?_ "Yes," 26; "no," 1; "hardly," 1;
doubtful, 3.
9. _Is child spoiled or vain?_ "No," 22; "yes," 5; "somewhat," 2;
no answer, 2.
According to the above data, exceptionally intelligent children are
fully as likely to be healthy as ordinary children; their ability is far
more often general than special, they are studious above the average,
really serious faults are not common among them, they are nearly always
socially adaptable, are sought after as playmates and companions, their
play life is usually normal, they are leaders far oftener than other
children, and notwithstanding their many really superior qualities they
are seldom vain or spoiled.
It would be greatly to the advantage of such children if their superior
ability were more promptly and fully recognized, and if (under proper
medical supervision, of course) they were promoted as rapidly as their
mental development would warrant. Unless they are given the grade of
work which calls forth their best efforts, they run the risk of falling
into lifelong habits of submaximum efficiency. The danger in the case of
such children is not over-pressure, but under-pressure.
INTELLIGENCE TESTS AS A BASIS FOR GRADING. Not only in the case of
retarded or exceptionally bright children, but with many others also,
intelligence tests can aid in correctly placing the child in school.
The pupil who enters one school system from another is a case in point.
Such a pupil nearly always suffers a loss of time. The indefensible
custom is to grade the newcomer down a little, because, forsooth, the
textbooks he has studied may have differed somewhat from those he is
about to take up, or because the school system from which he comes may
be looked upon as inferior. Teachers are too often suspicious of all
other educational methods besides their own. The present treatment
accorded such children, which so often does them injustice and injury,
should be replaced by an intelligence test. The hour of time required
for the test is a small matter in comparison with the loss of a school
term by the pupils.
Indeed, it would be desirable to make all promotions on the basis
chiefly of intellectual ability. Hitherto the school has had to rely on
tests of information because reliable tests of intelligence have not
until recently been available. As trained Binet examiners become more
plentiful, the information standard will have to give way to the
criterion which asks merely that the child shall be able to do the work
of the next higher grade. The brief intelligence test is not only more
enlightening than the examination; it is also more hygienic. The school
examination is often for the child a source of worry and anxiety; the
mental test is an interesting and pleasant experience.
INTELLIGENCE TESTS FOR VOCATIONAL FITNESS. The time is probably not far
distant when intelligence tests will become a recognized and widely used
instrument for determining vocational fitness. Of course, it is not
claimed that tests are available which will tell us unerringly exactly
what one of a thousand or more occupations a given individual is best
fitted to pursue. But when thousands of children who have been tested by
the Binet scale have been followed out into the industrial world, and
their success in various occupations noted, we shall know fairly
definitely the vocational significance of any given degree of mental
inferiority or superiority. Researches of this kind will ultimately
determine the minimum "intelligence quotient" necessary for success in
each leading occupation.
Industrial concerns doubtless suffer enormous losses from the employment
of persons whose mental ability is not equal to the tasks they are
expected to perform. The present methods of trying out new employees,
transferring them to simpler and simpler jobs as their inefficiency
becomes apparent, is wasteful and to a great extent unnecessary. A
cheaper and more satisfactory method would be to employ a psychologist
to examine applicants for positions and to weed out the unfit. Any
business employing as many as five hundred or a thousand workers, as,
for example, a large department store, could save in this way several
times the salary of a well-trained psychologist.
That the industrially inefficient are often of subnormal intelligence
has already been demonstrated in a number of psychological
investigations. Of 150 "hoboes" tested under the direction of the writer
by Mr. Knollin, at least 15 per cent belonged to the moron grade of
mental deficiency, and almost as many more were border-line cases. To be
sure, a large proportion were found perfectly normal, and a few even
decidedly superior in mental ability, but the ratio of mental deficiency
was ten or fifteen times as high as that holding for the general
population. Several had as low as 9- or 10-year intelligence, and one
had a mental level of 7 years. The industrial history of such subjects,
as given by themselves, was always about what the mental level would
lead us to expect--unskilled work, lack of interest in accomplishment,
frequent discharge from jobs, discouragement, and finally the "road."
The above findings have been fully paralleled by Mr. Glenn Johnson and
Professor Eleanor Rowland, of Reed College, who tested 108 unemployed
charity cases in Portland, Oregon. Both of these investigators made use
of the Stanford revision of the Binet scale, which is especially
serviceable in distinguishing the upper-grade defectives from normals.
It hardly needs to be emphasized that when charity organizations help
the feeble-minded to float along in the social and industrial world, and
to produce and rear children after their kind, a doubtful service is
rendered. A little psychological research would aid the united charities
of any city to direct their expenditures into more profitable channels
than would otherwise be possible.
OTHER USES OF INTELLIGENCE TESTS. Another important use of intelligence
tests is in the study of the factors which influence mental development.
It is desirable that we should be able to guard the child against
influences which affect mental development unfavorably; but as long as
these influences have not been sifted, weighed, and measured, we have
nothing but conjecture on which to base our efforts in this direction.
When we search the literature of child hygiene for reliable evidence as
to the injurious effects upon mental ability of malnutrition, decayed
teeth, obstructed breathing, reduced sleep, bad ventilation,
insufficient exercise, etc., we are met by endless assertion painfully
unsupported by demonstrated fact. We have, indeed, very little exact
knowledge regarding the mental effects of any of the factors just
mentioned. When standardized mental tests have come into more general
use, such influences will be easy to detect wherever they are really
present.
Again, the most important question of heredity is that regarding the
inheritance of intelligence; but this is a problem which cannot be
attacked at all without some accurate means of identifying the thing
which is the object of study. Without the use of scales for measuring
intelligence we can give no better answer as to the essential difference
between a genius and a fool than is to be found in legend and fiction.
Applying this to school children, it means that without such tests we
cannot know to what extent a child's mental performances are determined
by environment and to what extent by heredity. Is the place of the
so-called lower classes in the social and industrial scale the result of
their inferior native endowment, or is their apparent inferiority merely
a result of their inferior home and school training? Is genius more
common among children of the educated classes than among the children of
the ignorant and poor? Are the inferior races really inferior, or are
they merely unfortunate in their lack of opportunity to learn?
Only intelligence tests can answer these questions and grade the raw
material with which education works. Without them we can never
distinguish the results of our educational efforts with a given child
from the influence of the child's original endowment. Such tests would
have told us, for example, whether the much-discussed "wonder children,"
such as the Sidis and Wiener boys and the Stoner girl, owe their
precocious intellectual prowess to superior training (as their parents
believe) or to superior native ability. The supposed effects upon mental
development of new methods of mind training, which are exploited so
confidently from time to time (e.g., the Montessori method and the
various systems of sensory and motor training for the feeble-minded),
will have to be checked up by the same kind of scientific measurement.
In all these fields intelligence tests are certain to play an
ever-increasing rôle. With the exception of moral character there
is nothing as significant for a child's future as his grade of
intelligence. Even health itself is likely to have less influence in
determining success in life. Although strength and swiftness have always
had great survival value among the lower animals, these characteristics
have long since lost their supremacy in man's struggle for existence.
For us the rule of brawn has been broken, and intelligence has become
the decisive factor in success. Schools, railroads, factories, and the
largest commercial concerns may be successfully managed by persons who
are physically weak or even sickly. One who has intelligence constantly
measures opportunities against his own strength or weakness and adjusts
himself to conditions by following those leads which promise most toward
the realization of his individual possibilities.
All classes of intellects, the weakest as well as the strongest, will
profit by the application of their talents to tasks which are consonant
with their ability. When we have learned the lessons which intelligence
tests have to teach, we shall no longer blame mentally defective workmen
for their industrial inefficiency, punish weak-minded children because
of their inability to learn, or imprison and hang mentally defective
criminals because they lacked the intelligence to appreciate the
ordinary codes of social conduct.
CHAPTER II
SOURCES OF ERROR IN JUDGING INTELLIGENCE
ARE INTELLIGENCE TESTS SUPERFLUOUS? Binet tells us that he often
encountered the criticism that intelligence tests are superfluous, and
that in going to so much trouble to devise his measuring scale he was
forcing an open door. Those who made this criticism believed that the
observant teacher or parent is able to make an offhand estimate of a
child's intelligence which is accurate enough. "It is a stupid teacher,"
said one, "who needs a psychologist to tell her which pupils are not
intelligent." Every one who uses intelligence tests meets this attitude
from time to time.
This should not be surprising or discouraging. It is only natural that
those who are unfamiliar with the methods of psychology should
occasionally question their validity or worth, just as there are many
excellent people who do not "believe in" vaccination against typhoid and
small pox, operations for appendicitis, etc.
There is an additional reason why the applications of psychology have to
overcome a good deal of conservatism and skepticism; namely, the fact
that every one, whether psychologically trained or not, acquires in the
ordinary experiences of life a certain degree of expertness in the
observation and interpretation of mental traits. The possession of this
little fund of practical working knowledge makes most people slow to
admit any one's claim to greater expertness. When the astronomer tells
us the distance to Jupiter, we accept his statement, because we
recognize that our ordinary experience affords no basis for judgment
about such matters. But every one acquires more or less facility in
distinguishing the coarser differences among people in intelligence,
and this half-knowledge naturally generates a certain amount of
resistance to the more refined method of tests.
It should be evident, however, that we need more than the ability merely
to distinguish a genius from a simpleton, just as a physician needs
something more than the ability to distinguish an athlete from a man
dying of consumption. It is necessary to have a definite and accurate
diagnosis, one which will differentiate more finely the many degrees and
qualities of intelligence. Just as in the case of physical illness, we
need to know not merely that the patient is sick, but also why he is
sick, what organs are involved, what course the illness will run, and
what physical work the patient can safely undertake, so in the case of a
retarded child, we need to know the exact degree of intellectual
deficiency, what mental functions are chiefly concerned in the defect,
whether the deficiency is due to innate endowment, to physical illness,
or to faults of education, and what lines of mental activity the child
will be able to pursue with reasonable hope of success. In the diagnosis
of a case of malnutrition, the up-to-date physician does not depend upon
general symptoms, but instead makes a blood test to determine the exact
number of red corpuscles per cubic millimeter of blood and the exact
percentage of hæmoglobin. He has learned that external appearances are
often misleading. Similarly, every psychologist who is experienced in
the mental examination of school children knows that his own or the
teacher's estimate of a child's intelligence is subject to grave and
frequent error.
THE NECESSITY OF STANDARDS. In the first place, in order to judge an
individual's intelligence it is necessary to have in mind some standard
as to what constitutes normal intelligence. This the ordinary parent or
teacher does not have. In the case of school children, for example, each
pupil is judged with reference to the average intelligence of the
class. But the teacher has no means of knowing whether the average for
her class is above, equal to, or below that for children in general. Her
standard may be too high, too low, vague, mechanical, or fragmentary.
The same, of course, holds in the case of parents or any one else
attempting to estimate intelligence on the basis of common observation.
THE INTELLIGENCE OF RETARDED CHILDREN USUALLY OVERESTIMATED. One of the
most common errors made by the teacher is to overestimate the
intelligence of the over-age pupil. This is because she fails to take
account of age differences and estimates intelligence on the basis of
the child's school performance in the grade where he happens to be
located. She tends to overlook the fact that quality of school work is
no index of intelligence unless age is taken into account. The question
should be, not, "Is this child doing his school work well?" but rather,
"In what school grade should a child of this age be able to do
satisfactory work?" A high-grade imbecile may do average work in the
first grade, and a high-grade moron average work in the third or fourth
grade, provided only they are sufficiently over-age for the grade in
question.
Our experience in testing children for segregation in special classes
has time and again brought this fallacy of teachers to our attention. We
have often found one or more feeble-minded children in a class after
the teacher had confidently asserted that there was not a single
exceptionally dull child present. In every case where there has been
opportunity to follow the later school progress of such a child the
validity of the intelligence test has been fully confirmed.
The following are typical examples of the neglect of teachers to take
the age factor into account when estimating the intelligence of the
over-age child:--
_A. R. Girl, age 11; in low second grade._ She was able to do
the work of this grade, not well, but passably. The teacher's
judgment as to this child's intelligence was "dull but not
defective." What the teacher overlooked was the fact that she
had judged the child by a 7-year standard, and that, instead of
only being able to do the work of the second grade
indifferently, a child of this age should have been equal to the
work of the fifth grade. In reality, A. R. is definitely
feeble-minded. Although she is from a home of average culture,
is 11 years old, and has attended school five years, she has
barely the intelligence of the average child of six years.
_D. C. Boy, age 17; in fifth grade._ His teacher knew that he
was dull, but had not thought of him as belonging to the class
of feeble-minded. She had judged this boy by the 11-year
standard and had perhaps been further misled by his normal
appearance and exceptionally satisfactory behavior. The Binet
test quickly showed that he had a mental level of approximately
9 years. There is little probability that his comprehension will
ever surpass that of the average 10-year-old.
_R. A. Boy, age 17; mental age 11; sixth grade; school work
"nearly average"; teacher's estimate of intelligence "average."_
Test plainly shows this child to be a high-grade moron, or
border-liner at best. Had attended school regularly 11 years and
had made 6 grades. Teacher had compared child with his
12-year-old classmates.
_H. A. Boy, age 14; mental age 9-6; low fourth grade; school
work "inferior"; teacher's estimate of intelligence "average."_
The teacher blamed the inferior quality of school work to "bad
home environment." As a matter of fact, the boy's father is
feeble-minded and the normality of the mother is questionable.
An older brother is in a reform school. We are perfectly safe in
predicting that this boy will not complete the eighth grade even
if he attends school till he is 21 years of age.
_F. I. Boy, age 12-11; mental age 9-4; third grade; school work
"average"; teacher's estimate of intelligence "average"; social
environment "average"; health good and attendance regular._
Intelligence and school success are what we should expect of an
average 9-year-old.
_D. A. Boy, age 12; mental age 9-2; third grade; school work
"inferior"; teacher's estimate of intelligence "average."_
Teacher imputes inferior school work to "absence from school and
lack of interest in books"; we have yet to find a child with a
mental age 25 per cent below chronological age who _was_
particularly interested in books or enthusiastic about school.
_C. U. Girl, age 10; mental age 7-8; second grade; school work
"average"; teacher's estimate of intelligence "average."_
Teacher blames adenoids and bad teeth for retardation. No doubt
of child's mental deficiency.
_P. I. Girl, age 8-10; mental age 6-7; has been in first grade
2½ years; school work "average"; teacher's estimate of
intelligence "average."_ The mother and one brother of this girl
are both feeble-minded.
_H. O. Girl, age 7-10; mental age 5-2; first grade for 2 years;
school work "inferior"; teacher's estimate of intelligence
"average."_ The teacher nevertheless adds, "This child is not
normal, but her ability to respond to drill shows that she has
intelligence." It is of course true that even feeble-minded
children of 5-year intelligence are able to profit a little from
drill. Their weakness comes to light in their inability to
perform higher types of mental activity.
THE INTELLIGENCE OF SUPERIOR CHILDREN USUALLY UNDERESTIMATED. We have
already mentioned the frequent failure of teachers and parents to
recognize superior ability.[7] The fallacy here is again largely due to
the neglect of the age factor, but the resulting error is in the
opposite direction from that set forth above. The superior child is
likely to be a year or two younger than the average child of his grade,
and is accordingly judged by a standard which is too high. The following
are illustrations:--
[7] See p. 13 _ff._
_M. L. Girl, age 11-2; mental age "average adult" (16); sixth
grade; school work "superior"; teacher's estimate of
intelligence "average."_ Teacher credits superior school work to
"unusual home advantages." Father a college professor. The
teacher considers the child accelerated in school. In reality
she ought to be in the second year of high school instead of in
the sixth grade.
_H. A. Boy, age 11; mental age 14; sixth grade; school work
"average"; teacher's estimate of intelligence "average."_
According to the supplementary information the boy is
"wonderfully attentive," "studious," and possessed of
"all-round ability." The estimate of "average intelligence" was
probably the result of comparing him with classmates who
averaged about a year older.
_K. R. Girl, age 6-1; mental age 8-5; second grade; school work
"average"; teacher's estimate of intelligence "superior"; social
environment "average."_ Is it not evident that a child from
ordinary social environment, who does work of average quality in
the second grade when barely 6 years of age, should be judged
"very superior" rather than merely "superior" in intelligence?
The intelligence quotient of this girl is 140, which is not
reached by more than one child in two hundred.
_S. A. Boy, age 8-10; mental age 10-9; fourth grade; school work
"average"; teacher's estimate of intelligence "average."_
Teacher attributed school acceleration to "studiousness" and
"delight in school work." It would be more reasonable to infer
that these traits are indications of unusually superior
intelligence.
OTHER FALLACIES IN THE ESTIMATION OF INTELLIGENCE. Another source
of error in the teacher's judgment comes from the difficulty in
distinguishing genuine dullness from the mental condition which results
sometimes from unfavorable social environment or lack of training.
_V. P. Boy, age 7._ Had attended school one year and had
profited very little from the instruction. He had learned to
read very little, spoke chiefly in monosyllables, and seemed
"queer." The teacher suspected his intelligence and asked for a
mental examination. The Binet test showed that except for
vocabulary, which was unusually low, there was practically no
mental retardation. Inquiry disclosed the fact that the boy's
parents were uneducated deaf-mutes, and that the boy had
associated little with other children. Four years later this boy
was doing fairly well in school, though a year retarded because
of his unfavorable home environment.
_X. Y. Boy, age 10._ Son of a successful business man, he was
barely able to read in the second reader. The Binet test
revealed an intelligence level which was absolutely normal. The
boy was removed to a special class where he could receive
individual attention, and two years later was found doing good
work in a regular class of the fifth grade. His bad beginning
seemed to have been due to an unfavorable attitude toward school
work, due in turn to lack of discipline in the home, and to the
fact that because of the father's frequent change of business
headquarters the boy had never attended one school longer than
three months.
Another source of error in judging intelligence from common observation
is the tendency to overestimate the intelligence of the sprightly,
talkative, sanguine child, and to underestimate the intelligence of the
child who is less emotional, reacts slowly, and talks little. One
occasionally finds a feeble-minded adult, perhaps of only 9- or 10-year
intelligence, whose verbal fluency, mental liveliness, and
self-confidence would mislead the offhand judgment of even the
psychologist. One individual of this type, a border-line case at best,
was accustomed to harangue street audiences and had served as "major" in
"Kelly's Army," a horde of several hundred unemployed men who a few
years ago organized and started to march from San Francisco to
Washington.
BINET'S QUESTIONNAIRE ON TEACHERS' METHODS OF JUDGING INTELLIGENCE.[8]
Aroused by the skepticism so often shown toward his test method, Binet
decided to make a little study of the methods by which teachers are
accustomed to arrive at a judgment as to a child's intelligence.
Accordingly, through the coöperation of the director of elementary
education in Paris, he secured answers from a number of teachers to the
following questions:--
[8] See p. 169 _ff._ of reference 2, at end of this book
1. _By what means do you judge the intelligence of your pupils?_
2. _How often have you been deceived in your judgments?_
About 40 replies were received. Most of the answers to the first
question were vague, one-sided, "verbal," or bookish. Only a few showed
much psychological discrimination as to what intelligence is and
what its symptoms are. There was a very general tendency to judge
intelligence by success in one or more of the school studies. Some
thought that ability to master arithmetic was a sure criterion. Others
were influenced almost entirely by the pupil's ability to read. One
teacher said that the child who can "read so expressively as to make you
feel the punctuation" is certainly intelligent, an observation which is
rather good, as far as it goes. A few judged intelligence by the pupil's
knowledge of such subjects as history and geography, which, as Binet
points out, is to confound intelligence with the ability to memorize.
"Memory," says Binet, is a "great simulator of intelligence." It is a
wise teacher who is not deceived by it. Only a small minority mentioned
resourcefulness in play, capacity to adjust to practical situations, or
any other out-of-school criteria.
Some suggested asking the pupil such questions as the following:--
"Why do you love your parents?" "If it takes three persons seven
hours to do a piece of work, would it take seven persons any
longer?" "Which would you rather have, a fourth of a pie, or a
half of a half?" "Which is heavier, a pound of feathers or a
pound of lead?" "If you had twenty cents what would you do with
it?"
A great many based their judgment mainly on the general appearance of
the face and eyes. An "active" or "passive" expression of the eyes was
looked upon as especially significant. One teacher thought that a mere
"glance of the eye" was sufficient to display the grade of intelligence.
If the eyes are penetrating, reflective, or show curiosity, the child
must be intelligent; if they are heavy and expressionless, he must be
dull. The mobility of countenance came in for frequent mention, also the
shape of the head.
No one will deny that intelligence displays itself to a greater or
less extent in the features; but how, asks Binet, are we going to
_standardize_ a "glance of the eye" or an "expression of curiosity" so
that it will serve as an exact measure of intelligence?
The fact is, the more one sees of feeble-minded children, the less
reliance one comes to place upon facial expression as a sign of
intelligence. Some children who are only slightly backward have the
general appearance of low-grade imbeciles. On the other hand, not a few
who are distinctly feeble-minded are pretty and attractive. With many
such children a ready smile takes the place of comprehension. If the
smile is rather sweet and sympathetic, as is often the case, the
observer is almost sure to be deceived.
As regards the shape of the head, peculiar conformation of the ears, and
other "stigmata," science long ago demonstrated that these are
ordinarily of little or no significance.
In reply to the second question, some teachers stated that they never
made a mistake, while others admitted failure in one case out of three.
Still others said, "Once in ten years," "once in twenty years," "once in
a thousand times," etc.
As Binet remarks, the answers to this question are not very enlightening.
In the first place, the teacher as a rule loses sight of the pupil when
he has passed from her care, and seldom has opportunity of finding out
whether his later success belies her judgment or confirms it. Errors go
undiscovered for the simple reason that there is no opportunity to check
them up. In the second place, her estimate is so rough that an error
must be very great in order to have any meaning. If I say that a man is
six feet and two inches tall, it is easy enough to apply a measuring
stick and prove the correctness or incorrectness of my assertion. But if
I say simply that the man is "rather tall," or "very tall," the error
must be very extreme before we can expose it, particularly since the
estimate can itself be checked up only by observation and not by
controlled experiment.
The teachers' answers seem to justify three conclusions:--
1. Teachers do not have a very definite idea of what constitutes
intelligence. They tend to confuse it variously with capacity for
memorizing, facility in reading, ability to master arithmetic, etc. On
the whole, their standard is too academic. They fail to appreciate the
one-sidedness of the school's demands upon intelligence.
In a quaintly humorous passage discussing this tendency, Binet
characterizes the child in a class as _dénaturé_, a French word which we
may translate (though rather too literally) as "denatured." Too often
this "denatured" child of the classroom is the only child the teacher
knows.
2. In judging intelligence teachers are too easily deceived by a
sprightly attitude, a sympathetic expression, a glance of the eye, or a
chance "bump" on the head.
3. Although a few teachers seem to realize the many possibilities of
error, the majority show rather undue confidence in the accuracy of
their judgment.
BINET'S EXPERIMENT ON HOW TEACHERS TEST INTELLIGENCE.[9] Finally, Binet
had three teachers come to his laboratory to judge the intelligence of
children whom they had never seen before. Each spent an afternoon in the
laboratory and examined five pupils. In each case the teacher was left
free to arrive at a conclusion in her own way. Binet, who remained in
the room and took notes, recounts with playful humor how the teachers
were unavoidably compelled to resort to the much-abused test method,
although their attempts at using it were sometimes, from the
psychologist's point of view, amusingly clumsy.
[9] See p. 182 _ff._ of reference 2 at end of this book.
One teacher, for example, questioned the children about some canals and
sluices which were in the vicinity, asking what their purpose was and
how they worked. Another showed the children some pretty pictures,
which she had brought with her for the purpose, and asked questions
about them. Showing the picture of a garret, she asked how a garret
differs from an ordinary room. One teacher asked whether in building a
factory it was best to have the walls thick or thin. As King Edward had
just died, another teacher questioned the children about the details of
this event, in order to find out whether they were in the habit of
reading the newspapers, or understood the things they heard others read.
Other questions related to the names of the streets in the neighborhood,
the road one should take to reach a certain point in the vicinity, etc.
Binet notes that many of the questions were special, and were only
applicable with the children of this particular school.
The method of proposing the questions and judging the responses was also
at fault. The teachers did not adhere consistently to any definite
formula in giving a particular test to the different children. Instead,
the questions were materially altered from time to time. One teacher
scored the identical response differently for two children, giving one
child more credit than the other because she had already judged his
intelligence to be superior. In several cases the examination was
needlessly delayed in order to instruct the child in what he did not
know.
The examination ended, quite properly for a teacher's examination, with
questions about history, literature, the metric system, etc., and with
the recitation of a fable.
A comparison of the results showed hardly any agreement among the
estimates of the three teachers. When questioned about the standard that
had been taken in arriving at their conclusions, one teacher said she
had taken the answers of the first pupil as a point of departure, and
that she had judged the other pupils by this one. Another judged all the
children by a child of her acquaintance whom she knew to be intelligent.
This was, of course, an unsafe method, because no one could say how the
child taken as an ideal would have responded to the tests used with the
five children.
In summarizing the result of his little experiment, Binet points out
that the teachers employed, as if by instinct, the very method which he
himself recommends. In using it, however, they made numerous errors.
Their questions were often needlessly long. Several were "dilemma
questions," that is, answerable by _yes_ or _no_. In such cases chance
alone will cause fifty per cent of the answers to be correct. Some of
the questions were merely tests of school knowledge. Others were
entirely special, usable only with the children of this particular
school on this particular day. Not all of the questions were put in the
same terms, and a given response did not always receive the same score.
When the children responded incorrectly or incompletely, they were often
given help, but not always to the same extent. In other words, says
Binet, it was evident that "the teachers employed very awkwardly a very
excellent method."
The above remark is as pertinent as it is expressive. As the statement
implies, the test method is but a refinement and standardization of the
common-sense approach. Binet remarks that most people who inquire into
his method of measuring intelligence do so expecting to find something
very surprising and mysterious; and on seeing how much it resembles the
methods which common sense employs in ordinary life, they heave a sigh
of disappointment and say, "Is that all?" Binet reminds us that the
difference between the scientific and unscientific way of doing a thing
is not necessarily a difference in the _nature_ of the method; it is
often merely a difference in _exactness_. Science does the thing better,
because it does it more accurately.
It was of course not the purpose of Binet to cast a slur upon the good
sense and judgment of teachers. The teachers who took part in the little
experiment described above were Binet's personal friends. The errors he
points out in his entertaining and good-humored account of the
experiment are inherent in the situation. They are the kind of errors
which any person, however discriminating and observant, is likely to
make in estimating the intelligence of a subject without the use of
standardized tests.
It is the writer's experience that the teacher's estimate of a child's
intelligence is much more reliable than that of the average parent; more
accurate even than that of the physician who has not had psychological
training.
Indeed, it is an exceptional school physician who is able to give any
very valuable assistance to teachers in the classification of mentally
exceptional children for special pedagogical treatment.
This is only to be expected, for the physician has ordinarily had much
less instruction in psychology than the teacher, and of course
infinitely less experience in judging the mental performances of
children. Even if graduated from a first-rank medical school, the
instruction he has received in the important subject of mental
deficiency has probably been less adequate than that given to the
students of a standard normal school. As a rule, the doctor has no
equipment or special fitness which gives him any advantage over the
teacher in acquiring facility in the use of intelligence tests.
As for parents, it would of course be unreasonable to expect from them a
very accurate judgment regarding the mental peculiarities of their
children. The difficulty is not simply that which comes from lack of
special training. The presence of parental affection renders impartial
judgment impossible. Still more serious are the effects of habituation
to the child's mental traits. As a result of such habituation the most
intelligent parent tends to develop an unfortunate blindness to all
sorts of abnormalities which exist in his own children.
The only way of escape from the fallacies we have mentioned lies in the
use of some kind of refined psychological procedure. Binet testing is
destined to become universally known and practiced in schools, prisons,
reformatories, charity stations, orphan asylums, and even ordinary
homes, for the same reason that Babcock testing has become universal in
dairying. Each is indispensable to its purpose.
CHAPTER III
DESCRIPTION OF THE BINET-SIMON METHOD
ESSENTIAL NATURE OF THE SCALE. The Binet scale is made up of an extended
series of tests in the nature of "stunts," or problems, success in which
demands the exercise of intelligence. As left by Binet, the scale
consists of 54 tests, so graded in difficulty that the easiest lie well
within the range of normal 3-year-old children, while the hardest tax
the intelligence of the average adult. The problems are designed
primarily to test native intelligence, not school knowledge or home
training. They try to answer the question "How intelligent is this
child?" How much the child has learned is of significance only in so far
as it throws light on his ability to learn more.
Binet fully appreciated the fact that intelligence is not homogeneous,
that it has many aspects, and that no one kind of test will display it
adequately. He therefore assembled for his intelligence scale tests of
many different types, some of them designed to display differences of
memory, others differences in power to reason, ability to compare, power
of comprehension, time orientation, facility in the use of number
concepts, power to combine ideas into a meaningful whole, the maturity
of apperception, wealth of ideas, knowledge of common objects, etc.
HOW THE SCALE WAS DERIVED. The tests were arranged in order of
difficulty, as found by trying them upon some 200 normal children of
different ages from 3 to 15 years. It was found, for illustration, that
a certain test was passed by only a very small proportion of the younger
children, say the 5-year-olds, and that the number passing this test
increased rapidly in the succeeding years until by the age of 7 or
8 years, let us say, practically all the children were successful.
If, in our supposed case, the test was passed by about two thirds to
three fourths of the normal children aged 7 years, it was considered by
Binet a test of 7-year intelligence. In like manner, a test passed by
65 to 75 per cent of the normal 9-year-olds was considered a test of
9-year intelligence, and so on. By trying out many different tests in
this way it was possible to secure five tests to represent each age from
3 to 10 years (excepting age 4, which has only four tests), five for
age 12, five for 15, and five for adults, making 54 tests in all.
LIST OF TESTS. The following is the list of tests as arranged by Binet
in 1911, shortly before his untimely death:--
_Age 3:_
1. Points to nose, eyes, and mouth.
2. Repeats two digits.
3. Enumerates objects in a picture.
4. Gives family name.
5. Repeats a sentence of six syllables.
_Age 4:_
1. Gives his sex.
2. Names key, knife, and penny.
3. Repeats three digits.
4. Compares two lines.
_Age 5:_
1. Compares two weights.
2. Copies a square.
3. Repeats a sentence of ten syllables.
4. Counts four pennies.
5. Unites the halves of a divided rectangle.
_Age 6:_
1. Distinguishes between morning and afternoon.
2. Defines familiar words in terms of use.
3. Copies a diamond.
4. Counts thirteen pennies.
5. Distinguishes pictures of ugly and pretty faces.
_Age 7:_
1. Shows right hand and left ear.
2. Describes a picture.
3. Executes three commissions, given simultaneously.
4. Counts the value of six sous, three of which are double.
5. Names four cardinal colors.
_Age 8:_
1. Compares two objects from memory.
2. Counts from 20 to 0.
3. Notes omissions from pictures.
4. Gives day and date.
5. Repeats five digits.
_Age 9:_
1. Gives change from twenty sous.
2. Defines familiar words in terms superior to use.
3. Recognizes all the pieces of money.
4. Names the months of the year, in order.
5. Answers easy "comprehension questions."
_Age 10:_
1. Arranges five blocks in order of weight.
2. Copies drawings from memory.
3. Criticizes absurd statements.
4. Answers difficult "comprehension questions."
5. Uses three given words in not more than two sentences.
_Age 12:_
1. Resists suggestion.
2. Composes one sentence containing three given words.
3. Names sixty words in three minutes.
4. Defines certain abstract words.
5. Discovers the sense of a disarranged sentence.
_Age 15:_
1. Repeats seven digits.
2. Finds three rhymes for a given word.
3. Repeats a sentence of twenty-six syllables.
4. Interprets pictures.
5. Interprets given facts.
_Adult:_
1. Solves the paper-cutting test.
2. Rearranges a triangle in imagination.
3. Gives differences between pairs of abstract terms.
4. Gives three differences between a president and a king.
5. Gives the main thought of a selection which he has heard read.
It should be emphasized that merely to name the tests in this way gives
little idea of their nature and meaning, and tells nothing about Binet's
method of conducting the 54 experiments. In order to use the tests
intelligently it is necessary to acquaint one's self thoroughly with the
purpose of each test, its correct procedure, and the psychological
interpretation of different types of response.[10]
[10] See Part II of this volume, and References 1 and 29, for discussion
and interpretation of the individual tests.
In fairness to Binet, it should also be borne in mind that the scale of
tests was only a rough approximation to the ideal which the author had
set himself to realize. Had his life been spared a few years longer, he
would doubtless have carried the method much nearer perfection.
HOW THE SCALE IS USED. By means of the Binet tests we can judge the
intelligence of a given individual by comparison with standards of
intellectual performance for normal children of different ages. In order
to make the comparison it is only necessary to begin the examination of
the subject at a point in the scale where all the tests are passed
successfully, and to continue up the scale until no more successes are
possible. Then we compare our subject's performances with the standard
for normal children of the same age, and note the amount of acceleration
or retardation.
Let us suppose the subject being tested is 9 years of age. If he goes as
far in the tests as normal 9-year-old children ordinarily go, we can say
that the child has a "mental age" of 9 years, which in this case is
normal (our child being 9 years of age). If he goes only as far as
normal 8-year-old children ordinarily go, we say that his "mental age"
is 8 years. In like manner, a mentally defective child of 9 years may
have a "mental age" of only 4 years, or a young genius of 9 years may
have a mental age of 12 or 13 years.
SPECIAL CHARACTERISTICS OF THE BINET-SIMON METHOD. Psychologists had
experimented with intelligence tests for at least twenty years before
the Binet scale made its appearance. The question naturally suggests
itself why Binet should have been successful in a field where previous
efforts had been for the most part futile. The answer to this question
is found in three essential differences between Binet's method and those
formerly employed.
1. _The use of age standards._ Binet was the first to utilize the idea
of age standards, or norms, in the measurement of intelligence. It will
be understood, of course, that Binet did not set out to invent tests of
10-year intelligence, 6-year intelligence, etc. Instead, as already
explained, he began with a series of tests ranging from very easy to
very difficult, and by trying these tests on children of different ages
and noting the percentages of successes in the various years, he was
able to locate them (approximately) in the years where they belonged.
This plan has the great advantage of giving us standards which are
easily grasped. To say, for illustration, that a given subject has a
grade of intelligence equal to that of the average child of 8 years is a
statement whose general import does not need to be explained. Previous
investigators had worked with subjects the degree of whose intelligence
was unknown, and with tests the difficulty of which was equally unknown.
An immense amount of ingenuity was spent in devising tests which were
used in such a way as to preclude any very meaningful interpretation of
the responses.
The Binet method enables us to characterize the intelligence of a child
in a far more definite way than had hitherto been possible. Current
descriptive terms like "bright," "moderately bright," "dull," "very
dull," "feeble-minded," etc., have had no universally accepted meaning.
A child who is designated by one person as "moderately bright" may be
called "very bright" by another person. The degree of intelligence which
one calls "moderate dullness," another may call "extreme dullness," etc.
But every one knows what is meant by the term 8-year mentality, 4-year
mentality, etc., even if he is not able to define these grades of
intelligence in psychological terms; and by ascertaining experimentally
what intellectual tasks children of different ages can perform, we are,
of course, able to make our age standards as definite as we please.
Why should a device so simple have waited so long for a discoverer? We
do not know. It is of a class with many other unaccountable mysteries in
the development of scientific method. Apparently the idea of an
age-grade method, as this is called, did not come to Binet himself until
he had experimented with intelligence tests for some fifteen years. At
least his first provisional scale, published in 1905, was not made up
according to the age-grade plan. It consisted merely of 30 tests,
arranged roughly in order of difficulty. Although Binet nowhere gives
any account of the steps by which this crude and ungraded scale was
transformed into the relatively complete age-grade scale of 1908, we can
infer that the original and ingenious idea of utilizing age norms was
suggested by the data collected with the 1905 scale. However the
discovery was made, it ranks, perhaps, from the practical point of view,
as the most important in all the history of psychology.
2. _The kind of mental functions brought into play._ In the second
place, the Binet tests differ from most of the earlier attempts in that
they are designed to test the higher and more complex mental processes,
instead of the simpler and more elementary ones. Hence they set
problems for the reasoning powers and ingenuity, provoke judgments about
abstract matters, etc., instead of attempting to measure sensory
discrimination, mere retentiveness, rapidity of reaction, and the like.
Psychologists had generally considered the higher processes too complex
to be measured directly, and accordingly sought to get at them
indirectly by correlating supposed intelligence with simpler processes
which could readily be measured, such as reaction time, rapidity of
tapping, discrimination of tones and colors, etc. While they were
disputing over their contradictory findings in this line of exploration,
Binet went directly to the point and succeeded where they had failed.
It is now generally admitted by psychologists that higher intelligence
is little concerned in such elementary processes as those mentioned
above. Many of the animals have keen sensory discrimination.
Feeble-minded children, unless of very low grade, do not differ very
markedly from normal children in sensitivity of the skin, visual
acuity, simple reaction time, type of imagery, etc. But in power of
comprehension, abstraction, and ability to direct thought, in the nature
of the associative processes, in amount of information possessed, and in
spontaneity of attention, they differ enormously.
3. _Binet would test "general intelligence."_ Finally, Binet's success
was largely due to his abandonment of the older "faculty psychology"
which, far from being defunct, had really given direction to most of the
earlier work with mental tests. Where others had attempted to measure
memory attention, sense discrimination, etc., as separate faculties or
functions, Binet undertook to ascertain the _general level_ of
intelligence. Others had thought the task easier of accomplishment by
measuring each division or aspect of intelligence separately, and
summating the results. Binet, too, began in this way, and it was only
after years of experimentation by the usual methods that he finally
broke away from them and undertook, so to speak, to triangulate the
height of his tower without first getting the dimensions of the
individual stones which made it up.
The assumption that it is easier to measure a part, or one aspect, of
intelligence than all of it, is fallacious in that the parts are not
separate parts and cannot be separated by any refinement of experiment.
They are interwoven and intertwined. Each ramifies everywhere and
appears in all other functions. The analogy of the stones of the tower
does not really apply. Memory, for example, cannot be tested separately
from attention, or sense-discrimination separately from the associative
processes. After many vain attempts to disentangle the various
intellective functions, Binet decided to test their combined functional
capacity without any pretense of measuring the exact contribution
of each to the total product. It is hardly too much to say that
intelligence tests have been successful just to the extent to which they
have been guided by this aim.
Memory, attention, imagination, etc., are terms of "structural
psychology." Binet's psychology is dynamic. He conceives intelligence as
the sum total of those thought processes which consist in mental
adaptation. This adaptation is not explicable in terms of the old mental
"faculties." No one of these can explain a single thought process, for
such process always involves the participation of many functions whose
separate rôles are impossible to distinguish accurately. Instead of
measuring the intensity of various mental states (psycho-physics), it is
more enlightening to measure their combined effect on adaptation. Using
a biological comparison, Binet says the old "faculties" correspond to
the separate tissues of an animal or plant, while his own "scheme of
thought" corresponds to the functioning organ itself. For Binet,
psychology is the science of behavior.
BINET'S CONCEPTION OF GENERAL INTELLIGENCE. In devising tests of
intelligence it is, of course, necessary to be guided by some
assumption, or assumptions, regarding the nature of intelligence. To
adopt any other course is to depend for success upon happy chance.
However, it is impossible to arrive at a final definition of
intelligence on the basis of _a-priori_ considerations alone. To demand,
as critics of the Binet method have sometimes done, that one who would
measure intelligence should first present a complete definition of it,
is quite unreasonable. As Stern points out, electrical currents were
measured long before their nature was well understood. Similar
illustrations could be drawn from the processes involved in chemistry
physiology, and other sciences. In the case of intelligence it may be
truthfully said that no adequate definition can possibly be framed which
is not based primarily on the symptoms empirically brought to light by
the test method. The best that can be done in advance of such data is to
make tentative assumptions as to the probable nature of intelligence,
and then to subject these assumptions to tests which will show their
correctness or incorrectness. New hypotheses can then be framed for
further trial, and thus gradually we shall be led to a conception of
intelligence which will be meaningful and in harmony with all the
ascertainable facts.
Such was the method of Binet. Only those unacquainted with Binet's
more than fifteen years of labor preceding the publication of his
intelligence scale would think of accusing him of making no effort to
analyze the mental processes which his tests bring into play. It is true
that many of Binet's earlier assumptions proved untenable, and in this
event he was always ready, with exceptional candor and intellectual
plasticity, to acknowledge his error and to plan a new line of attack.
Binet's conception of intelligence emphasizes three characteristics of
the thought process: (1) Its tendency to take and maintain a definite
direction; (2) the capacity to make adaptations for the purpose of
attaining a desired end; and (3) the power of auto-criticism.[11]
[11] See Binet and Simon: "L'intelligence des imbeciles," in _L'Année
Psychologique_ (1909), pp. 1-147. The last division of this article is
devoted to a discussion of the essential nature of the higher thought
processes, and is a wonderful example of that keen psychological
analysis in which Binet was so gifted.
How these three aspects of intelligence enter into the performances with
various tests of the scale is set forth from time to time in our
directions for giving and interpreting the individual tests.[12] An
illustration which may be given here is that of the "patience test," or
uniting the disarranged parts of a divided rectangle. As described by
Binet, this operation has the following elements: "(1) to keep in mind
the end to be attained, that is to say, the figure to be formed; (2) to
try different combinations under the influence of this directing idea,
which guides the efforts of the subject even though he may not be
conscious of the fact; and (3) to judge the combination which has been
made, to compare it with the model, and to decide whether it is the
correct one."
[12] See especially pages 162 and 238.
Much the same processes are called for in many other of the Binet tests,
particularly those of arranging weights, rearranging dissected
sentences, drawing a diamond or square from copy, finding a sentence
containing three given words, counting backwards, etc.
However, an examination of the scale will show that the choice of tests
was not guided entirely by any single formula as to the nature of
intelligence. Binet's approach was a many-sided one. The scale includes
tests of time orientation, of three or four kinds of memory, of
apperception, of language comprehension, of knowledge about common
objects, of free association, of number mastery, of constructive
imagination, and of ability to compare concepts, to see contradictions,
to combine fragments into a unitary whole, to comprehend abstract terms,
and to meet novel situations.
OTHER CONCEPTIONS OF INTELLIGENCE. It is interesting to compare Binet's
conception of intelligence with the definitions which have been offered
by other psychologists. According to Ebbinghaus, for example, the
essence of intelligence lies in comprehending together in a unitary,
meaningful whole, impressions and associations which are more or less
independent, heterogeneous, or even partly contradictory. "Intellectual
ability consists in the elaboration of a whole into its worth and
meaning by means of many-sided combination, correction, and completion
of numerous kindred associations.... It is a _combination activity_."
Meumann offers a twofold definition. From the psychological point of
view, intelligence is the power of independent and creative elaboration
of new products out of the material given by memory and the senses. From
the practical point of view, it involves the ability to avoid errors, to
surmount difficulties, and to adjust to environment.
Stern defines intelligence as "the general capacity of an individual
consciously to adjust his thinking to new requirements: it is general
adaptability to new problems and conditions of life."
Spearman, Hart, and others of the English school define intelligence as
a "common central factor" which participates in all sorts of
special mental activities. This factor is explained in terms of a
psycho-physiological hypothesis of "cortex energy," "cerebral
plasticity," etc.
The above definitions are only to a slight extent contradictory or
inharmonious. They differ mainly in point of view or in the location of
the emphasis. Each expresses a part of the truth, and none all of it. It
will be evident that the conception of Binet is broad enough to include
the most important elements in each of the other definitions quoted.
GUIDING PRINCIPLES IN CHOICE AND ARRANGEMENT OF TESTS. In choosing his
tests Binet was guided by the conception of intelligence which we have
set forth above. Tests were devised which would presumably bring
into play the various mental processes thought to be concerned in
intelligence, and then these tests were tried out on normal children of
different ages. If the percentage of passes for a given test increased
but little or not at all in going from younger to older children this
test was discarded. On the other hand, if the proportion of passes
increased rapidly with age, and if children of a given age, who on other
grounds were known to be bright, passed more frequently than children of
the same age who were known to be dull, then the test was judged a
satisfactory test of intelligence. As we have shown elsewhere,[13]
practically all of Binet's tests fulfill these requirements reasonably
well, a fact which bears eloquent testimony to the keen psychological
insight of their author.
[13] See p. 55.
In arranging the tests into a system Binet's guiding principle was to
find an arrangement of the tests which would cause an average child of
any given age to test "at age"; that is, the average 5-year-old must
show a mental age of 5 years, the average 8-year-old a mental age of
8 years, etc. In order to secure this result Binet found that his data
seemed to require the location of an individual test in that year where
it was passed by about two thirds to three fourths of unselected
children.
It was in the assembling of the tests that the most serious faults of
the scale had their origin. Further investigation has shown that a great
many of the tests were misplaced as much as one year, and several of
them two years. On the whole, the scale as Binet left it was decidedly
too easy in the lower ranges, and too difficult in the upper. As a
result, the average child of 5 years was caused to test at not far from
6 years, the average child of 12 years not far from 11. In the Stanford
revision an effort has been made to correct this fault, along with
certain other generally recognized imperfections.
SOME AVOWED LIMITATIONS OF THE BINET TESTS. The Binet tests have often
been criticized for their unfitness to perform certain services which in
reality they were never meant to render. This is unfair. We cannot make
a just evaluation of the scale without bearing in mind its avowed
limitations.
For example, the scale does not pretend to measure the entire mentality
of the subject, but only _general intelligence_. There is no pretense of
testing the emotions or the will beyond the extent to which these
naturally display themselves in the tests of intelligence. The scale was
not designed as a tool for the analysis of those emotional or volitional
aberrations which are concerned in such mental disorders as hysteria,
insanity, etc. These conditions do not present a progressive reduction
of intelligence to the infantile level, and in most of them other
factors besides intelligence play an important rôle. Moreover, even in
the normal individual the fruitfulness of intelligence, the direction in
which it shall be applied, and its methods of work are to a certain
extent determined by the extraneous factors of emotion and volition.
It should, nevertheless, be pointed out that defects of intelligence, in
a large majority of cases, also involve disturbances of the emotional
and volitional functions. We do not expect to find perfectly normal
emotions or will power of average strength coupled with marked
intellectual deficiency, and as a matter of fact such a combination is
rare indeed. In the course of an examination with the Binet tests, the
experienced clinical psychologist is able to gain considerable insight
into the subject's emotional and volitional equipment, even though the
method was designed primarily for another purpose.
A second misunderstanding can be avoided by remembering that the Binet
scale does not pretend to bring to light the idiosyncrasies of special
talent, but only to measure the general level of intelligence. It cannot
be used for the discovery of exceptional ability in drawing, painting,
music, mathematics, oratory, salesmanship, etc., because no effort is
made to explore the processes underlying these abilities. It can,
therefore, never serve as a _detailed chart_ for the vocational guidance
of children, telling us which will succeed in business, which in art,
which in medicine, etc. It is not a new kind of phrenology. At the same
time, as we have already pointed out, _it is capable of bounding roughly
the vocational territory in which an individual's intelligence will
probably permit success, nothing else preventing_.[14]
[14] See p. 17.
In the third place, it must not be supposed that the scale can be used
as a complete pedagogical guide. Although intelligence tests furnish
data of the greatest significance for pedagogical procedure, they do not
suggest the appropriate educational methods in detail. These will
have to be worked out in a practical way for the various grades of
intelligence, and at great cost of labor and patience.
Finally, in arriving at an estimate of a subject's grade of intelligence
and his susceptibility to training, it would be a mistake to ignore the
data obtainable from other sources. No competent psychologist, however
ardent a supporter of the Binet method he might be, would recommend such
a policy. Those who accept the method as all-sufficient are as much in
error as those who consider it as no more important than any one of a
dozen other approaches. Standardized tests have already become and will
remain by far the most reliable single method for grading intelligence,
but the results they furnish will always need to be interpreted in the
light of supplementary information regarding the subject's personal
history, including medical record, accidents, play habits, industrial
efficiency, social and moral traits, school success, home environment,
etc. Without question, however, the improved Binet tests will contribute
more than all other data combined to the end of enabling us to forecast
a child's possibilities of future improvement, and this is the
information which will aid most in the proper direction of his
education.
CHAPTER IV
NATURE OF THE STANFORD REVISION AND EXTENSION
Although the Binet scale quickly demonstrated its value as an instrument
for the classification of mentally-retarded and otherwise exceptional
children, it had, nevertheless, several imperfections which greatly
limited its usefulness. There was a dearth of tests at the higher mental
levels, the procedure was so inadequately defined that needless
disagreement came about in the interpretation of data, and so many of
the tests were misplaced as to make the results of an examination more
or less misleading, particularly in the case of very young subjects and
those near the adult level. It was for the purpose of correcting
these and certain other faults that the Stanford investigation was
planned.[15]
[15] The writer wishes to acknowledge his very great indebtedness to
Miss Grace Lyman, Dr. George Ordahl, Dr. Louise Ellison Ordahl, Miss
Neva Galbreath, Mr. Wilford Talbert, Dr. J. Harold Williams, Mr. Herbert
E. Knollin, and Miss Irene Cuneo for their coöperation in making the
tests on which the Stanford revision is chiefly based. Without their
loyal assistance the investigation could not have been carried through.
Grateful acknowledgment is also made to the many public school teachers
and principals for their generous and invaluable coöperation in
furnishing subjects for the tests, and in supplying, sometimes at
considerable cost of labor, the supplementary information which was
called for regarding the pupils tested. Their contribution was made in
the interest of educational science, and without expectation of personal
benefits of any kind. Their professional spirit cannot be too highly
commended.
SOURCES OF DATA. Our revision is the result of several years of work,
and involved the examination of approximately 2300 subjects, including
1700 normal children, 200 defective and superior children, and more than
400 adults.
Tests of 400 of the 1700 normal children had been made by Childs and
Terman in 1910-11, and of 300 children by Trost, Waddle, and Terman in
1911-12. For various reasons, however, the results of these tests did
not furnish satisfactory data for a thoroughgoing revision of the scale.
Accordingly a new investigation was undertaken, somewhat more extensive
than the others, and more carefully planned. Its main features may be
described as follows:--
1. The first step was to assemble as nearly as possible all the results
which had been secured for each test of the scale by all the workers of
all countries. The result was a large sheet of tabulated data for each
individual test, including percentages passing the test at various ages,
conditions under which the results were secured, method of procedure,
etc. After a comparative study of these data, and in the light of
results we had ourselves secured, a provisional arrangement of the tests
was prepared for try-out.
2. In addition to the tests of the original Binet scale, 40 additional
tests were included for try-out. This, it was expected, would make
possible the elimination of some of the least satisfactory tests, and at
the same time permit the addition of enough new ones to give at least
six tests, instead of five, for each age group.
3. A plan was then devised for securing subjects who should be as nearly
as possible representative of the several ages. The method was to select
a school in a community of average social status, a school attended by
all or practically all the children in the district where it was
located. In order to get clear pictures of age differences the tests
were confined to children who were within two months of a birthday. To
avoid accidental selection, _all_ the children within two months of a
birthday were tested, in whatever grade enrolled. Tests of foreign-born
children, however, were eliminated in the treatment of results. There
remained tests of approximately 1000 children, of whom 905 were between
5 and 14 years of age.
4. The children's responses were, for the most part, recorded
_verbatim_. This made it possible to re-score the records according
to any desired standard, and thus to fit a test more perfectly to the
age level assigned it.
5. Much attention was given to securing uniformity of procedure. A
half-year was devoted to training the examiners and another half-year to
the supervision of the testing. In the further interests of uniformity
all the records were scored by one person (the writer).
METHOD OF ARRIVING AT A REVISION. The revision of the scale below
the 14-year level was based almost entirely on the tests of the
above-mentioned 1,000 unselected children. The guiding principle was to
secure an arrangement of the tests and a standard of scoring which would
cause the median mental age of the unselected children of each age group
to coincide with the median chronological age. That is, a correct scale
must cause the _average_ child of 5 years to test exactly at 5, the
_average_ child at 6 to test exactly at 6, etc. Or, to express the same
fact in terms of intelligence quotient,[16] a correct scale must give a
median intelligence quotient of unity, or 100 per cent, for unselected
children of each age.
[16] The intelligence quotient (often designated as I Q) is the ratio of
mental age to chronological age. (See pp. 65 _ff._ and 78 _ff._)
If the median mental age resulting at any point from the provisional
arrangement of tests was too high or too low, it was only necessary to
change the location of certain of the tests, or to change the standard
of scoring, until an order of arrangement and a standard of passing were
found which would throw the median mental age where it belonged. We had
already become convinced, for reasons too involved for presentation
here, that no satisfactory revision of the Binet scale was possible on
any theoretical considerations as to the percentage of passes which an
individual test ought to show in a given year in order to be considered
standard for that year.
As was to be expected, the first draft of the revision did not prove
satisfactory. The scale was still too hard at some points, and too easy
at others. In fact, three successive revisions were necessary, involving
three separate scorings of the data and as many tabulations of the
mental ages, before the desired degree of accuracy was secured. As
finally revised, the scale gives a median intelligence quotient closely
approximating 100 for the unselected children of each age from 4 to 14.
Since our school children who were above 14 years and still in the
grades were retarded left-overs, it was necessary to base the revision
above this level on the tests of adults. These included 30 business men
and 150 "migrating" unemployed men tested by Mr. H. E. Knollin, 150
adolescent delinquents tested by Mr. J. Harold Williams, and 50
high-school students tested by the writer.
The extension of the scale in the upper range is such that ordinarily
intelligent adults, little educated, test up to what is called the
"average adult" level. Adults whose intelligence is known from other
sources to be superior are found to test well up toward the "superior
adult" level, and this holds whether the subjects in question are well
educated or practically unschooled. The almost entirely unschooled
business men, in fact, tested fully as well as high-school juniors and
seniors.
Figure 1 shows the distribution of mental ages for 62 adults, including
the 30 business men and the 32 high-school pupils who were over 16 years
of age. It will be noted that the middle section of the graph represents
the "mental ages" falling between 15 and 17. This is the range which we
have designated as the "average adult" level. Those above 17 are called
"superior adults," those between 13 and 15, "inferior adults." Subjects
much over 15 years of age who test in the neighborhood of 12 years may
ordinarily be considered border-line cases.
[Illustration: FIG. 1. DISTRIBUTION OF MENTAL AGES OF 62 NORMAL ADULTS]
The following method was employed for determining the validity of a
test. The children of each age level were divided into three groups
according to intelligence quotient, those testing below 90, those
between 90 and 109, and those with an intelligence quotient of 110 or
above. The percentages of passes on each individual test at or near that
age level were then ascertained separately for these three groups. If a
test fails to show a decidedly higher proportion of passes in the
superior I Q group than in the inferior I Q group, it cannot be regarded
as a satisfactory test of intelligence. On the other hand, a test which
satisfies this criterion must be accepted as valid or the entire scale
must be rejected. Henceforth it stands or falls with the scale as a
whole.
When tried out by this method, some of the tests which have been most
criticized showed a high degree of reliability; certain others which
have been considered excellent proved to be so little correlated with
intelligence that they had to be discarded.
After making a few necessary eliminations, 90 tests remained, or 36 more
than the number included in the Binet 1911 scale. There are 6 at each
age level from 3 to 10, 8 at 12, 6 at 14, 6 at "average adult," 6 at
"superior adult," and 16 alternative tests. The alternative tests, which
are distributed among the different groups, are intended to be used only
as substitutes when one or more of the regular tests have been rendered,
by coaching or otherwise, undesirable.[17]
[17] See p. 137 _ff._ for explanations regarding the calculation of
mental age and the use of alternative tests.
Of the 36 new tests, 27 were added and standardized in the various
Stanford investigations. Two tests were borrowed from the Healy-Fernald
series, one from Kuhlmann, one was adapted from Bonser, and the
remaining five were amplifications or adaptations of some of the earlier
Binet tests.
Following is a complete list of the tests of the Stanford revision.
Those designated _al._ are alternative tests. The guide for giving and
scoring the tests is presented at length in Part II of this volume.
_The Stanford revision and extension_
_Year III._ (_6 tests, 2 months each._)
1. Points to parts of body. (3 to 4.)
Nose; eyes; mouth; hair.
2. Names familiar objects. (3 to 5.)
Key, penny, closed knife, watch, pencil.
3. Pictures, enumeration or better. (At least 3 objects enumerated
in one picture.)
(a) Dutch Home; (b) River Scene; (c) Post-Office.
4. Gives sex.
5. Gives last name.
6. Repeats 6 to 7 syllables. (1 to 3.)
Al. Repeats 3 digits. (1 success in 3 trials. Order correct.)
_Year IV._ (_6 tests, 2 months each._)
1. Compares lines. (3 trials, no error.)
2. Discrimination of forms. (Kuhlmann.) (Not over 3 errors.)
3. Counts 4 pennies. (No error.)
4. Copies square. (Pencil. 1 to 3.)
5. Comprehension, 1st degree. (2 to 3.) (Stanford addition.)
"What must you do": "When you are sleepy?" "Cold?" "Hungry?"
6. Repeats 4 digits. (1 to 3. Order correct.) (Stanford addition.)
Al. Repeats 12 to 13 syllables. (1 to 3 absolutely correct, or 2 with
1 error each.)
_Year V._ (_6 tests, 2 months each._)
1. Comparison of weights. (2 to 3.)
3-15; 15-3; 3-15.
2. Colors. (No error.)
Red; yellow; blue; green.
3. Æsthetic comparison. (No error.)
4. Definitions, use or better. (4 to 6.)
Chair; horse; fork; doll; pencil; table.
5. Patience, or divided rectangle. (2 to 3 trials. 1 minute each.)
6. Three commissions. (No error. Order correct.)
Al. Age.
_Year VI._ (_6 tests, 2 months each._)
1. Right and left. (No error.)
Right hand; left ear; right eye.
2. Mutilated pictures. (3 to 4 correct.)
3. Counts 13 pennies. (1 to 2 trials, without error.)
4. Comprehension, 2d degree. (2 to 3.) "What's the thing for
you to do":
(a) "If it is raining when you start to school?"
(b) "If you find that your house is on fire?"
(c) "If you are going some place and miss your car?"
5. Coins. (3 to 4.)
Nickel; penny; quarter; dime.
6. Repeats 16 to 18 syllables. (1 to 3 absolutely correct, or 2
with 1 error each.)
Al. Morning or afternoon.
_Year VII._ (_6 tests, 2 months each._)
1. Fingers. (No error.) Right; left; both.
2. Pictures, description or better. (Over half of performance
description:) Dutch Home; River Scene; Post-Office.
3. Repeats 5 digits. (1 to 3. Order correct.)
4. Ties bow-knot. (Model shown. 1 minute.) (Stanford addition.)
5. Gives differences. (2 to 3.)
Fly and butterfly; stone and egg; wood and glass.
6. Copies diamond. (Pen. 2 to 3.)
Al. 1. Names days of week. (Order correct. 2 to 3 checks correct.)
Al. 2. Repeats 3 digits backwards. (1 to 3.)
_Year VIII._ (_6 tests, 2 months each._)
1. Ball and field. (Inferior plan or better.) (Stanford addition.)
2. Counts 20 to 1. (40 seconds. 1 error allowed.)
3. Comprehension, 3d degree. (2 to 3.) "What's the thing for you to
do":
(a) "When you have broken something which belongs to some one
else?"
(b) "When you are on your way to school and notice that you are
in danger of being tardy?"
(c) "If a playmate hits you without meaning to do it?"
4. Gives similarities, two things. (2 to 4.) (Stanford addition.)
Wood and coal; apple and peach; iron and silver; ship and
automobile.
5. Definitions superior to use. (2 to 4.)
Balloon; tiger; football; soldier.
6. Vocabulary, 20 words. (Stanford addition. For list of words used,
see record booklet.)
Al. 1. First six coins. (No error.)
Al. 2. Dictation. ("See the little boy." Easily legible. Pen. 1 minute.)
_Year IX._ (_6 tests, 2 months each._)
1. Date. (Allow error of 3 days in _c_, no error in _a_, _b_, or _d_.)
(a) day of week; (b) month; (c) day of month; (d) year.
2. Weights. (3, 6, 9, 12, 15. Procedure not illustrated. 2 to 3.)
3. Makes change. (2 to 3. No coins, paper, or pencil.)
10--4; 15--12; 25--4.
4. Repeats 4 digits backwards. (1 to 3.) (Stanford addition.)
5. Three words. (2 to 3. Oral. 1 sentence or not over 2 coördinate
clauses.)
Boy, river, ball; work, money, men; desert, rivers, lakes.
6. Rhymes. (3 rhymes for two of three words. 1 minute for each part.)
Day; mill; spring.
Al. 1. Months. (15 seconds and 1 error in naming. 2 checks of 3 correct.)
Al. 2. Stamps, gives total value. (Second trial if individual values are
known.)
_Year X._ (_6 tests, 2 months each._)
1. Vocabulary, 30 words. (Stanford addition.)
2. Absurdities. (4 to 5. Warn. Spontaneous correction allowed.) (Four
of Binet's, one Stanford.)
3. Designs. (1 correct, 1 half correct. Expose 10 seconds.)
4. Reading and report. (8 memories. 35 seconds and 2 mistakes in
reading.) (Binet's selection.)
5. Comprehension, 4th degree. (2 to 3. Question may be repeated.)
(a) "What ought you to say when some one asks your opinion
about a person you don't know very well?"
(b) "What ought you to do before undertaking (beginning)
something very important?"
(c) "Why should we judge a person more by his actions than by
his words?"
6. Names 60 words. (Illustrate with clouds, dog, chair, happy.)
Al. 1. Repeats 6 digits. (1 to 2. Order correct.) (Stanford addition.)
Al. 2. Repeats 20 to 22 syllables. (1 to 3 correct, or 2 with 1 error
each.)
Al. 3. Form board. (Healy-Fernald Puzzle A. 3 times in 5 minutes.)
_Year XII._ (_8 tests, 3 months each._)
1. Vocabulary, 40 words. (Stanford addition.)
2. Abstract words. (3 to 5.)
Pity; revenge; charity; envy; justice.
3. Ball and field. (Superior plan.) (Stanford addition.)
4. Dissected sentences. (2 to 3. 1 minute each.)
5. Fables. (Score 4; i.e., two correct or the equivalent in half
credits.) (Stanford addition.)
Hercules and Wagoner; Maid and Eggs; Fox and Crow;
Farmer and Stork; Miller, Son, and Donkey.
6. Repeats 5 digits backwards. (1 to 3.) (Stanford addition.)
7. Pictures, interpretation. (3 to 4. "Explain this picture.")
Dutch Home; River Scene; Post-Office; Colonial Home.
8. Gives similarities, three things. (3 to 5.) (Stanford addition.)
Snake, cow, sparrow; book, teacher, newspaper; wool, cotton,
leather; knife-blade, penny, piece of wire; rose, potato,
tree.
_Year XIV._ (_6 tests, 4 months each._)
1. Vocabulary, 50 words. (Stanford addition.)
2. Induction test. (Gets rule by 6th folding.) (Stanford addition.)
3. President and king. (Power; accession; tenure. 2 to 3.)
4. Problems of fact. (2 to 3.) (Binet's two and one Stanford
addition.)
5. Arithmetical reasoning. (1 minute each. 2 to 3.) (Adapted from
Bonser.)
6. Clock. (2 to 3. Error must not exceed 3 or 4 minutes.)
6.22. 8.10. 2.46.
Al. Repeats 7 digits. (1 to 2. Order correct.)
"AVERAGE ADULT." (_6 tests, 5 months each._)
1. Vocabulary, 65 words. (Stanford addition.)
2. Interpretation of fables. (Score 8.) (Stanford addition.)
3. Difference between abstract words. (3 real contrasts out of 4.)
Laziness and idleness; evolution and revolution; poverty and
misery; character and reputation.
4. Problem of the enclosed boxes. (3 to 4.) (Stanford addition.)
5. Repeats 6 digits backwards. (1 to 3.) (Stanford addition.)
6. Code, writes "Come quickly." (2 errors. Omission of dot counts
half error. Illustrate with "war" and "spy.") (From Healy and
Fernald.)
Al. 1. Repeats 28 syllables. (1 to 2 absolutely correct.)
Al. 2. Comprehension of physical relations. (2 to 3.) (Stanford addition.)
Path of cannon ball; weight of fish in water; hitting distant
mark.
"SUPERIOR ADULT." (_6 tests, 6 months each._)
1. Vocabulary, 75 words. (Stanford addition.)
2. Binet's paper-cutting test. (Draws, folds, and locates holes.)
3. Repeats 8 digits. (1 to 3. Order correct.) (Stanford addition.)
4. Repeats thought of passage heard. (1 to 2.) (Binet's and Wissler's
selections adapted.)
5. Repeats 7 digits backwards. (1 to 3.) (Stanford addition.)
6. Ingenuity test. (2 to 3. 5 minutes each.) (Stanford addition.)
SUMMARY OF CHANGES. A comparison of the above list with either the Binet
1908 or 1911 series will reveal many changes. On the whole, it differs
somewhat more from the Binet 1911 scale than from that of 1908. Thus, of
the 49 tests below the "adult" group in the 1911 scale, 2 are eliminated
and 29 are relocated. Of these, 25 are moved downward and 4 upward. The
shifts are as follows:--
Down 1 year, 18
Down 2 years, 4
Down 3 years, 2
Down 6 years, 1
Up 1 year, 3
Up 2 years, 1
Of the adult group in Binet's 1911 series 1 is eliminated, 2 are moved
up to "superior adult," and 1 is moved up to 14. Accordingly, of Binet's
entire 54 tests, we have eliminated 3 and relocated 32, leaving only 19
in the positions assigned them by Binet. The 3 eliminated are: repeating
2 digits, resisting suggestion, and "reversed triangle."
The revision is really more extensive than the above figures would
suggest, since minor changes have been made in the scoring of a great
many tests in order to make them fit better the locations assigned them.
Throughout the scale the procedure and scoring have been worked over and
made more definite with the idea of promoting uniformity. This phase of
the revision is perhaps more important than the mere relocation of
tests. Also, the addition of numerous tests in the upper ranges of the
scale affects very considerably the mental ages above the level of
10 or 11 years.
EFFECTS OF THE REVISION ON THE MENTAL AGES SECURED. The most important
effect of the revision is to reduce the mental ages secured in the lower
ranges of the scale, and to raise considerably the mental ages above
10 or 11 years. This difference also obtains, though to a somewhat
smaller extent, between the Stanford revision and those of Goddard and
Kuhlmann.
For example, of 104 adult individuals testing by the Stanford revision
between 12 and 14 years, and who were therefore somewhat above the level
of feeble-mindedness as that term is usually defined, 50 per cent tested
below 12 years by the Goddard revision. That the dull and border-line
adults are so much more readily distinguished from the feeble-minded by
the Stanford revision than by other Binet series is due as much to the
addition of tests in the upper groups as to the relocation of existing
tests.
On the other hand, the Stanford revision causes young subjects to test
lower than any other version of the Binet scale. At 5 or 6 years the
mental ages secured by the Stanford revision average from 6 to 10 months
lower than other revisions yield.
The above differences are more significant than would at first appear.
An error of 10 months in the mental age of a 5-year-old is as serious as
an error of 20 months in the case of a 10-year-old. Stating the error in
terms of the intelligence quotient makes it more evident. Thus, an error
of 10 months in the mental age of a 5-year-old means an error of almost
15 per cent in the intelligence quotient. A scale which tests this much
too low would cause the child with a true intelligence quotient of 75
(which ordinarily means feeble-mindedness or border-line intelligence)
to test at 90, or only slightly below normal.
Three serious consequences came from the too great ease of the original
Binet scale at the lower end, and its too great difficulty at the upper
end:--
1. In young subjects the higher grades of mental deficiency were
overlooked, because the scale caused such subjects to test only a little
below normal.
2. The proportion of feeble-mindedness among adult subjects was greatly
overestimated, because subjects who were really of the 12- or 13-year
mental level could only earn a mental age of about 11 years.
3. Confusion resulted in efforts to trace the mental growth of either
feeble-minded or normal children. For example, by other versions of the
Binet scale an average 5-year-old will show an intelligence quotient
probably not far from 110 or 115; at 9, an intelligence quotient of
about 100; and at 14, an intelligence quotient of about 85 or 90.
By such a scale the true border-line case would test approximately as
follows:--
At age 5, 90 I Q (apparently not far below normal).
At age 9, 75 I Q (border-line).
At age 14, 65 I Q (moron deficiency).
On the other hand, re-tests of children by the Stanford revision have
been found to yield intelligence quotients almost identical with those
secured from two to four years earlier by the same tests. Those who
graded feeble-minded in the first test graded feeble-minded in the
second test: the dull remained dull, the average remained average, the
superior remained superior, and always in approximately the same
degree.[18]
[18] See "Some Problems relating to the Detection of Border-line Cases
of Mental Deficiency," by Lewis M. Terman and H. E. Knollin, in _Journal
of Psycho-Asthemes_, June, 1916.
It is unnecessary to emphasize further the importance of having an
intelligence scale which is equally accurate at all points. Absolute
perfection in this respect is not claimed for the Stanford revision, but
it is believed to be at least free from the more serious errors of other
Binet arrangements.
CHAPTER V
ANALYSIS OF 1000 INTELLIGENCE QUOTIENTS
An extended account of the 1000 tests on which the Stanford revision is
chiefly based has been presented in a separate monograph. This chapter
will include only the briefest summary of some of those results of the
investigation which contribute to the intelligent use of the revision.
THE DISTRIBUTION OF INTELLIGENCE. The question as to the manner in which
intelligence is distributed is one of great practical as well as
theoretical importance. One of the most vital questions which can be
asked by any nation of any age is the following: "How high is the
average level of intelligence among our people, and how frequent are the
various grades of ability above and below the average?" With the
development of standardized tests we are approaching, for the first time
in history, a possible answer to this question.
Most of the earlier Binet studies, however, have thrown little light on
the distribution of intelligence because of their failure to avoid the
influence of accidental selection in choosing subjects for testing. The
method of securing subjects for the Stanford revision makes our results
on this point especially interesting.[19] It is believed that the
subjects used for this investigation were as nearly representative of
average American-born children as it is possible to secure.
[19] See p. 52 _ff._ for method used to avoid accidental selection of
subjects for the Stanford investigation.
The intelligence quotients for these 1000 unselected children were
calculated, and their distribution was plotted for the ages separately.
The distribution was found fairly symmetrical at each age from 5 to 14.
At 15 the range is on either side of 90 as a median, and at 16 on either
side of 80 as a median. That the 15- and 16-year-olds test low is due to
the fact that these children are left-over retardates and are below
average in intelligence.
[Illustration: FIG. 2. DISTRIBUTION OF I Q'S OF 905 UNSELECTED
CHILDREN. 5-14 YEARS OF AGE]
The I Q's were then grouped in ranges of ten. In the middle group were
thrown those from 96 to 105; the ascending groups including in order the
I Q's from 106 to 115, 116 to 125, etc.; correspondingly with the
descending groups. Figure 2 shows the distribution found by this
grouping for the 905 children of ages 5 to 14 combined. The subjects
above 14 are not included in this curve because they are left-overs and
not representative of their ages.
The distribution for the ages combined is seen to be remarkably
symmetrical. The symmetry for the separate ages was hardly less marked,
considering that only 80 to 120 children were tested at each age. In
fact, the range, including the middle 50 per cent of I Q's, was found
practically constant from 5 to 14 years. The tendency is for the middle
50 per cent to fall (approximately) between 93 and 108.
Three important conclusions are justified by the above facts:--
1. Since the frequency of the various grades of intelligence decreases
_gradually_ and at no point abruptly on each side of the median, it is
evident that there is no definite dividing line between normality and
feeble-mindedness, or between normality and genius. Psychologically, the
mentally defective child does not belong to a distinct type, nor does
the genius. There is no line of demarcation between either of these
extremes and the so-called "normal" child. The number of mentally
defective individuals in a population will depend upon the standard
arbitrarily set up as to what constitutes mental deficiency. Similarly
for genius. It is exactly as we should undertake to classify all people
into the three groups: abnormally tall, normally tall, and abnormally
short.[20]
[20] See Chapter VI for discussion of the significance of various I Q's.
2. The common opinion that extreme deviations below the median are more
frequent than extreme deviations above the median seems to have no
foundation in fact. Among unselected school children, at least, for
every child of any given degree of deficiency there is another child as
far above the average I Q as the former is below. We have shown
elsewhere the serious consequences of neglect of this fact.[21]
[21] See p. 12 _ff._
3. The traditional view that variability in mental traits becomes more
marked during adolescence is here contradicted, as far as intelligence
is concerned, for the distribution of I Q's is practically the same at
each age from 5 to 14. For example, 6-year-olds differ from one another
fully as much as do 14-year-olds.
THE VALIDITY OF THE INTELLIGENCE QUOTIENT. The facts presented above
argue strongly for the validity of the I Q as an expression of a child's
intelligence status. This follows necessarily from the similar nature of
the distributions at the various ages. The inference is that a child's
I Q, as measured by this scale, remains relatively constant. Re-tests of
the same children at intervals of two to five years support the
inference. Children of superior intelligence do not seem to deteriorate
as they get older, nor dull children to develop average intelligence.
Knowing a child's I Q, we can predict with a fair degree of accuracy the
course of his later development.
The mental age of a subject is meaningless if considered apart from
chronological age. It is only the ratio of retardation or acceleration
to chronological age (that is, the I Q) which has significance.
It follows also that if the I Q is a valid expression of intelligence,
as it seems to be, then the Binet-Simon "age-grade method" becomes
transformed automatically into a "point-scale method," if one wants to
use it that way. As such it is superior to any other point scale that
has been proposed, because it includes a larger number of tests and its
points have definite meaning.[22]
[22] For discussion of the supposed advantages of the "point-scale
method," see Yerkes and Bridges: _A New Point Scale for Measuring Mental
Ability_. (Warwick and York, 1915.)
SEX DIFFERENCES. The question as to the relative intelligence of the
sexes is one of perennial interest and great social importance. The
ancient hypothesis, the one which dates from the time when only men
concerned themselves with scientific hypotheses, took for granted the
superiority of the male. With the development of individual psychology,
however, it was soon found that as far as the evidence of mental tests
can be trusted the _average_ intelligence of women and girls is as high
as that of men and boys.
If we accept this result we are then confronted with the difficult
problem of finding an explanation for the fact that so few of those who
have acquired eminence in the various intellectual fields have been
women. Two explanations have been proposed: (1) That women become
eminent less often than men simply for lack of opportunity and stimulus;
and (2) that while the average intelligence of the sexes is the same,
extreme variations may be more common in males. It is pointed out that
not only are there more eminent men than eminent women, but that
statistics also show a preponderance of males in institutions for the
mentally defective. Accordingly it is often said that women are grouped
closely about the average, while men show a wider range of distribution.
[Illustration: FIG. 3. MEDIAN I Q OF 457 BOYS (UNBROKEN LINE) AND
448 GIRLS (DOTTED LINE) FOR THE AGES 5-14 YEARS]
Many hundreds of articles and books of popular or quasi-scientific
nature have been written on one aspect or another of this question of
sex difference in intelligence; but all such theoretical discussions
taken together are worth less than the results of one good experiment.
Let us see what our 1000 I Q's have to offer toward a solution of the
problem.
1. When the I Q's of the boys and girls were treated separately there
was found a small but fairly constant superiority of the girls up to the
age of 13 years. At 14, however, the curve for the girls dropped below
that for boys. This is shown in Figure 3.
The supplementary data, including the teachers' estimates of
intelligence on a scale of five, the teachers' judgments in regard to
the quality of the school work, and records showing the age-grade
distribution of the sexes, were all sifted for evidence as to the
genuineness of the apparent superiority of the girls age for age. The
results of all these lines of inquiry support the tests in suggesting
that the superiority of the girls is probably real even up to and
including age 14, the apparent superiority of the boys at this age being
fully accounted for by the more frequent elimination of 14-year-old
girls from the grades by promotion to the high school.[23]
[23] It will be remembered that this series of tests did not follow up
and test those who had been promoted to high school.
2. However, the superiority of girls over boys is so slight (amounting
at most ages to only 2 to 3 points in terms of I Q) that for practical
purposes it would seem negligible. This offers no support to the opinion
expressed by Yerkes and Bridges that "at certain ages serious injustice
will be done individuals by evaluating their scores in the light of
norms which do not take account of sex differences."
3. Apart from the small superiority of girls, the distribution of
intelligence in the two sexes is not different. The supposed wider
variation of boys is not found. Girls do not group themselves about the
median more closely than do boys. The range of I Q including the middle
fifty per cent is approximately the same for the two sexes.[24]
[24] For an extensive summary of other data on the variability of the
sexes see the article by Leta S. Hollingworth, in _The American Journal
of Sociology_ (January, 1914), pp. 510-30. It is shown that the findings
of others support the conclusions set forth above.
4. When the results for the individual tests were examined, it was found
that not many showed very extreme differences as to the per cent of boys
and girls passing. In a few cases, however, the difference was rather
marked.
The boys were decidedly better in arithmetical reasoning, giving
differences between a president and a king, solving the form board,
making change, reversing hands of clock, finding similarities, and
solving the "induction test." The girls were superior in drawing designs
from memory, æsthetic comparison, comparing objects from memory,
answering the "comprehension questions," repeating digits and sentences,
tying a bow-knot, and finding rhymes.
Accordingly, our data, which for the most part agree with the results of
others, justify the conclusion that the intelligence of girls, at least
up to 14 years, does not differ materially from that of boys either as
regards the average level or the range of distribution. It may still be
argued that the mental development of boys beyond the age of 14 years
lasts longer and extends farther than in the case of girls, but as a
matter of fact this opinion receives little support from such tests as
have been made on men and women college students.
The fact that so few women have attained eminence may be due to wholly
extraneous factors, the most important of which are the following: (1)
The occupations in which it is possible to achieve eminence are for the
most part only now beginning to open their doors to women. Women's
career has been largely that of home-making, an occupation in which
eminence, in the strict sense of the word, is impossible. (2) Even of
the small number of women who embark upon a professional career, a
majority marry and thereafter devote a fairly large proportion of their
energy to bearing and rearing children. (3) Both the training given to
girls and the general atmosphere in which they grow up are unfavorable
to the inculcation of the professional point of view, and as a result
women are not spurred on by deep-seated motives to constant and
strenuous intellectual endeavor as men are. (4) It is also possible that
the emotional traits of women are such as to favor the development of
the sentiments at the expense of innate intellectual endowment.
INTELLIGENCE OF THE DIFFERENT SOCIAL CLASSES. Of the 1000 children, 492
were classified by their teachers according to social class into the
following five groups: _very inferior_, _inferior_, _average_,
_superior_, and _very superior_. A comparative study was then made of
the distribution of I Q's for these different groups.[25]
[25] The results of this comparison have been set forth in detail in the
monograph of source material and some of the conclusions have been set
forth on p. 115 _ff._ of the present volume.
The data may be summarized as follows:--
1. The median I Q for children of the superior social class is
about 7 points above, and that of the inferior social class
about 7 points below, the median I Q of the average social
group. This means that by the age of 14 inferior class children
are about one year below, and superior class children one year
above, the median mental age for all classes taken together.
2. That the children of the superior social classes make a
better showing in the tests is probably due, for the most part,
to a superiority in original endowment. This conclusion is
supported by five supplementary lines of evidence: (a) the
teachers' rankings of the children according to intelligence;
(b) the age-grade progress of the children; (c) the quality
of the school work; (d) the comparison of older and younger
children as regards the influence of social environment; and
(e) the study of individual cases of bright and dull children
in the same family.
3. In order to facilitate comparison, it is advisable to express
the intelligence of children of all social classes in terms of
the same objective scale of intelligence. This scale should be
based on the median for all classes taken together.
4. As regards their responses to individual tests, our children
of a given social class were not distinguishable from children
of the same intelligence in any other social class.
THE RELATION OF THE I Q TO THE QUALITY OF THE CHILD'S SCHOOL WORK. The
school work of 504 children was graded by the teachers on a scale of
five grades: _very inferior_, _inferior_, _average_, _superior_, and
_very superior_. When this grouping was compared with that made on the
basis of I Q, fairly close agreement was found. However, in about one
case out of ten there was rather serious disagreement; a child, for
example, would be rated as doing _average_ school work when his I Q
would place him in the _very inferior_ intelligence group.
When the data were searched for explanations of such disagreements it
was found that most of them were plainly due to the failure of teachers
to take into account the age of the child when grading the quality of
his school work.[26] When allowance was made for this tendency there
were no disagreements which justified any serious suspicion as to the
accuracy of the intelligence scale. Minor disagreements may, of course,
be disregarded, since the quality of school work depends in part on
other factors than intelligence, such as industry, health, regularity of
attendance, quality of instruction, etc.
[26] See p. 24 _ff._
THE RELATION BETWEEN I Q AND GRADE PROGRESS. This comparison, which was
made for the entire 1000 children, showed a fairly high correlation, but
also some astonishing disagreements. Nine-year intelligence was found
all the way from grade 1 to grade 7, inclusive; 10-year intelligence all
the way from grade 2 to grade 7; and 12-year intelligence all the way
from grade 3 to grade 8. Plainly the school's efforts at grading fail to
give homogeneous groups of children as regards mental ability. On the
whole, the grade location of the children did not fit their mental ages
much better than it did their chronological ages.
When the data were examined, it was found that practically every child
whose grade failed to correspond fairly closely with his mental age was
either exceptionally bright or exceptionally dull. Those who tested
between 96 and 105 I Q were never seriously misplaced in school. The
very dull children, however, were usually located from one to three
grades above where they belonged by mental age, and the duller the
child the more serious, as a rule, was the misplacement. On the other
hand, the very bright children were nearly always located from one to
three grades below where they belonged by mental age, and the brighter
the child the more serious the school's mistake. The child of 10-year
mental age in the second grade, for example, is almost certain to be
about 7 or 8 years old; the child of 10-year intelligence in the sixth
grade is almost certain to be 13 to 15 years of age.
All this is due to one fact, and one alone: _the school tends to promote
children by age rather than ability_. The bright children are held back,
while the dull children are promoted beyond their mental ability. The
retardation problem is exactly the reverse of what we have thought it to
be. It is the bright children who are retarded, and the dull children
who are accelerated.
The remedy is to be sought in differentiated courses (special classes)
for both kinds of mentally exceptional children. Just as many special
classes are needed for superior children as for the inferior. The social
consequences of suitable educational advantages for children of superior
ability would no doubt greatly exceed anything that could possibly
result from the special instruction of dullards and border-line
cases.[27]
[27] See Chapter VI for further discussion of the school progress
possible to children of various I Q's.
Special study of the I Q's between 70 and 79 revealed the fact that a
child of this grade of intelligence _never_ does satisfactory work in
the grade where he belongs by chronological age. By the time he has
attended school four or five years, such a child is usually found doing
"very inferior" to "average" work in a grade from two to four years
below his age.
On the other hand, the child with an I Q of 120 or above is almost never
found below the grade for his chronological age, and occasionally he is
one or two grades above. Wherever located, his work is always "superior"
or "very superior," and the evidence suggests strongly that it would
probably remain so even if extra promotions were granted.
CORRELATION BETWEEN I Q AND THE TEACHERS' ESTIMATES OF THE CHILDREN'S
INTELLIGENCE. By the Pearson formula the correlation found between the
I Q's and the teachers' rankings on a scale of five was .48. This is
about what others have found, and is both high enough and low enough to
be significant. That it is moderately high in so far corroborates the
tests. That it is not higher means that either the teachers or the tests
have made a good many mistakes.
When the data were searched for evidence on this point, it was found, as
we have shown in Chapter II, that the fault was plainly on the part of
the teachers. The serious mistakes were nearly all made with children
who were either over age or under age for their grade, mostly the
former. In estimating children's intelligence, just as in grading their
school success, the teachers often failed to take account of the age
factor. For example, the child whose mental age was, say, two years
below normal, and who was enrolled in a class with children about two
years younger than himself, was often graded "average" in intelligence.
The tendency of teachers is to estimate a child's intelligence according
to the quality of his school work _in the grade where he happens to be
located_. This results in overestimating the intelligence of older,
retarded children, and underestimating the intelligence of the younger,
advanced children. The disagreements between the tests and the teachers'
estimates are thus found, when analyzed, to confirm the validity of the
test method rather than to bring it under suspicion.
THE VALIDITY OF THE INDIVIDUAL TESTS. The validity of each test was
checked up by measuring it against the scale as a whole in the manner
described on p. 55. For example, if 10-year-old children having 11-year
intelligence succeed with a given test decidedly better than 10-year-old
children who have 9-year intelligence, then either this test must be
accepted as valid or the scale as a whole must be rejected. Since we
know, however, that the scale as a whole has at least a reasonably high
degree of reliability, this method becomes a sure and ready means of
judging the worth of a test.
When the tests were tried out in this way it was found that some of
those which have been most criticized have in reality a high correlation
with intelligence. Among these are naming the days of the week, giving
the value of stamps, counting thirteen pennies, giving differences
between president and king, finding rhymes, giving age, distinguishing
right and left, and interpretation of pictures. Others having a high
reliability are the vocabulary tests, arithmetical reasoning, giving
differences, copying a diamond, giving date, repeating digits in reverse
order, interpretation of fables, the dissected sentence test, naming
sixty words, finding omissions in pictures, and recognizing absurdities.
Among the somewhat less satisfactory tests are the following: repeating
digits (direct order), naming coins, distinguishing forenoon and
afternoon, defining in terms of use, drawing designs from memory, and
æsthetic comparison. Binet's "line suggestion" test correlated so little
with intelligence that it had to be thrown out. The same was also true
of two of the new tests which we had added to the series for try-out.
Tests showing a medium correlation with the scale as a whole include
arranging weights, executing three commissions, naming colors, giving
number of fingers, describing pictures, naming the months, making
change, giving superior definitions, finding similarities, reading for
memories, reversing hands of clock, defining abstract words, problems of
fact, bow-knot, induction test, and comprehension questions.
A test which makes a good showing on this criterion of agreement with
the scale as a whole becomes immune to theoretical criticisms. Whatever
it appears to be from mere inspection, it is a real measure of
intelligence. Henceforth it stands or falls with the scale as a whole.
The reader will understand, of course, that no single test used alone
will determine accurately the general level of intelligence. A great
many tests are required; and for two reasons: (1) because intelligence
has many aspects; and (2) in order to overcome the accidental influences
of training or environment. If many tests are used no one of them need
show more than a moderately high correlation with the scale as a whole.
As stated by Binet, "Let the tests be rough, if there are only enough of
them."
CHAPTER VI
THE SIGNIFICANCE OF VARIOUS INTELLIGENCE QUOTIENTS
FREQUENCY OF DIFFERENT DEGREES OF INTELLIGENCE. Before we can interpret
the results of an examination it is necessary to know how frequently an
I Q of the size found occurs among unselected children. Our tests of
1000 unselected children enable us to answer this question with some
degree of definiteness. A study of these 1000 I Q's shows the following
significant facts:--
The lowest 1 % go to 70 or below, the highest 1 % reach 130 or above
" " 2 % " " 73 " " " " 2 % " 128 " "
" " 3 % " " 76 " " " " 3 % " 125 " "
" " 5 % " " 78 " " " " 5 % " 122 " "
" " 10 % " " 85 " " " " 10 % " 116 " "
" " 15 % " " 88 " " " " 15 % " 113 " "
" " 20 % " " 91 " " " " 20 % " 110 " "
" " 25 % " " 92 " " " " 25 % " 108 " "
" " 33+1/3% " " 95 " " " " 33+1/3% " 106 " "
Or, to put some of the above facts in another form:--
The child reaching 110 is equaled or excelled by 20 out of 100
" " " (about) 115 " " " " " 10 " " "
" " " " 125 " " " " " 3 " " "
" " " " 130 " " " " " 1 " " "
Conversely, we may say regarding the subnormals that:--
The child testing at (about) 90 is equaled or excelled by 80 out of 100
" " " " " 85 " " " " " 90 " " "
" " " " " 75 " " " " " 97 " " "
" " " " " 70 " " " " " 99 " " "
CLASSIFICATION OF INTELLIGENCE QUOTIENTS. What do the above I Q's imply
in such terms as feeble-mindedness, border-line intelligence, dullness,
normality, superior intelligence genius, etc.? When we use these terms
two facts must be borne in mind: (1) That the boundary lines between
such groups are absolutely arbitrary, a matter of definition only; and
(2) that the individuals comprising one of the groups do not make up a
homogeneous type.
Nevertheless, since terms like the above are convenient and will
probably continue to be used, it is desirable to give them as much
definiteness as possible. On the basis of the tests we have made,
including many cases of all grades of intelligence, the following
suggestions are offered for the classification of intelligence
quotients:--
_I Q_ _Classification_
Above 140 "Near" genius or genius.
120-140 Very superior intelligence.
110-120 Superior intelligence.
90-110 Normal, or average, intelligence.
80- 90 Dullness, rarely classifiable as feeble-mindedness.
70- 80 Border-line deficiency, sometimes classifiable as
dullness, often as feeble-mindedness.
Below 70 Definite feeble-mindedness.
Of the feeble-minded, those between 50 and 70 I Q include most of the
morons (high, middle, and low), those between 20 or 25 and 50 are
ordinarily to be classed as imbeciles, and those below 20 or 25 as
idiots. According to this classification the adult idiot would range up
to about 3-year intelligence as the limit, the adult imbecile would have
a mental level between 3 and 7 years, and the adult moron would range
from about 7-year to 11-year intelligence.
It should be added, however, that the classification of I Q's for the
various sub-grades of feeble-mindedness is not very secure, for the
reason that the exact curves of mental growth have not been worked out
for such grades. As far as the public schools are concerned this does
not greatly matter, as they never enroll idiots and very rarely even the
high-grade imbecile. School defectives are practically all of the moron
and border-line grades, and these it is important teachers should be
able to recognize. The following discussions and illustrative cases will
perhaps give a fairly definite idea of the significance of various
grades of intelligence.[28]
[28] The clinical descriptions to be given are not complete and are
designed merely to aid the examiner in understanding the significance of
intelligence quotients found.
FEEBLE-MINDEDNESS (RARELY ABOVE 75 I Q.) There are innumerable grades of
mental deficiency ranging from somewhat below average intelligence to
profound idiocy. In the literal sense every individual below the average
is more or less mentally weak or feeble. Only a relatively small
proportion of these, however, are technically known as feeble-minded. It
is therefore necessary to set forth the criterion as to what constitutes
feeble-mindedness in the commonly accepted sense of that word.
The definition in most general use is the one framed by the Royal
College of Physicians and Surgeons of London, and adopted by the English
Royal Commission on Mental Deficiency. It is substantially as follows:--
_A feeble-minded person is one who is incapable, because of mental
defect existing from birth or from an early age, (a) of competing on
equal terms with his normal fellows; or (b) of managing himself or his
affairs with ordinary prudence._
Two things are to be noted in regard to this definition: In the first
place, it is stated in terms of social and industrial efficiency. Such
efficiency, however, depends not merely on the degree of intelligence,
but also on emotional, moral, physical, and social traits as well. This
explains why some individuals with I Q somewhat below 75 can hardly be
classed as feeble-minded in the ordinary sense of the term, while others
with I Q a little above 75 could hardly be classified in any other
group.
In the second place, the criterion set up by the definition is not very
definite because of the vague meaning of the expression "ordinary
prudence." Even the expression "competing on equal terms" cannot be
taken literally, else it would include also those who are merely dull.
It is the second part of the definition that more nearly expresses the
popular criterion, for as long as an individual manages his affairs in
such a way as to be self-supporting, and in such a way as to avoid
becoming a nuisance or burden to his fellowmen, he escapes the
institutions for defectives and may pass for normal.
The most serious defect of the definition comes from the lax
interpretation of the term "ordinary prudence," etc. The popular
standard is so low that hundreds of thousands of high grade defectives
escape identification as such. Moreover, there are many grades of
severity in social and industrial competition. For example, most of the
members of such families as the Jukes, the Nams, the Hill Folk, and the
Kallikaks are able to pass as normal in their own crude environment, but
when compelled to compete with average American stock their deficiency
becomes evident. It is therefore necessary to supplement the social
criterion with a more strictly psychological one.
For this purpose there is nothing else as significant as the I Q. All
who test below 70 I Q by the Stanford revision of the Binet-Simon scale
should be considered feeble-minded, and it is an open question whether
it would not be justifiable to consider 75 I Q as the lower limit of
"normal" intelligence. Certainly a large proportion falling between
70 and 75 can hardly be classed as other than feeble-minded, even
according to the social criterion.
_Examples of feeble-minded school children_
_F. C. Boy, age 8-6; mental age 4-2; I Q approximately 50._ From
a very superior home. Has had the best medical care and other
attention. Attended a private kindergarten until rejected
because he required so much of the teacher's time and appeared
uneducable. Will probably develop to about the 6- or 7-year
mental level. High grade imbecile. Has since been committed to a
state institution. Cases as low as F. C. very rarely get into
the public schools.
_R. W. Boy, age 13-10; mental age 7-6; I Q approximately 55._
Home excellent. Is pubescent. Because of age and maturity has
been promoted to the third grade, though he can hardly do the
work of the second. Has attended school more than six years.
Will probably never develop much if any beyond 8 years, and will
never be self-supporting. Low-grade moron.
[Illustration: FIG. 4. DIAMOND DRAWN BY R. W., AGE 13-10; MENTAL
AGE 7-6]
_M. S. Girl, age 7-6; mental age 4-6; I Q 60._ Father a
gardener, home conditions and medical attention fair. Has twice
attempted first grade, but without learning to read more than a
few words. In each case teacher requested parents to withdraw
her. "Takes" things. Is considered "foolish" by the other
children. Will probably never develop beyond a mental level of
8 years.
_R. M. Boy, age 15; mental age 9; I Q 60._ Decidedly superior
home environment and care. After attending school eight years is
in fifth grade, though he cannot do the work of the fourth
grade. Parents unable to teach him to respect property. Boys
torment him and make his life miserable. At middle-moron level
and has probably about reached the limit of his development. Has
since been committed to a state institution.
[Illustration: FIG. 5. WRITING FROM DICTATION. R. M., AGE 15;
MENTAL AGE 9]
_S. M. Girl, age 19-2; mental age 10; I Q approximately 65 (not
counting age beyond 16)._ From very superior family. Has
attended public and private schools twelve years and has been
promoted to seventh grade, where she cannot do the work. Appears
docile and childlike, but is subject to spells of disobedience
and stubbornness. Did not walk until 4 years old. Plays with
young children. Susceptible to attention from men and has to be
constantly guarded. Writing excellent, knows the number
combinations, but missed all the absurdities and has the
vocabulary of an average 10-year-old. The type from which
prostitutes often come.
_R. H. Boy, age 14; mental age 8-4; I Q 65._ Father Irish,
mother Spanish. Family comfortable and home care average. Has
attended school eight years and is unable to do fourth-grade
work satisfactorily. Health excellent and attendance regular.
Reads in fourth reader without expression and with little
comprehension of what is read. Fair skill in number
combinations. Writing and drawing very poor. Cannot use a ruler.
Has no conception of an inch.
R. H. is described as high-tempered, irritable, lacking in
physical activity, clumsy, and unsteady. Plays little. Just
"stands around." Indifferent to praise or blame, has little
sense of duty, plays underhand tricks. Is slow, absent-minded,
easily confused, in thought, never shows appreciation or
interest. So apathetic that he does not hear commands. Voice
droning. Speech poor in colloquial expressions.
Three years later, at age of 17, was in a special class
attempting sixth-grade work. Reported as doing "absolutely
nothing" in that grade. Still sullen, indifferent, and slow in
grasping directions, and lacking in play interests. "No
apperception of anything, but has mastered such mechanical
things as reading (calling the words) and the fundamentals in
arithmetic."
In school work, moral traits, and out-of-school behavior R. H.
shows himself to be a typical case of moron deficiency.
_I. M. Girl, age 14-2; mental age 9; I Q approximately 65._
Father a laborer. Does unsatisfactory work in fourth grade.
Plays with little girls. A menace to the morals of the school
because of her sex interests and lack of self-restraint. Rather
good-looking if one does not hunt for appearances of
intelligence. Mental reactions intolerably slow. Will develop
but little further and will always pass as feeble-minded in any
but the very lowest social environment.
[Illustration: FIG. 6. BALL AND FIELD TEST. I. M., AGE 14-2;
MENTAL AGE 9]
_G. V. Boy, age 10; mental age 6-4; I Q 65._ Father Spanish,
mother English. Family poor but fairly respectable. Brothers and
sisters all retarded. In high first grade. Work all very poor
except writing, drawing, and hand work, in all of which he
excels. Is quiet and inactive, lacks self-confidence, and plays
little. Mentally slow, inert, "thick," and inattentive. Health
fair.
Three years later G. V. was in the low third grade and still
doing extremely poor work in everything except manual training,
drawing, and writing. Is not likely ever to go beyond the fourth
or fifth grade however long he remains in school.
_V. J. Girl, age 11-6; mental age 8; I Q 70._ Has been tested
three times in the last five years, always with approximately
the same result in terms of I Q. Home fair to inferior. Has been
in a special class two years and in school altogether nearly six
years. Is barely able to do third-grade work. Her
feeble-mindedness is recognized by teachers and by other pupils.
Belongs at about middle-moron to high-moron level.
_A. W. Boy, age 9-4; mental age 7; I Q 75._ A year and a half
ago he tested at 6-2. From superior family, brothers of very
superior intelligence. In school three years and has made about
a grade and a half. Has higher I Q than V. J. described above,
but his deficiency is fully as evident. Is generally recognized
as mentally defective. Slyly abstracted one of the pennies used
in the test and slipped it into his pocket. Has caused much
trouble at school by puncturing bicycle tires. High-grade moron.
[Illustration: FIG. 7. DIAMOND DRAWN BY A. W.]
_A. C. Boy, age 12; mental age 8-5; I Q 70._ From Portuguese
family of ten children. Has a feeble-minded brother. Parents in
comfortable circumstances and respectable. A. C. has attended
school regularly since he was 6 years old. Trying unsuccessfully
to do the work of the fourth grade. Reads poorly in the third
reader. Hesitates, repeats, miscalls words, and never gets the
thought. Writes about like a first-grade pupil. Cannot solve
such simple problems as "How many marbles can you buy for ten
cents if one marble costs five cents?" even when he has marbles
and money in his hands. Described by teacher as "mentally slow
and inert, inattentive, easily distracted, memory poor, ideas
vague and often absurd, does not appreciate stories, slow at
comprehending commands." Is also described as "unruly,
boisterous, disobedient, stubborn, and lacking sense of
propriety. Tattles."
Three years later, at age of 15, was in a special class and was
little if any improved. He had, however, learned the mechanics
of reading and had mastered the number combinations.
Deficiencies described as "of wide range." Conduct, however, had
improved. Was "working hard to get on."
A. C. must be considered definitely feeble-minded.
_H. S. Boy, age 11; mental age 8-3; I Q approximately 75._ At
8 years tested at 6. Parents highly educated, father a scholar.
Brother and sister of very superior intelligence. Started to
school at 7, but was withdrawn because of lack of progress.
Started again at 8 and is now doing poor work in the second
grade. Weakly and nervous. Painfully aware of his inability to
learn. During the test keeps saying, "I tried anyway," "It's all
I can do if I try my best, ain't it?" etc. Regarded defective by
other children. Will probably never be able to do work beyond
the fourth or fifth grade and is not likely to develop above the
11-year level, if as high.
[Illustration: FIG. 8. DRAWING DESIGNS FROM MEMORY. H. S.,
AGE 11; MENTAL AGE 8-3]
_I. S. Boy, age 9-6; mental age 7; I Q 75._ German parentage.
Started to school at 6. Now in low second grade and unable to do
the work. Health good. Inattentive, mentally slow and inert,
easily distracted, speech is monotone. Equally poor in reading,
writing, and numbers. I. S. is described as quiet, sullen,
indifferent, lazy, and stubborn. Plays little.
Three years later had advanced from low second to low fourth
grade, but was as poor as ever in his school work. "Miscalls the
simplest words." Moral traits unsatisfactory. May reach sixth or
seventh grade if he remains in school long enough.
I. S. learned to walk at 2 years and to talk at 3.
The above are cases of such marked deficiency that there could be no
disagreement among competent judges in classifying them in the group of
"feeble-minded." All are definitely institutional cases. It is a matter
of record, however, that one of the cases, H. S., was diagnosed by a
physician (without test) as "backward but not a defective." and with the
added encouragement that "the backwardness will be outgrown." Of course
the reverse is the case; the deficiency is becoming more and more
apparent as the boy approaches the age where more is expected of him.
In at least three of the above cases (S. M., I. S., and I. M.) the
teachers had not identified the backwardness as feeble-mindedness. Not
far from 2 children out of 100, or 2 out of 1000, in the average public
school are as defective as some of those just described. Teachers get so
accustomed to seeing a few of them in every group of 200 or 300 pupils
that they are likely to regard them as merely dull,--"dreadfully dull,"
of course,--but not defective.
Children like these, for their own good and that of other pupils, should
be kept out of the regular classes. They will rarely be equal to the
work of the fifth grade, however long they attend school. They will
make a little progress in a well-managed special class, but with the
approach of adolescence, at latest, the State should take them into
custodial care for its own protection.
BORDER-LINE CASES (USUALLY BETWEEN 70 AND 80 I Q). The border-line cases
are those which fall near the boundary generally recognized as such and
the higher group usually classed as normal but dull. They are the
doubtful cases, the ones we are always trying (rarely with success) to
restore to normality.
It must be emphasized, however, that this doubtful group is not marked
off by definite I Q limits. Some children with I Q as high as 75 or even
80 will have to be classified as feeble-minded; some as low as 70 I Q
may be so well endowed in other mental traits that they may manage as
adults to get along fairly well in a simple environment. The ability to
compete with one's fellows in the social and industrial world does not
depend upon intelligence alone. Such factors as moral traits, industry,
environment to be encountered, personal appearance, and influential
relatives are also involved. Two children classified above as
feeble-minded had an I Q as high as 75. In these cases the emotional,
moral, or physical qualities were so defective as to render a normal
social life out of the question. This is occasionally true even with an
I Q as high as 80. Some of the border-line cases, with even less
intelligence, may be so well endowed in other mental traits that they
are capable of becoming dependable unskilled laborers, and of supporting
a family after a fashion.
_Examples of border-line deficiency_
_S. F. Girl, age 17; mental age 11-6; I Q approximately 72
(disregarding age above 16 years)._ Father intelligent; mother
probably high-grade defective. Lives in a good home with aunt,
who is a woman of good sense and skillful in her management of
the girl. S. F. has attended excellent schools for eleven years
and has recently been promoted to the seventh grade. The teacher
admits, however, that she cannot do the work of that grade, but
says, "I haven't the heart to let her fail in the sixth grade
for the third time." She studies very hard and says she wants to
become a teacher! At the time the test was made she was actually
studying her books from two to three hours daily at home. The
aunt, who is very intelligent, had never thought of this girl as
feeble-minded, and had suffered much concern and humiliation
because of her inability to teach her to conduct herself
properly toward men and not to appropriate other people's
property.
[Illustration: FIG. 9. BALL AND FIELD TEST S. F., AGE 17; MENTAL
AGE 11-6]
S. F. is ordinarily docile, but is subject to fits of anger and
obstinacy. She finally determined to leave her home, threatening
to take up with a man unless allowed to work elsewhere. Since
then she has been tried out in several families, but after a
little while in a place she flies into a rage and leaves. She is
a fairly capable houseworker when she tries.
This young woman is feeble-minded and should be classed as such.
She is listed here with the border-line cases simply for the
reason that she belongs to a group whose mental deficiency is
almost never recognized without the aid of a psychological test.
Probably no physician could be found who would diagnose the
case, on the basis of a medical examination alone, as one of
feeble-mindedness.
_F. H. Boy, age 16-6; mental age 11-5; I Q approximately 72
(disregarding age above 16 years)._ Tested for three successive
years without change of more than four points in I Q. Father a
laborer, dull, subject to fits of rage, and beats the boy.
Mother not far from border-line. F. H. has always had the best
of school advantages and has been promoted to the seventh grade.
Is really about equal to fifth-grade work. Fairly rapid and
accurate in number combinations, but cannot solve arithmetical
problems which require any reasoning. Reads with reasonable
fluency, but with little understanding. Appears exceedingly
good-natured, but was once suspended from school for hurling
bricks at a fellow pupil. Played a "joke" on another pupil by
fastening a dangerous, sharp-pointed, steel paper-file in the
pupil's seat for him to sit down on. He is cruel, stubborn, and
plays truant, but is fairly industrious when he gets a job as
errand or delivery boy. Discharged once for taking money.
F. H. is generally called "queer," but is not ordinarily thought
of as feeble-minded. His deficiency is real, however, and it is
altogether doubtful whether he will be able to make a living and
to keep out of trouble, though he is now (at age 20) employed as
messenger boy for the Western Union at $30 per month. This is
considerably less than pick-and-shovel men get in the community
where he lives. Delinquents and criminals often belong to this
level of intelligence.
_W. C. Boy, age 16-8; mental age 12; I Q 75 (disregarding age
above 16 years)._ Father a college professor. All the other
children in the family of unusually superior intelligence. When
tested (four years ago) was trying to do seventh-grade work, but
with little success. Wanted to leave school and learn farming,
but father insisted on his getting the usual grammar-school and
high-school education. Made $25 one summer by raising vegetables
on a vacant lot. In the four years since the test was made he
has managed to get into high school. Teachers say that in spite
of his best efforts he learns next to nothing, and they regard
him as hopelessly dull. Is docile, lacks all aggressiveness,
looks stupid, and has head circumference an inch below normal.
Here is a most pitiful case of the overstimulated backward child
in a superior family. Instead of nagging at the boy and urging
him on to attempt things which are impossible to his inferior
intelligence, his parents should take him out of school and put
him at some kind of work which he could do. If the boy had been
the son of a common laborer he would probably have left school
early and have become a dependable and contented laborer. In a
very simple environment he would probably not be considered
defective.
_C. P. Boy, age 10-2; mental age 7-11; I Q 78._ Portuguese boy,
son of a skilled laborer. One of eleven children, most of whom
have about this same grade of intelligence. Has attended school
regularly for four years. Is in the third grade, but cannot do
the work. Except for extreme stubbornness his social development
is fairly normal. Capable in plays and games, but is regarded as
impossible in his school work. Like his brother, M. P., the next
case to be described, he will doubtless become a fairly reliable
laborer at unskilled work and will not be regarded, in his
rather simple environment, as a defective. From the
psychological point of view, however, his deficiency is real. He
will probably never develop beyond the 11- or 12-year level or
be able to do satisfactory school work beyond the fifth or sixth
grade.
[Illustration: FIG. 10. WRITING FROM DICTATION. C. P., AGE 10-2;
MENTAL AGE 7-11]
_M. P. Boy, age 14; mental age 10-8; I Q 77._ Has been tested
four successive years, I Q being always between 75 and 80.
Brother to C. P. above. In school nearly eight years and has
been promoted to the fifth grade. At 16 was doing poor work in
the sixth grade. Good school advantages, as the father has tried
conscientiously to give his children "a good education."
Perfectly normal in appearance and in play activities and is
liked by other children. Seems to be thoroughly dependable both
in school and in his outside work. Will probably become an
excellent laborer and will pass as perfectly normal,
notwithstanding a grade of intelligence which will not develop
above 11 or 12 years.
[Illustration: FIG. 11. BALL AND FIELD TEST. M. P., AGE 14;
MENTAL AGE 10-8]
What shall we say of cases like the last two which test at high-grade
moronity or at border-line, but are well enough endowed in moral
and personal traits to pass as normal in an uncomplicated social
environment? According to the classical definition of feeble-mindedness
such individuals cannot be considered defectives. Hardly any one would
think of them as institutional cases. Among laboring men and servant
girls there are thousands like them. They are the world's "hewers of
wood and drawers of water." And yet, as far as intelligence is
concerned, the tests have told the truth. These boys are uneducable
beyond the merest rudiments of training. No amount of school instruction
will ever make them intelligent voters or capable citizens in the true
sense of the word. Judged psychologically they cannot be considered
normal.
It is interesting to note that M. P. and C. P. represent the level of
intelligence which is very, very common among Spanish-Indian and Mexican
families of the Southwest and also among negroes. Their dullness seems
to be racial, or at least inherent in the family stocks from which they
come. The fact that one meets this type with such extraordinary
frequency among Indians, Mexicans, and negroes suggests quite forcibly
that the whole question of racial differences in mental traits will have
to be taken up anew and by experimental methods. The writer predicts
that when this is done there will be discovered enormously significant
racial differences in general intelligence, differences which cannot be
wiped out by any scheme of mental culture.
Children of this group should be segregated in special classes and be
given instruction which is concrete and practical. They cannot master
abstractions, but they can often be made efficient workers, able to look
out for themselves. There is no possibility at present of convincing
society that they should not be allowed to reproduce, although from a
eugenic point of view they constitute a grave problem because of their
unusually prolific breeding.
DULL NORMALS (I Q USUALLY 80 TO 90). In this group are included those
children who would not, according to any of the commonly accepted social
standards, be considered feeble-minded, but who are nevertheless far
enough below the actual average of intelligence among races of western
European descent that they cannot make ordinary school progress or
master other intellectual difficulties which average children are equal
to. A few of this class test as low as 75 to 80 I Q, but the majority
are not far from 85. The unmistakably normal children who go much below
this (in California, at least) are usually Mexicans, Indians, or
negroes.
_R. G. Negro boy, age 13-5; mental age 10-6; I Q approximately
80._ Normal in appearance and conduct, but very dull. Is
attempting fifth-grade work in a special class, but is failing.
From a fairly good home and has had ordinary school advantages.
In the examination his intelligence is very even as far as it
goes, but stops rather abruptly after the 10-year tests. Will
unquestionably pass as normal among unskilled laborers, but his
intelligence will never exceed the 12-year level and he is not
likely to advance beyond the seventh grade, if as far.
[Illustration: FIG. 12. BALL AND FIELD. R. G., AGE 13-5, MENTAL
AGE 10-6]
_F. D. Boy, tested at age 10-2; I Q 83, and again at 14-1;
I Q 79._ Mental age in the first test was 8-6 and in the second
test 11. Son of a barber. Father dead; mother capable; makes a
good home, and cares for her children well. At 10 was doing
unsatisfactory work in the fourth grade, and at 12
unsatisfactory work in low sixth. Good-looking, normal in
appearance and social development, and though occasionally
obstinate is usually steady. Any one unacquainted with his poor
school work and low I Q would consider him perfectly normal. No
physical or moral handicaps of any kind that could possibly
account for his retardation. Is simply dull. Needs purely a
vocational training, but may be able to complete the eighth
grade with low marks by the age of 16 or 17.
_G. G. Girl, age 12-4; mental age 10-10; I Q 82._ From average
home. Excellent educational advantages and no physical
handicaps. At 12 years was doing very poor work in fifth grade.
Appearance, play life, and attitude toward other children
normal. Simply dull. Will probably never go beyond the 12- or
13-year level and is not likely to get as far as the high
school.
Those testing 80 and 90 will usually be able to reach the eighth grade,
but ordinarily only after from one to three or four failures. They are
so very numerous (about 15 per cent of the school enrollment) that it is
doubtful whether we can expect soon to have special classes enough to
accommodate all. The most feasible solution is a differentiated course
of study with parallel classes in which every child will be allowed to
make the best progress of which he is capable, without incurring the
risk of failure and non-promotion. The so-called Mannheim system, or
something similar to it, is what we need.
AVERAGE INTELLIGENCE (I Q 90 TO 110). It is often said that the schools
are made for the average child, but that "the average child does not
exist." He does exist, and in very large numbers. About 60 per cent of
all school children test between 90 and 110 I Q, and about 40 per cent
between 95 and 105. That these children are average is attested by their
school records as well as by their I Q's. Our records show that, of more
than 200 children below 14 years of age and with I Q between 95 and 105,
not one was making much more nor much less than average school progress.
Four were two years retarded, but in each case this was due to late
start, illness, or irregular attendance. Children who test close to 90,
however, often fail to get along satisfactorily, while those testing
near 110 are occasionally able to win an extra promotion.
The children of this average group are seldom school problems, as far as
ability to learn is concerned. Nor are they as likely to cause trouble
in discipline as the dull and border-line cases. It is therefore hardly
necessary to give illustrative cases here.
The high school, however, does not fit their grade of intelligence as
well as the elementary and grammar schools. High schools probably enroll
a disproportionate number of pupils in the I Q range above 100. That is,
the average intelligence among high-school pupils is above the average
for the population in general. It is probably not far from 110. College
students are, of course, a still more selected group, perhaps coming
chiefly from the range above 115. The child whose school marks are
barely average in the elementary grades, when measured against children
in general, will ordinarily earn something less than average marks in
high school, and perhaps excessively poor marks in college.
SUPERIOR INTELLIGENCE (I Q 110 TO 120). Children of this group
ordinarily make higher marks and are capable of making somewhat more
rapid progress than the strictly average child. Perhaps most of them
could complete the eight grades in seven years as easily as the average
child does in eight years. They are not usually the best scholars, but
on a scale of excellent, good, fair, poor, and failure they will usually
rank as good, though of course the degree of application is a factor. It
is rare, however, to find a child of this level who is positively
indolent in his school work or who dislikes school. In high school they
are likely to win about the average mark.
Intelligence of 110 to 120 I Q is approximately five times as common
among children of superior social status as among children of inferior
social status; the proportion among the former being about 24 per cent
of all, and among the latter only 5 per cent of all. The group is
made up largely of children of the fairly successful mercantile or
professional classes.
The total number of children between 110 and 120 is almost exactly the
same as the number between 80 and 90; namely, about 15 per cent. The
distance between these two groups (say between 85 and 115) is as great
as the distance between average intelligence and border-line deficiency,
and it would be absurd to suppose that they could be taught to best
advantage in the same classes. As a matter of fact, pupils between
110 and 120 are usually held back to the rate of progress which the
average child can make. They are little encouraged to do their best.
VERY SUPERIOR INTELLIGENCE (I Q 120 TO 140). Children of this group are
better than somewhat above average. They are unusually superior. Not
more than 3 out of 100 go as high as 125 I Q, and only about 1 out of
100 as high as 130. In the schools of a city of average population only
about 1 child in 250 or 300 tests as high as 140 I Q.
In a series of 476 unselected children there was not a single one
reaching 120 whose social class was described as "below average."[29] Of
the children of superior social status, about 10 per cent reached 120 or
better. The 120-140 group is made up almost entirely of children whose
parents belong to the professional or very successful business classes.
The child of a skilled laborer belongs here occasionally, the child of a
common laborer very rarely indeed. At least this is true in the smaller
cities of California among populations made up of native-born Americans.
In all probability it would not have been true in the earlier history of
the country when ordinary labor was more often than now performed by men
of average intelligence, and it would probably not hold true now among
certain immigrant populations of good stock, but limited social and
educational advantages.
[29] In other investigations, however, we have found even brighter
children from very inferior homes. See p. 117 for an example.
What can children of this grade of ability do in school? The question
cannot be answered as satisfactorily as one could wish, for the simple
reason that such children are rarely permitted to do what they can. What
they do accomplish is as follows: Of 54 children (of the 1000 unselected
cases) falling in this group, 12½ per cent were advanced in the
grades two years, approximately 54 per cent were advanced one year,
28 per cent were in the grade where they belonged by chronological age,
and three children, or 5½ per cent, were actually retarded one year.
But wherever located, such children rarely get anything but the highest
marks, and the evidence goes to show that most of them could easily be
prepared for high school by the age of 12 years. Serious injury is done
them by schools which believe in "putting on the brakes."
The following are illustrations of children testing between 130 and 145.
Not all are taken from the 1000 unselected tests. The writer has
discovered several children of this grade as a result of lectures before
teachers' institutes. It is his custom, in such lectures, to ask the
teachers to bring in for a demonstration test the "brightest child in
the city" (or county, etc.). The I Q resulting from such a test is
usually between 130 and 140, occasionally a little higher.
_Examples of very superior intelligence_
_Margaret P. Age 8-10; mental age 11-1; I Q 130._ Father only a
skilled laborer (house painter), but a man of unusual
intelligence and character for his social class. Home care above
average. M. P. has attended school a little less than three
years and is completing fourth grade. Marks all "excellent."
Health perfect. Social and moral traits of the very best. Is
obedient, conscientious, and unusually reliable for her age.
Quiet and confident bearing, but no touch of vanity.
M. P. is known to be related on her father's side to John
Wesley, and her maternal grandfather was a highly skilled
mechanic and the inventor of an important train-coupling device
used on all railroads.
Although she is not yet 9 years old and is completing the fourth
grade, she is still about a grade below where she belongs by
mental age. She could no doubt easily be made ready for high
school by the age of 12.
_J. R. Girl, age 12-9; mental age 16 (average adult); I Q
approximately 130._ Daughter of a university professor. In first
year of high school. From first grade up her marks have been
nearly all of the A rank. For first semester of high school four
of six grades were A, the others B. A wonderfully charming,
delightful girl in every respect. Play life perfectly normal.
_J. R.'s_ parents have moved about a great deal and she has
attended eight different schools. She is two years above grade
in school, but of this gain only one-half grade was made in
school; _the other grade and a half she gained in a little over
a year by staying out of school and working a little each day
under the instruction of her mother_. But for this she would
doubtless now be in the seventh grade instead of in high school.
As it is she is at least a grade below where she belongs by
mental age. Something better than an average college record may
be safely predicted for J. R.
_E. B. Girl, age 7-9; mental age 10-2; I Q 130._ E. B. was
selected by the teachers of a small California city as the
brightest school child in that city (school population about
500). Her parents are said to be unusually intelligent. E. B. is
in the third grade, a year advanced, but her mental level shows
that she belongs in the fourth. The test was made as a
demonstration test in the presence of about 150 teachers, all
of whom were charmed by her delightful personality and keen
responses. No trace of vanity or queerness of any kind. Health
excellent. E. B. ought to be ready for high school at 12; she
will really have the intelligence to do high-school work by 11.
[Illustration: FIG. 13. BALL AND FIELD TEST. E. B., AGE 7-9;
I Q 130]
_L. B. Girl, age 8-6; mental age 11-6; I Q 135._ Tested nearly
three years earlier, age 5-11; mental age 7-6; I Q 127. Daughter
of a university professor. At age of 8-6 was doing very superior
work in the fifth grade. Later, at age of 10-6, is in the
seventh grade with all her marks excellent. Has two sisters who
test almost as high, both completing the eighth grade at barely
12 years of age. L. B. looks rather delicate, and though a
little nervous is ordinarily strong. We have known her since her
early childhood. Like both her sisters, she is a favorite with
young and old, as nearly perfection as the most charming little
girl could be.
_R. S. Boy, age 6-5; mental age 9-6; I Q 148._ When tested at
age 5-2 he had a mental age of 7-6, I Q 142. Father a university
professor. R. S. entered school at exactly 6 years of age, and
at the present writing is 7½ years old and is entering the
third grade. Leads his class in school and takes delight in the
work. Is normal in play life and social traits and is dependable
and thoughtful beyond his years. Should enter high school not
later than 12; could probably be made ready a year earlier, but
as he is somewhat nervous this might not be wise.
_T. F. Boy, age 10-6; mental age 14; I Q 133._ At 13-6 tested at
"superior adult," and had vocabulary of 13,000 (also "superior
adult"). Son of a college professor. Did not go to school till
age of 9 years and was not taught to read till 8½. At this
writing he is 15½ years old and is a senior in high school.
He will complete the high-school course in three and one-half
years with A to B marks, mostly A. Gets his hardest mathematics
lessons in five to ten minutes. Science is his play. When he
discovered Hodge's _Nature Study and Life_ at age of 11 years he
literally slept with the book till he almost knew it by heart.
Since age 12 he has given much time to magazines on mechanics
and electricity. At 13 he installed a wireless apparatus
without other aid than his electrical magazines. He has, for a
boy of his age, a rather remarkable understanding of the
principles underlying electrical applications. He is known by
his playmates as "the boy with a hobby." Stamp collections,
butterfly and moth collections (over 70 different varieties),
seashore collections, and wireless apparatus all show that the
appellation is fully merited. He chooses his hobbies and "rides"
them entirely on his own initiative.
_J. S. Boy, age 8-2; mental age 11-4; I Q 138._ Father was a
lawyer, parents now dead. Is in high fourth grade. Leads his
class. Attractive, healthy, normal-appearing lad. Full of good
humor. Is loving and obedient, strongly attached to his foster
mother (an aunt). Composes verses and fables for pastime. Here
are a couple of verses composed before his eighth birthday. They
are reproduced without change of spelling or punctuation:--
_Christmas_
Hurrah for Christmas
And all it's joy's
That come that day
For girls and boy's.
_Flowers_
Flowers in the garden.
That is all you see
Who likes them best?
That's the honey bee.
J. S. ought to be in the fifth grade, instead of the fourth. He
will easily be able to enter college by the age of 15 if he is
allowed to make the progress which would be normal to a child of
his intelligence. But it is too much to expect that the school
will permit this.
_F. McA. Boy, age 10-3; mental age 14-6; I Q 142._ Father a
school principal. F. is leading his class of 24 pupils in the
high seventh grade. Has received so many extra promotions only
because his father insisted that the teachers allow him to try
the next grade. The dire consequences which they predicted have
never followed. F. is perfectly healthy and one of the most
attractive lads the writer has ever seen. He has the normal play
instincts, but when not at play he has the dignified bearing of
a young prince, although without vanity. His vocabulary is 9000
(14 years), and his ability is remarkably even in all
directions. F. should easily enter college by the age of 15.
[Illustration: FIG. 14. BALL AND FIELD F. McA., AGE 10-3, MENTAL
AGE 14-6]
_E. M. Boy, age 6-11; mental age 10; I Q 145._ Learned to read
at age of 5 without instruction and shortly afterward had
learned from geography maps the capitals of all the States of
the Union. Started to school at 7½. Entered the first grade
at 9 A.M. and had been promoted to the fourth grade by 3 P.M. of
the same day! Has now attended school a half-year and is in the
fifth grade, age 7 years, 8 months. Father is on the faculty of
a university.
E. M. is as superior in personal and moral traits as in
intelligence. Responsible, sturdy, playful, full of humor,
loving, obedient. Health is excellent. Has had no home
instruction in school work. His progress has been perfectly
natural.
[Illustration: FIG. 15. DRAWING DESIGNS FROM MEMORY. E. M.,
AGE 6-11; MENTAL AGE 10, I Q 145
(This performance is satisfactory for year 10)]
The above list of "very superior" children includes only a few of those
we have tested who belong to this grade of intelligence. Every child in
the list is so interesting that it is hard to omit any. We have found
all such children (with one or two exceptions not included here) so
superior to average children in all sorts of mental and moral traits
that one is at a loss to understand how the popular superstitions about
the "queerness" of bright children could have originated or survived.
Nearly every child we have found with I Q above 140 is the kind one
feels, before the test is over, one would like to adopt. If the crime of
kidnaping could ever be forgiven it would be in the case of a child like
one of these.
GENIUS AND "NEAR" GENIUS. Intelligence tests have not been in use long
enough to enable us to define genius definitely in terms of I Q. The
following two cases are offered as among the highest test records of
which the writer has personal knowledge. It is doubtful whether more
than one child in 10,000 goes as high as either. One case has been
reported, however, in which the I Q was not far from 200. Such a
record, if reliable, is certainly phenomenal.
_E. F. Russian boy, age 8-5; mental age 13; I Q approximately
155._ Mother is a university student apparently of very superior
intelligence. E. F. has a sister almost as remarkable as
himself. E. F. is in the sixth grade and at the head of his
class. Although about four grades advanced beyond his
chronological age he is still one grade retarded! He could
easily carry seventh-grade work. In all probability E. F. could
be made ready for college by the age of 12 years without injury
to body or mind. His mother has taken the only sensible course;
she has encouraged him without subjecting him to
overstimulation.
E. F. was selected for the test as probably one of the brightest
children in a city of a third of a million population. He may
not be the brightest in that city, but he is one of the three or
four most intelligent the writer has found after a good deal of
searching. He is probably equaled by not more than one in
several thousand unselected children. How impatiently one waits
to see the fruit of such a budding genius!
_B. F. Son of a minister, age 7-8; mental age 12-4; I Q 160._
Vocabulary 7000 (12 years). This test was not made by the
writer, but by one of his graduate students. The record included
the _verbatim_ responses, so that it was easy to verify the
scoring. There can be no doubt as to the substantial accuracy
of the test. This I Q of 160 is the highest one in the Stanford
University records. B. F. has excellent health, normal play
interests, and is a favorite among his playfellows. Parents had
not thought of him as especially remarkable. He is only in the
third grade, and is therefore about three grades below his
mental age.
[Illustration: FIG. 16. BALL AND FIELD. B. F., AGE 7-8; MENTAL
AGE 12-4; I Q 160
(This is a 12-year performance)]
It is especially noteworthy that not one of the children we have
described with I Q above 130 has ever had any unusual amount or kind of
home instruction. In most cases the parents were not aware of their very
great superiority. Nor can we give the credit to the school or its
methods. The school has in most cases been a deterrent to their
progress, rather than a help. These children have been taught in classes
with average and inferior children, like those described in the first
part of this chapter. Their high I Q is only an index of their
extraordinary cerebral endowment. This endowment is for life. There is
not the remotest probability that any of these children will deteriorate
to the average level of intelligence with the onset of maturity. Such an
event would be no less a miracle (barring insanity) than the development
of an imbecile into a successful lawyer or physician.
IS THE I Q OFTEN MISLEADING? Do the cases described in this chapter give
a reliable picture as to what one may expect of the various I Q levels?
Does the I Q furnish anything like a reliable index of an individual's
general educational possibilities and of his social worth? Are there not
"feeble-minded geniuses," and are there not children of exceptionally
high I Q who are nevertheless fools?
We have no hesitation in saying that there is not one case in fifty in
which there is any serious contradiction between the I Q and the child's
performances in and out of school. We cannot deny the existence of
"feeble-minded geniuses," but after a good deal of search we have not
found one. Occasionally, of course, one finds a feeble-minded person
who is an expert penman, who draws skillfully, who plays a musical
instrument tolerably well, or who handles number combinations with
unusual rapidity; but these are not geniuses; they are not authors,
artists, musicians, or mathematicians.
As for exceptionally intelligent children who appear feeble-minded, we
have found but one case, a boy of 10 years with an I Q of about 125.
This boy, whom we have tested several times and whose development we
have followed for five years, was once diagnosed by a physician as
feeble-minded. His behavior among other persons than his familiar
associates is such as to give this impression. Nothing less than an
entire chapter would be adequate for a description of this case, which
is in reality one of disturbed emotional and social development with
superior intelligence.
It should be emphasized, however, that what we have said about the
significance of various I Q's holds only for the I Q's secured by the
use of the Stanford revision. As we have shown elsewhere (p. 62 _ff._)
the I Q yielded by other versions of the Binet tests are often so
inaccurate as to be misleading.
We have not found a single child who tested between 70 and 80 I Q by the
Stanford revision who was able to do satisfactory school work in the
grade where he belonged by chronological age. Such children are usually
from two to three grades retarded by the age of 12 years. On the other
hand, the child with an I Q of 120 or above is almost never found below
the grade for his chronological age, and occasionally he is one or two
grades above. Wherever located, his school work is so superior as to
suggest strongly the desirability of extra promotions. Those who test
between 96 and 105 are almost never more than one grade above or below
where they belong by chronological age, and even the small displacement
of one year is usually determined by illness, age of beginning school,
etc.
CHAPTER VII
RELIABILITY OF THE BINET-SIMON METHOD
GENERAL VALUE OF THE METHOD. In a former chapter we have noted certain
imperfections of the scale devised by Binet and Simon; namely, that many
of the tests were not correctly located, that the choice of tests was in
a few cases unsatisfactory, that the directions for giving and scoring
the tests were sometimes too indefinite, and that the upper and lower
ranges of the scale especially stood in need of extensions and
corrections. All of these faults have been quite generally admitted. The
method itself, however, after being put to the test by psychologists of
all countries and of all faiths, by the skeptical as well as the
friendly, has amply demonstrated its value. The agreement on this point
is as complete as it is regarding the scale's imperfections.
The following quotations from prominent psychologists who have studied
the method will serve to show how it is regarded by those most entitled
to an opinion:--
There can be no question about the fact that the Binet-Simon
tests do not make half as frequent or half as great errors in
the mental ages (of feeble-minded children) as are included in
gradings based on careful, prolonged general observation by
experienced observers.[30]
[30] Dr. F. Kuhlmann: "The Binet-Simon Tests of Intelligence in Grading
Feeble-Minded Children," in _Journal of Psycho-Asthenics_ (1912),
p. 189.
All of the different authors who have made these researches
(with Binet's method) are in a general way unanimous in
recognizing that the principle of the scale is extremely
fortunate, and all believe that it offers the basis of a most
useful method for the examination of intelligence.[31]
[31] Dr. Otto Bobertag: "L'échelle métrique de l'intelligence," in
_L'Année Psychologique_ (1912), p. 272.
It serves as a relatively simple and speedy method of securing,
by means accessible to every one, a true insight into the
average level of ability of a child between 3 and 15 years of
age.[32]
[32] Dr. Ernest Meumann: _Experimentelle Pädagogik_ (1913), vol. II,
p. 277.
That, despite the differences in race and language, despite the
divergences in school organization and in methods of
instruction, there should be so decided agreement in the
reactions of the children--is, in my opinion, the best
vindication of the _principle_ of the tests that one could
imagine, because this agreement demonstrates that _the tests do
actually reach and discover the general developmental conditions
of intelligence_ (so far as these are operative in
public-school children of the present cultural epoch), and not
mere fragments of knowledge and attainments acquired by
chance.[33]
[33] Dr. W. Stern: _The Psychological Methods of Testing Intelligence._
Translated by Whipple (1913), p. 49.
It is without doubt the most satisfactory and accurate method of
determining a child's intelligence that we have, and so far
superior to everything else which has been proposed that as yet
there is nothing else to be considered.[34]
[34] Dr. H. H. Goddard: "The Binet Measuring Scale of
Intelligence; What it is and How it is to be Used," in _The
Training School Bulletin_ (1912).
The value of the method lies both in the swiftness and the accuracy with
which it works. One who knows how to apply the tests correctly and who
is experienced in the psychological interpretation of responses can in
forty minutes arrive at a more accurate judgment as to a subject's
intelligence than would be possible without the tests after months or
even years of close observation. The reasons for this have already been
set forth.[35] The difference is something like that between measuring a
person's height with a yardstick and estimating it by guess. That this
is not an unfair statement of the case is well shown by the following
candid confession by a psychologist who tested 200 juvenile delinquents
brought before Judge Lindsey's court:--
[35] See this volume, p. 24 _ff._
As a matter of interest I estimated the mental ages of 150 of my
subjects before testing them. In 54 of the estimates the error
was not more than one year in either direction; 70 of the
subjects were estimated too high, the average error being
2 years and 7 months; 26 of the subjects were estimated too low,
the average error being 2 years and 2 months. _These figures
would seem to imply that an estimate with nothing to support it
is wholly unreliable, more especially as many of the estimates
were four or five years wide of the mark._[36]
[36] C. S. Bluemel: "Binet Tests on 200 Delinquents," in _The Training
School Bulletin_ (1915), p. 192. (Italics inserted.)
Criticisms of the Binet method have also been frequently voiced, but
chiefly by persons who have had little experience with it or by those
whose scientific training hardly justifies an opinion. It cannot be too
strongly emphasized that eminence in law, medicine, education, or any
other profession does not of itself enable any one to pass judgment on
the validity of a psychological method.
DEPENDENCE OF THE SCALE'S RELIABILITY ON THE TRAINING OF THE EXAMINER.
On this point two radically different opinions have been urged. On the
one hand, some have insisted that the results of a test made by other
than a thoroughly trained psychologist are absolutely worthless. At the
opposite extreme are a few who seem to think that any teacher or
physician can secure perfectly valid results after a few hours'
acquaintance with the tests.
The dispute is one which cannot be settled by the assertion of opinion,
and, unfortunately, thoroughgoing investigations have not yet been made
as to the frequency and extent of errors made by untrained or partially
trained examiners. The only study of this kind which has so far been
reported is the following:--[37]
[37] Samuel C. Kohs: "The Binet Test and the Training of Teachers," in
_The Training School Bulletin_ (1914), pp. 113-17.
Dr. Kohs gives the results of tests made by 58 inexperienced teachers
who were taking a summer course in the Training School at Vineland. The
class met three times a week for instruction in the use of the Binet
scale. During the first week the students listened to three lectures by
Dr. Goddard. The second week was given over to demonstration testing.
Each student saw four children tested, and attended two discussion
periods of an hour each. During the third, fourth, and fifth weeks each
student tested one child per week, and observed the testing of two
others. The student was allowed to carry the test through in his own
way, but received criticism after it was finished. Twice a week
Dr. Goddard spent an hour with the class, discussing experimental
procedure. The subjects tested were feeble-minded children whose exact
mental ages were already known, and for this reason it was possible to
check up the accuracy of each student's work.
Kohs's table of results for the trial testing of the 174 children
showed:--
(1) That 50 per cent of the work was as exact as any one in the
laboratory could make it;
(2) That in an additional 38 per cent the results were within
three fifths of a year of being exact;
(3) That nearly 90 per cent of the work of the summer students was
sufficiently accurate for all practical purposes;
(4) That the records improved during the brief training so that
during the third week only one test missed the real mental age
by as much as a year.
Since hardly any of these students had had any previous experience with
the Binet tests, Dr. Kohs seems to be entirely justified in his
conclusion that it is possible, in the brief period of six weeks, to
teach people to use the tests with a reasonable degree of accuracy.
What shall we say of the teacher or of the physician who has not even
had this amount of instruction? The writer's experience forces him to
agree with Binet and with Dr. Goddard, that any one with intelligence
enough to be a teacher, and who is willing to devote conscientious study
to the mastery of the technique, can use the scale accurately enough to
get a better idea of a child's mental endowment than he could possibly
get in any other way. It is necessary, however, for the untrained person
to recognize his own lack of experience, and in no case would it be
justifiable to base important action or scientific conclusions upon the
results of the inexpert examiner. As Binet himself repeatedly insisted,
the method is not absolutely mechanical, and cannot be made so by
elaboration of instructions.
It is sometimes held that the examination and classification of backward
children for special instruction should be carried out by the school
physicians. The fact is, however, that there is nothing in the
physician's training to give him any advantage over the ordinary teacher
in the use of the Binet tests. Because of her more intimate knowledge of
children and because of her superior tact and adaptability, the average
teacher is perhaps better equipped than the average physician to give
intelligence tests.
Finally, it should be emphasized that whatever the previous training or
experience of the examiner may have been, his ability to adjust to the
child's personality and his willingness to follow conscientiously the
directions for giving the tests are important factors in his equipment.
INFLUENCE OF THE SUBJECT'S ATTITUDE. One continually meets such queries
as, "How do you know the subject did his best?" "Possibly the child was
nervous or frightened," or, "Perhaps incorrect answers were purposely
given." All such objections may be disposed of by saying that the
competent examiner can easily control the experiment in such a way that
embarrassment is soon replaced by self-confidence, and in such a way
that effort is kept at its maximum. As for mischievous deception, it
would be a poor clinicist who could not recognize and deal with the
little that is likely to arise.
Cautions regarding embarrassment, fatigue, fright, illness, etc. are
given in Chapter IX. Most of the errors which have been reported along
this line are such as can nearly always be avoided by ordinary prudence,
coupled with a little power of observation.[38] We must not charge the
mistakes of untrained and indiscreet examiners against the validity of
the method itself.
[38] See, for example, the rather ludicrous "errors" of the Binet method
reported in _The Psychological Clinic_ for 1915, pp. 140 _ff._ and
167 _ff._
It is possibly true that even if the examiner is tactful and prudent an
unfavorable attitude on the part of the subject may occasionally affect
the results of a test to some extent, but it ought not seriously to
invalidate one examination out of five hundred. The greatest danger is
in the case of a young subject who has been recently arrested and
brought before a court. Even here a little common sense and scientific
insight should enable one to guard against a mistaken diagnosis.
THE INFLUENCE OF COACHING. It might be supposed that after the
intelligence scale had been used with a few pupils in a given school all
of their fellows would soon be apprised of the nature of the tests, and
so learn the correct responses. Experience shows, however, that there is
little likelihood of such influence except in the case of a small
minority of the tests. Experiments in the psychology of testimony have
demonstrated that children's ability to report upon a complex set of
experiences is astonishingly weak. In testing with the Stanford revision
a child is ordinarily given from twenty-four to thirty different tests,
many of which are made up of three or more items. Of the total forty to
fifty items the child is ordinarily able to report but few, and these
not always correctly.
Such tests as memory for sentences and digits, drawing the square and
diamond, reproducing the designs from memory, comparing weights and
lines, describing and interpreting pictures, æsthetic comparison,
vocabulary, dissected sentences, fables, reading for memories, finding
differences and similarities, arithmetical reasoning, and the form-board
test, are hardly subject to report at all. While almost any of the other
tests might, theoretically, be communicated, there is little danger that
many of them will be. It is assumed, of course, that the examiner will
take proper precautions to prevent any of his blanks or other materials
from falling into the hands of those who are to be examined.
The following tests are the ones most subject to the influence of
coaching: Ball and field, giving date, naming sixty words, finding
rhymes, changing hands of clock, comprehension of physical relations,
"induction test," and "ingenuity test."
In several instances we have interviewed children an hour or two after
they had taken the examination, in order to find out how many of the
tests they could recall. A boy of 4 years, after repeated questioning,
could only say: "He showed me some pictures. He had a knife and a penny.
He told me to shut the door." A girl of 3 years could recall nothing
whatever that was intelligible.
An 8-year-old boy said: "He made me tie a knot. He asked me about a ship
and an auto. He wanted me to count backwards. He made me say over some
things, numbers and things."
A boy of 12 years said: "He told me to say all the words I could think
of. He said some foolish things and asked what was foolish [he could not
repeat a single absurdity]. I had to put some blocks together. I had to
do some problems in arithmetic [he could not repeat a single problem].
He read some fables to me. [Asked about the fables he was able to recall
only part of one, that of the fox and the crow.] He showed me the
picture of a field and wanted to know how to find a ball."
It is evident from the above samples of report that the danger of
coaching increases considerably with the age of the children concerned.
With young subjects the danger is hardly present at all; with children
of the upper-grammar grades, in the high school, and most of all in
prisons and reformatories, it must be taken into account. Alternative
tests may sometimes be used to advantage when there is evidence of
coaching on any of the regular tests. It would be desirable to have two
or three additional scales which could be used interchangeably with the
Binet-Simon.
RELIABILITY OF REPEATED TESTS. Will the same tests give consistent
results when used repeatedly with the same subject? In general we
may say that they do. Something depends, however, on the age and
intelligence of the subject and on the time interval between the
examinations.
Goddard proves that feeble-minded individuals whose intelligence has
reached its full development continue to test at exactly the same mental
age by the Binet scale, year after year. In their case, familiarity with
the tests does not in the least improve the responses. At each retesting
the responses given at previous examinations are repeated with only the
most trivial variations. Of 352 feeble-minded children tested at
Vineland, three years in succession, 109 gave absolutely no variation,
232 showed a variation of not more than two fifths of a year, while 22
gained as much as one year in the three tests. The latter, presumably,
were younger children whose intelligence was still developing.
Goddard has also tested 464 public-school children for three successive
years. Approximately half of these showed normal progress or more in
mental age, while most of the remainder showed somewhat less than normal
progress.
Bobertag's retesting of 83 normal children after an interval of
a year gave results entirely in harmony with those of Goddard.
The reapplication of the tests showed absolutely no influence of
familiarity, the correlation of the two tests being almost perfect
(.95). Those who tested "at age" in the first test had advanced, on
the average, exactly one year. Those who tested _plus_ in the first
test advanced in the twelve months about a year and a quarter, as we
should expect those to do whose mental development is accelerated.
Correspondingly, those who tested _minus_ at the first test advanced
only about three fourths of a year in mental age during the
interval.[39]
[39] Otto Bobertag: "Ueber Intelligenz Prüfungen," in _Zeitsch. f.
Angew. Psychol._ (1912), p. 521 _ff._
Our own results with a mixed group of normal, superior, dull and
feeble-minded children agree fully with the above findings. In this case
the two tests were separated by an interval of two to four years, and
the correlation between their results was practically perfect. The
average difference between the I Q obtained in the second test and that
obtained in the first was only 4 per cent, and the greatest difference
found was only 8 per cent.[40]
[40] See _The Stanford Revision and Extension of the Binet-Simon Scale
for Measuring Intelligence_. (Warwick and York, 1916.)
The repetition of the test at shorter intervals will perhaps affect the
result somewhat more, but the influence is much less than one might
expect. The writer has tested, at intervals of only a few days to a few
weeks, 14 backward children of 12 to 18 years, and 8 normal children of
5 to 13 years. The backward children showed an average improvement in
the second test of about two months in mental age, the normal children
an average improvement of little more than three months. No child varied
in the second test more than half a year from the mental age first
secured. On the whole, normal children profit more from the experience
of a previous test than do the backward and feeble-minded.
Berry tested 45 normal children and 50 defectives with the Binet 1908
and 1911 scales at brief intervals. The author does not state which
scale was applied first, but the mental ages secured by the two scales
were practically the same when allowance was made for the slightly
greater difficulty of the 1911 series of tests.[41]
[41] Charles Scott Berry: "A Comparison of the Binet Tests of 1908 and
1911," in _Journal of Educational Psychology_ (1912), pp. 444-51.
We may conclude, therefore, that while it would probably be desirable
to have one or more additional scales for alternative use in testing the
same children at very brief intervals, the same scale may be used for
repeated tests at intervals of a year or more with little danger of
serious inaccuracy. Moreover, results like those set forth above are
important evidence as to the validity of the test method.
INFLUENCE OF SOCIAL AND EDUCATIONAL ADVANTAGES. The criticism has often
been made that the responses to many of the tests are so much subject to
the influence of school and home environment as seriously to invalidate
the scale as a whole. Some of the tests most often named in this
connection are the following: Giving age and sex; naming common objects,
colors, and coins; giving the value of stamps; giving date; naming the
months of the year and the days of the week; distinguishing forenoon and
afternoon; counting; making change; reading for memories; naming sixty
words; giving definitions; finding rhymes; and constructing a sentence
containing three given words.
It has in fact been found wherever comparisons have been made that
children of superior social status yield a higher average mental age
than children of the laboring classes. The results of Decroly and Degand
and of Meumann, Stern, and Binet himself may be referred to in this
connection. In the case of the Stanford investigation, also, it was
found that when the unselected school children were grouped in three
classes according to social status (superior, average, and inferior),
the average I Q for the superior social group was 107, and that of the
inferior social group 93. This is equivalent to a difference of one year
in mental age with 7-year-olds, and to a difference of two years with
14-year-olds.
However, the common opinion that the child from a cultured home does
better in tests solely by reason of his superior home advantages is an
entirely gratuitous assumption. Practically all of the investigations
which have been made of the influence of nature and nurture on mental
performance agree in attributing far more to original endowment than to
environments. Common observation would itself suggest that the social
class to which the family belongs depends less on chance than on the
parents' native qualities of intellect and character.
The results of five separate and distinct lines of inquiry based on the
Stanford data agree in supporting the conclusion that the children of
successful and cultured parents test higher than children from wretched
and ignorant homes for the simple reason that their heredity is better.
The results of this investigation are set forth in full elsewhere.[42]
[42] See _The Stanford Revision and Extension of the Binet-Simon
Measuring Scale of Intelligence_. (Warwick and York, 1916)
It would, of course, be going too far to deny all possibility of
environmental conditions affecting the result of an intelligence test.
Certainly no one would expect that a child reared in a cage and denied
all intercourse with other human beings could by any system of mental
measurement test up to the level of normal children. There is, however,
no reason to believe that _ordinary_ differences in social environment
(apart from heredity), differences such as those obtaining among
unselected children attending approximately the same general type of
school in a civilized community, affects to any great extent the
validity of the scale.
A crucial experiment would be to take a large number of very young
children of the lower classes and, after placing them in the most
favorable environment obtainable, to compare their later mental
development with that of children born into the best homes. No extensive
study of this kind has been made, but the writer has tested twenty
orphanage children who, for the most part, had come from very inferior
homes. They had been in a well-conducted orphanage for from two to
several years, and had enjoyed during that time the advantages of an
excellent village school. Nevertheless, all but three tested below
average, ranging from 75 to 90 I Q.
The impotence of school instruction to neutralize individual differences
in native endowment will be evident to any one who follows the school
career of backward children. The children who are seriously retarded in
school are not normal, and cannot be made normal by any refinement of
educational method. As a rule, the longer the inferior child attends
school, the more evident his inferiority becomes. It would hardly be
reasonable, therefore, to expect that a little incidental instruction in
the home would weigh very heavily against these same native differences
in endowment. Cases like the following show conclusively that it does
not:--
X is the son of unusually intelligent and well-educated parents.
The home is everything one would expect of people of scholarly
pursuits and cultivated tastes. But X has always been
irresponsible, troublesome, childish, and queer. He learned to
walk at 2 years, to talk at 3, and has always been delicate and
nervous. When brought for examination he was 8 years old. He had
twice attempted school work, but could accomplish nothing and
was withdrawn. His play-life was not normal, and other children,
younger than himself, abused and tormented him. The Binet tests
gave an I Q of approximately 75; that is, the retardation
amounted to about two years. The child was examined again three
years later. At that time, after attending school two years, he
had recently completed the first grade. This time the I Q was
73. Strange to say, the mother is encouraged and hopeful because
she sees that her boy is learning to read. She does not seem to
realize that at his age he ought to be within three years of
entering high school.
The forty-minute test had told more about the mental ability of
this boy than the intelligent mother had been able to learn in
eleven years of daily and hourly observation. For X is
feeble-minded; he will never complete the grammar school; he
will never be an efficient worker or a responsible citizen.
Let us change the picture. Z is a bright-eyed, dark-skinned girl
of 9 years. She is dark-skinned because her father is a mixture
of Indian and Spanish. The mother is of Irish descent. With her
strangely mated parents and two brothers she lives in a dirty,
cramped, and poorly furnished house in the country. The parents
are illiterate, and the brothers are retarded and dull, though
not feeble-minded.
It is Z's turn to be tested. I inquire the name. It is familiar,
for I have already tested the two stupid brothers. I also know
her ignorant parents and the miserable cabin in which she lives.
The examination begins with the 8-year tests. The responses are
quick and accurate. We proceed to the 9-year group. There is no
failure, and there is but one minor error. Successes and
failures alternate for a while until the latter prevail. Z has
tested at 11 years. In spite of her wretched home, she is
mentally advanced nearly 25 per cent. By the vocabulary test she
is credited with a knowledge of nearly 6000 words, or nearly
four times as many as X, the boy of cultured home and scholarly
parents, had learned by the age of 8 years.
Five years have passed. When given the test, Z was in the fourth
grade and, as we have already stated, 9 years of age. As a
result of the test she was transferred to the fifth grade. Later
she skipped again and at the age of 14 is a successful student
in the second year of high school. To assay her intelligence and
determine its quality was a task of forty-five minutes.
The above cases, each of which could be paralleled by many others which
we have found, will serve to illustrate the fact that exceptionally
superior endowment is discoverable by the tests, however unfavorable the
home from which it comes, and that inferior endowment cannot be
normalized by all the advantages of the most cultured home. Quoting
again from Stern, "The tests actually reach and discover the general
developmental conditions of intelligence, and not mere fragments of
knowledge and attainments acquired by chance."
PART II
GUIDE FOR THE USE OF THE STANFORD REVISION AND EXTENSION