is placed before the child, out of which several square holes have
been cut. These cut-out pieces are mounted on little blocks, and there
are other similar blocks with more or less irrelevant objects pictured
on them. The child must select from the whole collection of little
blocks the one that belongs in each hole in the picture. The better
his understanding of the picture, the better his selection.
Group Testing
The tests so far described, because they have to be given to each
subject individually, require a great deal of time from the trained
examiner, and tests are also needed which can be given to a whole
group of people at once. For persons who can read printed directions,
a group test can easily be conducted, though much preliminary labor is
necessary in selecting and standardizing the questions used. Group
testing of foreigners, illiterates, and young children is more
difficult, but has been accomplished, the directions being conveyed
orally or by means of pantomime.
The first extensive use of group intelligence tests was made in the
American Army during the Great War. A committee of the American
Psychological Association prepared and standardized the tests, and
persuaded the Army authorities to let them try them out in the camps.
So successful were these tests--when supplemented, in doubtful cases,
by individual tests--that they were adopted in the receiving {277}
camps; and they proved very useful both in detecting those individuals
whose intelligence was too low to enable them to learn the duties of a
soldier, and those who, from high intelligence, could profitably be
trained for officers.
The "Alpha test", used on recruits who could read, consisted of eight
pages of questions, each page presenting a different type of problem
for solution. On the first page were rows of circles, squares, etc.,
to which certain things were to be done in accordance with spoken
commands. The subject had to attend carefully to what he was told to
do, since he was given each command only once, and some of the
commands called for rather complicated reactions. The second page
consisted of arithmetical problems, ranging from very simple at the
top of the page to more difficult ones below, though none of them went
into the more technical parts of arithmetic. One page tested the
subject's information on matters of common knowledge; and another
called for the selection of the best of three reasons offered for a
given fact, as, for example, "Why is copper used for electric wires?
Because--it is mined in Montana--it is a good conductor--it is the
cheapest metal." Another page presented disarranged sentences (as,
"wet rain always is", or "school horses all to go"), to be put
straight mentally, and indicated on the paper as true or false.
Many group tests are now in use, and among them some performance
tests. In the latter, pictures are often employed; sometimes the
subject has to complete the picture by drawing in a missing part,
sometimes he has to cancel from the picture a part that is
superfluous. He may have to draw a pencil line indicating the shortest
path through a maze, or he may have to continue a series of marks
which starts off according to a definite plan. The problems set him
under each class range from very easy to fairly difficult.
{278}
Some Results of the Intelligence Tests
The principal fact discovered by use of standardized intelligence
tests is that the tests serve very well the purpose for which they
were intended. In expert hands they actually give a fairly reliable
measure of the individual's intelligence. They have located the
trouble in the case of many a backward school child, whose
intelligence was too low to enable him to derive much benefit from the
regular school curriculum. His schooling needed to be adjusted to his
intelligence so as to prepare him to do what he was constitutionally
able to do.
On the other hand, it sometimes happens that a child who is
mischievous and inattentive in school, and whose school work is rather
poor, tests high in intelligence, the trouble with him being that the
work set him is below his mental level and therefore unstimulating.
Such children do better when given more advanced work. The
intelligence tests are proving of great service in detecting boys and
girls of superior intelligence who have been dragging along, forming
lazy habits of work, and not preparing for the kind of service that
their intelligence should enable them to give.
Some results obtained by the "Alpha test" are given in the following
table, and in the diagram which restates the facts of the table in
graphic form. The Alpha test included 212 questions in all, and a
correct answer to any question netted the subject one point. The
maximum score was thus 212 points, a mark which could only be obtained
by a combination of perfect accuracy and very rapid work (since only a
limited time was allowed for each page of the test). Very seldom does
even a very bright individual score over 200 points. The table shows
the approximate per cent, of individuals scoring between certain
limits; thus, {279} of men drafted into the Army, approximately 8 per
cent. scored below 15 points, 12 per cent. scored from 16 to 29
points, etc. Of college freshmen, practically none score below 76
points, 1 per cent. score from 76 to 89 points, etc.
Per cent. of Per cent. of
drafted men college freshmen
making these making these
Scores Scores
Scores
0-14 points 3 0
15-29 12 0
30-44 15 0
45-59 16 0
60-74 13 0
75-89 11 1
90-104 9 4
105-119 7 8
120-134 6 14
135-149 4 23
150-164 2 24
165-179 1.3 13
180-194 0.5 7
195-212 0.2 1
----- ---
100 100
The "drafted men", consisting of men between the ages of twenty-one
and thirty-one, fairly represent the adult male white population of
the country, except in two respects. Many able young men were not
included in the draft, having previously volunteered for officers'
training camps or for special services. Had they been included, the
percentages making the higher scores would have gone up slightly. On
the other hand, many men of very low intelligence never reached the
receiving camps at all, being inmates of institutions for the
feebleminded or excluded from the draft because of known mental
deficiency; and, of those who reached {280} the camps, many, being
illiterate, did not take the Alpha test. It is for this reason that
the graph for drafted men stops rather short at the lower end; to
picture fairly the distribution of intelligence, it should taper off
to the left, beyond the zero of the Alpha test.
[Illustration: Fig. 46.--Distribution of the scores of drafted men,
and also of college freshmen, in the Alpha test. The height of the
broken line above the base line is made proportional to the percent of
the group that made the score indicated just below along the base
line. (Figure text: army median--65, freshman median--150)]
College freshmen evidently are, as they should be, a highly selected
group in regard to intelligence. The results obtained at different
colleges differ somewhat, and the figures here given represent an
approximate average of results obtained at several colleges of high
standing. The median {281} score for freshmen has varied, at different
colleges, from 140 to 160 points.
[Footnote: The "median" is a statistical measure very similar to the
average; but, while the average score would be obtained by adding
together the scores of all the individuals and dividing the sum by
the number of individuals tested, the median is obtained by
arranging all the individual scores in order, from the lowest to the
highest, and then counting off from either end till the middle
individual is reached; his score is the median. (If the number of
individuals tested is an even number, there are two middle
individuals, and the point midway between them is taken as the
median.) Just as many individuals are below the median as above it.
The median is often preferred to the average in psychological work,
not only because it is more easily computed, but because it is less
affected by the eccentric or unusual performances of a few
individuals, and therefore more fairly represents the whole
population.]
It will be noticed in the graph that none of the freshmen score as low
as the median of the drafted men. All of the freshmen, in fact, lie
well above the median for the general population. A freshman who
scores below 100 points finds it very difficult to keep up in his
college work. Sometimes, it must be said, a freshman who scores not
much over 100 in the test does very well in his studies, and sometimes
one who scores very high in the test has to be dropped for poor
scholarship, but this last is probably due to distracting interests.
No such sampling of the adult female population has ever been made as
was afforded by the draft, and we are not in a position to compare the
average adult man and woman in regard to intelligence. Boys and girls
under twelve average almost the same, year by year, according to the
Binet tests. In various other tests, calling for quick, accurate work,
girls have on the average slightly surpassed boys of the same age, but
this may result from the fact that girls mature earlier than boys;
they reach adult height earlier, and perhaps also adult intelligence.
College women, in the Alpha test, score on the average a few points
below college men, but this, on the other hand, may be due to the fact
that the Alpha test, being prepared for men, includes a few questions
that lie rather outside the usual range of women's interests. On the
whole, tests have given very little evidence of any significant
difference between the general run of intelligence in the two sexes.
Limitations of the Intelligence Tests
Tests of the Binet or Alpha variety evidently do not cover the whole
range of intelligent behavior. They do not test {282} the ability to
manage carpenter's or plumber's tools or other concrete things, they
do not test the ability to manage people, and they do not reach high
enough to test the ability to solve really big problems.
Regarding the ability to manage concrete things, we have already
mentioned the performance tests, which provide a necessary supplement
to the tests that deal in ideas expressed in words. It is an
interesting fact that some men whose mental age is below ten,
according to the Binet tests, nevertheless have steady jobs, earn good
wages, and get on all right in a simple environment. There are many
others, with a mental age of ten or eleven, who cannot master the
school work of the upper grades, and yet become skilled workmen or
even real artists. Now, it takes mentality to perform skilled or
artistic work; only, the mentality is different from that demanded by
what we call "intellectual work".
Managing people requires tact and leadership, which are obviously
mental traits, though not easily tested. It is seldom that a real
leader of men scores anything but high in the intelligence tests, but
it more often happens that an individual who scores very high in the
tests has little power of leadership. In part this is a matter of
physique, or of temperament, rather than of intelligence, but in part
it is a matter of _understanding_ people and seeing how they can be
influenced and led.
Though the intelligence tests deal with "ideas", they do not, as so
far devised, reach up to the great ideas nor make much demand on the
superior powers of the great thinker. If we could assemble a group of
the world's great authors, scientists and inventors, and put them
through the Alpha test, it is probable that they would all score high,
but not higher than the upper ten per cent, of college freshmen. Had
their IQ's been determined when they were children, {283} probably all
would have measured over 180 and some as high as 200, but the tests
would not have distinguished these great geniuses from the gifted
child who is simply one of a hundred or one of a thousand.
The Correlation of Abilities
There is no opposition between "general intelligence", as measured by
the tests, and the abilities to deal with concrete things, with
people, or with big ideas. Rather, there is a considerable degree of
correspondence. The individual who scores high in the intelligence
tests is likely, but not certain, to surpass in these respects the
individual who scores low in the tests. In technical language, there
is a "positive correlation" between general intelligence and ability
to deal with concrete things, people and big ideas, but the
correlation is not perfect.
_Correlation_ is a statistical measure of the degree of
correspondence. Suppose, for an example, we wish to find out how
closely people's weights correspond to their heights. Stand fifty
young men up in single file in order of height, the tallest in front,
the shortest behind. Then weigh each man, and shift them into the
order of their weights. If no shifting whatever were needed, the
correlation between height and weight would be perfect. Suppose the
impossible, that the shortest man was the heaviest, the tallest the
lightest, and that the whole order needed to be exactly reversed; then
we should say that the correlation was perfectly inverse or negative.
Suppose the shift from height order to weight order mixed the men
indiscriminately, so that you could not tell _anything_ from a man's
position in the height order as to what his position would be in the
weight order; then we should have "zero correlation". The actual
result, however, would be that, while the height order would be {284}
somewhat disturbed in shifting to the weight order, it would not be
entirely lost, much less reversed. That is, the correlation between
height and weight is positive but not perfect.
Statistics furnishes a number of formulae for measuring correlations,
formulae which agree in this, that perfect positive correlation is
indicated by the number + 1, perfect negative correlation by the
number - 1, and zero correlation by 0. A correlation of +.8 indicates
close positive correspondence, though not perfect correspondence; a
correlation of +.3 means a rather low, but still positive,
correspondence; a correlation of -.6 means a moderate tendency towards
inverse relationship.
The correlation between two good intelligence tests, such as the Binet
and the Alpha, comes out at about +.8, which means that if a fair
sample of the general population, ranging from low to high
intelligence, is given both tests, the order of the individuals as
measured by the one test will agree pretty closely with the order
obtained with the other test. The correlation between a general
intelligence test and a test for mechanical ability is considerably
lower but still positive, coming to about +.4. Few if any real
negative correlations are found between different abilities, but low
positive or approximately zero correlations are frequent between
different, rather special abilities.
In other words, there is no evidence of any antagonism between
different sorts of ability, but there is plenty of evidence that
different special abilities may have little or nothing in common.
[Footnote]
Possibly some readers would like to see a sample of the
statistical formulae by which correlation is measured. Here is one
of the simplest. Number the individuals tested in their order as
given by the first test, and again in their order as given by the
second test, and find the difference between each individual's two
rank numbers. If an individual who ranks no. 5 in one test ranks no.
12 in the other, the difference in his rank numbers is 7. Designate
this difference by the letter D. and the whole number of individuals
tested by n. Square each D, and get the sum of all the squares,
calling this sum "sum of D2[squared]". Then the correlation is given
by the formula,
1 - ( ( 6 X sum of D[squared] ) / (n x ( n[squared] - 1)) )
As an example in the use of this formula, take the following:
Individuals Rank of each Rank of each D D[squared]
tested individual in individual in
first test second test
Albert 3 5 2 4
George 7 6 1 1
Henry 5 3 2 4
James 2 1 1 1
Stephen 1 4 3 9
Thomas 4 2 2 4
William 6 7 1 1
n = 7
sum of D[squared] = 24
n[squared] - 1 = 48
6 x sum of D[squared] = 144
6 x sum of D[squared] / n ( n[squared] - 1 )
= 1 - 144/(7 x 48)
= +.57
In order to get a full and true measure of the correlation between
two tests, the following precautions are necessary:
(1) The _same individuals_ must be given both tests.
(2) The number of individuals tested must be as great as 15 or 20,
preferably more.
(3) The individuals should be a fair sample of the population in
regard to the abilities tested; they should not be so selected as to
represent only a small part of the total range of ability.
(4) The tests should be thorough enough to determine each
individual's rank in each test, with a high degree of certainty.
Sloppy testing gives a correlation nearer zero than it should be,
because it "pies" the true orders to some extent.
[End footnote]
{285}
General Factors in Intelligence
If now we try to analyze intelligence and see in what it consists, we
can best proceed by reviewing the intelligence tests, and asking how
it is that an individual succeeds in them. Passing the tests is a very
specific instance of {286} intelligent behavior, and an analysis of
the content of the tests should throw some light on the nature of
intelligence.
The first thing that strikes the eye in looking over the tests is that
they call for so many different reactions. They call on you to name
objects, to copy a square, to tell whether a given statement is true
or false, to tell wherein two objects are alike or different. The
first impression, then, is that intelligence consists simply in doing
a miscellaneous lot of things and doing them right.
But can we not state in more general terms how the individual who
scores high in the tests differs from one who scores low? If you
survey the test questions carefully, you begin to see that the person
who passes them must possess certain general characteristics, and that
lack of these characteristics will lead to a low score. We may speak
of these characteristics as "general factors" in intelligent behavior.
First, the tests evidently require the use of past experience. They
call, not for instinctive reactions, but for previously learned
reactions. Though the Binet tests attempt to steer clear of specific
school knowledge, they do depend upon knowledge and skill picked up by
the child in the course of his ordinary experience. They depend on the
ability to learn and remember. One general factor in intelligence is
therefore _retentiveness_.
But the tests do not usually call for simple memory of something
previously learned. Rather, what has been previously learned must be
applied, in the test, to a more or less novel problem. The subject is
asked to do something a little different from anything he has
previously done, but similar enough so that he can make use of what he
has learned. He has to _see the point_ of the problem now set him, and
to _adapt_ what he has learned to this novel situation. Perhaps
"seeing the point" and "adapting oneself to {287} a novel situation"
are to be held apart as two separate general factors in intelligence,
but on the whole it seems possible to include both under the general
head, _responsiveness to relationships_, and to set up this
characteristic as a second general factor in intelligence.
In the form board and picture completion tests, this responsiveness to
relationships comes out clearly. To succeed in the form board, the
subject must respond to the likeness of shape between the blocks and
their corresponding holes. In picture completion, he must see what
addition stands in the most significant relationship to the total
picture situation. In telling how certain things are alike or
different, he obviously responds to relationships; and so also in
distinguishing between good and poor reasons for a certain fact. This
element of response to relationships occurs again and again in the
tests, though perhaps not in the simplest, such as naming familiar
objects.
Besides these two intellectual factors in intelligent behavior, there
are certain moral or impulsive factors. One is _persistence_, which is
probably the same thing as the mastery or self-assertive instinct. The
individual who gives up easily, or succumbs easily to distraction or
timidity, is at a disadvantage in the tests or in any situation
calling for intelligent behavior.
But, as we said before, in discussing the instincts, excessive
stubbornness is a handicap in meeting a novel situation, which often
cannot be mastered by the first mode of response that one makes to it.
Some giving up, some _submissiveness_ in detail along with persistence
in the main effort, is needed. The too stubborn young child may waste
a lot of time trying with all his might to force the square block into
the round hole, and so make a poorer score in the test, than if he had
given up his first line of attack and tried something else.
Intelligent behavior must perforce {288} often have something of the
character of "trial and error", and trial and error requires both
persistence in the main enterprise and a giving up here in order to
try again there.
Finally, the instinct of _curiosity_ or exploration is evidently a
factor in intelligence. The individual who is stimulated by novel
things to explore and manipulate them will amass knowledge and skill
that can later be utilized in the tests, or in intelligent behavior
generally.
Special Aptitudes
We distinguish between the general factors in intelligence, just
mentioned, and special aptitudes for dealing with colors, forms,
numbers, weights etc. A special aptitude is a specific responsiveness
to a certain kind of stimulus or object. The special aptitudes are
factors in intelligent behavior--as we may judge from the content of
the intelligence tests--only, the tests are so contrived as not to
depend too much on any one or any few of the special aptitudes.
Arithmetical problems alone would not make a fair test for
intelligence, since they would lay undue stress on the special
aptitude for number; but it is fair enough to include them along with
color naming, weight judging, form copying, and word remembering, and
so to give many special aptitudes a chance to figure in the final
score.
There are tests in existence for some special aptitudes: tests for
color sense and color matching, for musical ability, for ability in
drawing, etc.; but as yet we have no satisfactory list of the special
aptitudes. They come to light when we compare one individual with
another, or one species with another. Thus, while man is far superior
to the dog in dealing with colors, the dog is superior in dealing with
odors. Man has more aptitude for form, but some animals are fully his
equal in sense of location and ability to find {289} their way. Man is
far superior in dealing with numbers and also with tools and
mechanical things. He is superior in speech, in sense of rhythm, in
sense of humor, in sense of pathos. Individual human beings also
differ markedly in each of these respects. They differ in these
special directions as well as in the "general factors" of
intelligence.
Heredity of Intelligence and of Special Aptitudes
Let us now return to the question raised at the very outset of the
chapter, whether or not intelligence is a native trait. We then said
that the differing intelligence of different species of animals must
be laid to their native constitutions, but left the question open
whether the differing intelligence of human individuals was a matter
of heredity or of environment.
Intelligence is of course quite different from instinct, in that it
does not consist in ready-made native reactions. The intelligence of
an individual at any age depends on what he has learned previously.
But the factors in intelligent behavior--retentiveness, responsiveness
to relationships, persistence, etc.--may very well be native traits.
But what _evidence_ is there that the individual's degree of
intelligence is a native characteristic, like his height or color of
hair? The evidence is pretty convincing to most psychologists.
First, we have the fact that an individual's degree of intelligence is
an inherent characteristic, in the sense that it remains with him from
childhood to old age. Bright child, bright adult; dull child, dull
adult. That is the rule, and the exceptions are not numerous enough to
shake it. Many a dull child of well-to-do parents, in spite of great
pains taken with his education, is unable to escape from his inherent
limitations. The intelligence quotient remains fairly {290} constant
for the same child as he grows up, and stands for an inherent
characteristic of the individual, namely, the rate at which he
acquires knowledge and skill. Give two children the same environment,
physical and social, and you will see one child progress faster than
the other. Thus, among children who grow up in the same community,
playing together and going to the same schools, the more rapid mental
advance of some than of others is due to differences in native
constitution, and the IQ gives a measure of the native constitution in
this respect. There are exceptions, to be sure, depending on physical
handicaps such as deafness or disease, or on very bad treatment at
home, but in general the IQ can be accepted as representing a fact of
native constitution.
Another line of evidence for the importance of native constitution in
determining degrees of intelligence comes from the study of mental
resemblance among members of the same family. Brothers or sisters test
more alike than children taken at random from a community, and twins
test more alike than ordinary brothers and sisters. Now, as the
physical resemblance of brothers or sisters, and specially of twins,
is accepted as due to native constitution, we must logically draw the
same conclusion from their mental resemblance.
The way feeble-mindedness runs in families is a case in point. Though,
in exceptional instances, mental defect arises from brain injury at
the time of birth, or from disease (such as cerebrospinal meningitis)
during early childhood, in general it cannot be traced to such
accidents, but is inherent in the individual. Usually mental defect or
some similar condition can be found elsewhere in the family of the
mentally defective child; it is in the family stock. When both parents
are of normal intelligence and come from families with no mental
abnormality in any ancestral line, it is practically unknown that they
should have a feeble-minded {291} child; but if mental deficiency has
occurred in some of the ancestral lines, an occasional feeble-minded
child may be born even of parents who are themselves both normal. If
one parent is normal and the other feeble-minded, some of the children
are likely to be normal and others feeble-minded; but if both parents
are feeble-minded, it is said that all the children are sure to be
feeble-minded or at least dull.
These facts regarding the occurrence of feeble-mindedness cannot be
accounted for by environmental influences, especially the fact that
some children of the same family may be definitely feeble-minded and
others normal. We must remember that children of the same parents need
not have precisely similar native constitutions; they are not always
alike in physical traits such as hair color or eye color that are
certainly determined by native constitution.
The special aptitudes also run in families. You find musical families
where most of the children take readily to music, and other families
where the children respond scarcely at all to music, though their
general intelligence is good enough. You find a special liking and
gift for mathematics cropping out here and there in different
generations of the same family. No less significant is the fact that
children of the same family show ineradicable differences from one
another in such abilities. In one family were two brothers, the older
of whom showed much musical ability and came early to be an organist
and composer of church music; while the younger, possessing
considerable ability in scholarship and literature, was never able to
learn to sing or tell one tune from another. Being a clergyman, he
desired very much to be able to lead in singing, but he simply could
not learn. Such obstinate differences, persisting in spite of the same
home environment, must depend on native constitution.
Native constitution determines mental ability in two respects. It
fixes certain limits which the individual cannot {292} pass, no matter
how good his environment, and no matter how hard he trains himself;
and, on the positive side, it makes the individual responsive to
certain stimuli, and so gives him a start towards the development of
intelligence and of special aptitudes.
Intelligence and the Brain
There is certainly some connection between the brain and intelligent
behavior. While the spinal cord and brain stem vary according to the
size of the body, and the cerebellum with the motility of the species
of animal, the size of the cerebrum varies more or less closely with
the intelligence of the species. It does vary also with bodily size,
as illustrated by the whale and elephant, which have the largest
cerebrum of all animals, including man. But the monkey, which shows
more intelligence than most animals, has also a very large cerebrum
for his size of body; and the chimpanzee and gorilla, considerably
surpassing the ordinary monkeys in intelligence, have also a much
larger cerebrum. The cerebrum of man, in proportion to the size of his
body, far surpasses that of the chimpanzee or gorilla.
The cerebrum varies considerably in size from one human individual to
another. In some adults it is twice as large as in others, and the
question arises whether greater intelligence goes with a larger brain.
Now, it appears that an extremely small cerebrum spells idiocy; not
all idiots have small brains, but all men with extremely small brains
are idiots. The brain weight of quite a number of highly gifted men
has been measured in post-mortem examination, and many of these gifted
men have had a very large cerebrum. On the whole, the gifted
individual seems to have a large brain, but there are exceptions, and
the relationship between brain size and intelligence cannot be very
close. Other factors must enter, one factor being undoubtedly the
fineness {293} of the internal structure of the cortex. Brain function
depends on dendrites and end-brushes, forming synapses in the cortex,
and such minute structures make little impression on the total brain
weight.
While intelligence is related to the cerebrum as a whole, rather than
to any particular "intelligence center", there is some likelihood that
the special aptitudes are related to special parts of the cortex,
though it must be admitted that few aptitudes have as yet been
localized. The pretended localizations of phrenology are all wrong.
But we do know that each sense has its special cortical area, and that
adjacent to these sensory areas are portions of the cortex intimately
concerned in response to different classes of complex stimuli. Near
the auditory center the cortex is concerned in recognizing spoken
words, and in following music; near the visual center it is concerned
in recognizing printed words, in recognizing seen objects, in finding
one's way by the sense of sight, etc. These special aptitudes thus
have a fairly definite cortical localization, and possibly others have
also.
Examined microscopically, the cortex shows differences of structure in
different parts, and to the structural differences probably correspond
differences of function. Now it is practically impossible that such a
function as attention or memory should have any localized cortical
center, for these are general functions. The instincts are specialized
enough to have local centers, but none have so far been localized.
What has been localized is of the nature of special aptitudes.
{294}
EXERCISES
1. Outline the chapter.
2. Pick out the true statements from the following list:
(a) Man is the most intelligent of animals.
(b) Intelligence depends on the development of the cerebellum.
(c) It has not been found possible to use any single
performance as a reliable index of intelligence.
(d) Children of different mental ages may have the same IQ.
(e) A child with a mental age of 10 years can do all the tests
for 10 years and below, but none of those for the higher ages.
(f) The intelligence tests depend wholly on accurate response
and not at all on speed of reaction.
(g) If intelligence tests depended upon previous training, they
could not be measures of native intelligence.
(h) High correlation between the test scores of brothers and
sisters is a fact that tends to indicate the importance of
heredity in determining intelligence.
(i) The "general factors" in intelligence are the same as the
instincts.
(j) Feeble-minded individuals include all those who are below
the average intelligence.
3. It is found that eminent men very often have eminent brothers,
uncles and cousins. How would this fact be explained?
4. It is also found that the wives of eminent men often have eminent
relatives. How would this fact be explained?
5. How could it happen that a boy of 9, in the third school grade,
with an IQ of 140, should be mischievous and inattentive? What
should be done with him?
6. If a boy of 12, by industrious work, does pretty well in the
fourth grade, why should we not accept the teacher's estimate of
him as a "fairly bright boy"?
7. How might the brain of an idiot be underdeveloped, aside from
the matter of the number of nerve cells in the cortex?
8. Can it be that high intelligence is a disadvantage in any form
of industrial work, and, if so, how?
9. Show how "general intelligence" and "special aptitudes" may
work together to give success in some special line of work.
{295}
REFERENCES
For the Binet tests and some results obtained by their use, see Louis
M. Terman, _The Measurement of Intelligence_, 1916.
The group tests used in the American Army during the War are described
in detail In Vol. 15 of the _Memoirs of the National Academy of
Sciences_, 1921, edited by Robert M. Yerkes. This large book describes
the work of preparing and standardizing the tests, and also gives some
results bearing on the Intelligence of different sections of the
population. Some of the interesting results appear on pp. 507, 522,
528, 537, 693, 697, 705, 732, 743, 799, 815, 819, 829, 856 and 869.
For briefer treatments of the subject, see Walter S. Hunter's _General
Psychology_, 1919, pp. 36-58, and W. B. Pillsbury's _Essentials of
Psychology_, 2nd edition, 1920, pp. 388-407.
For the poor results obtained in attempting to judge intelligence from
photographs, see an illustrated article by Rudolph Pintner, in the
_Psychological Review_ for 1918, Vol. 25, pp. 286-296.
For a study of one of the special aptitudes, see C. E. Seashore's
_Psychology of Musical Talent_, 1919.
For a comprehensive survey of test methods and results, see the two
volumes of Whipple's _Manual of Mental and Physical Tests_, 2nd
edition, 1914, 1915.
{296}
CHAPTER XIII
LEARNING AND HABIT FORMATION
THE DEPENDENCE OF ACQUIRED REACTIONS UPON INSTINCT AND REFLEX ACTION,
AND THE MODIFICATION OF NATIVE REACTIONS BY EXPERIENCE AND TRAINING.
Already, in considering intelligence, we have partially rounded the
corner from native to acquired traits, and now, fairly around the
corner, we see ahead of us a long straight stretch of road. For there
is much to say regarding acquired traits and regarding the process of
acquisition. All knowledge is acquired, the whole stock of ideas, as
well as motor skill, and there are acquired motives in addition to the
native motive forces that we called instincts, and acquired likes and
dislikes in addition to those that are native; so that, all in all,
there are thousands on thousands of acquired reactions, and the daily
life of the adult is made up of these much more than of strictly
native reactions.
It will take us several chapters to explore this new territory that
now lies before us, a chapter on acquiring motor habits and skill, a
chapter on memory, a chapter on acquired mental reactions, and a
chapter devoted to the general laws that hold good in this whole
field. Our general plan is to proceed from the simple to the complex,
generalizing to some extent as we go, but leaving the big
generalizations to the close of the discussion, where we shall see
whether the whole process of acquiring reactions of all sorts cannot
be summed up in a few general laws of acquisition, or "laws of
association" as they are traditionally called. On reaching that {297}
goal, the reader may well come back, with the general laws in mind,
and see how well they fit in detail all the instances of acquired
responses that we are about to describe. We might have begun by
stating the general laws, but on the whole it will be better to
proceed "inductively", beginning with the observed facts and working
up to the general laws.
Acquired Reactions Are Modified Native Reactions
Though we have "turned a corner" in passing from native traits to
acquired, it would be a mistake to suppose we had left what is native
altogether behind. It would be a mistake to suppose that the
individual outgrew and left behind his native reactions and acquired
an entirely new outfit. The reactions that he acquires--or _learns_,
as we speak of acquisition in the sphere of reactions--develop out of
his native reactions. Consider this: how is the individual ever going
to learn a reaction? Only by reacting. Without native reactions, he
would be entirely inactive at the outset, and would never make a start
towards any acquisition. His acquired reactions, then, are his native
reactions modified by use.
The vast number of motor acts that the individual acquires are based
upon the reflexes. They are modified reflexes. The simplest kind of
modification is the mere _strengthening_ of an act by exercise. By his
reflex breathing and crying, the new-born baby exercises his lungs and
breathing muscles and the nerve centers that control them, with the
result that his breathing becomes more vigorous, his crying louder.
The strengthening of a reaction through exercise is a fundamental
fact.
But we should scarcely speak of "learning" if the only modification
consisted in the simple strengthening of native reactions, and at
first thought it is difficult to see how the {298} exercise of any
reaction could modify it in any other respect. But many reflexes are
not perfectly fixed and invariable, but allow of some free play, and
then exercise may fix or stabilize them, as is well illustrated in the
case of the pecking response of the newly hatched chick. If grains are
strewn before a chick one day old, it instinctively strikes at them,
seizes them in its bill and swallows them; but, its aim being poor and
uncertain, it actually gets, at first, only a fifth of the grains
pecked at; by exercise it improves so as to get over half on the next
day, over three-fourths after another day or two, and about 86 percent
(which seems to be its limit) after about ten days of practice.
Exercise has here modified a native reaction in the way of making it
more definite and precise, by strengthening the accurate movement as
against all the variations of the pecking movement that were made at
the start. Where a native response is variable, exercise tends towards
constancy, and so towards the _fixation_ of definite habits.
A reflex may come to be _attached_ to a new stimulus, that does not
naturally arouse it. A child who has accidentally been pricked with a
pin, and of course made the flexion reflex in response to this natural
stimulus, will make this same reaction to the sight of a pin
approaching his skin. The seen pin is a _substitute stimulus_ that
calls out the same response as the pin prick. This type of
modification gives a measure of control over the reflexes; for when we
pull the hand back voluntarily, or wink at will, or breathe deeply at
will, we are executing these movements without the natural stimulus
being present.
Voluntary control includes also the ability to omit a response even if
the natural stimulus is present. Holding the breath, keeping the eyes
wide open in spite of the tendency to wink, not swallowing though the
mouth is full of saliva, holding the hand steady when it is being
pricked, and many {299} similar instances of control over reflexes are
cases of _detachment_ of a native reaction from its natural stimulus.
Not "starting" at a sudden sound to which we have grown used and not
turning the eyes to look at a very familiar object, are other
instances of this detachment.
The _substitute response_ is another modification to be placed
alongside of the substitute stimulus. Here a natural stimulus calls
out a motor response different from its natural response. The muttered
imprecation of the adult takes the place of the child's scream of
pain. The loose holding of the pen between the thumb and the first two
fingers takes the place of the child's full-fisted grasp.
Finally, an important type of modification consists in the
_combination_ of reflex movements into larger coördinations. One hand
grasps an object, while the other hand pulls, pushes or strikes it.
Or, both hands grasp the object but in different ways, as in handling
an ax or shovel. These cases illustrate simultaneous coördination, and
there is also a serial coördination, in which a number of simple
instinctive movements become hitched together in a fixed order.
Examples of this are seen in dancing, writing a word, and, most
notably, in speaking a word or familiar phrase.
In these ways, by strengthening, fixing and combining movements, and
by new attachments and detachments between stimulus and response, the
instinctive motor activity of the baby passes over into the skilled
and habitual movement of the adult.
Acquired Tendencies
In the sphere of _impulse_ and _emotion_ the same kinds of
modification occur. Detachment of an impulse or emotion from its
natural stimulus is very much in evidence, since {300} what frightens
or angers or amuses the little child may have no such power with the
adult. One little boy of two could be thrown into gales of laughter by
letting a spoon drop with a bang to the floor; and you could repeat
this a dozen times in quick succession and get the response every
time. But this stimulus no longer worked when he had advanced to the
age of four.
The emotions get attached to substitute stimuli. Amusement can be
aroused in an older child by situations that were not at all amusing
to the baby. New objects arouse fear, anger, rivalry or curiosity. The
emotions of the adult--with the exception of sex attraction, which is
usually very weak in the child--are the emotions of the child, but
they are aroused by different stimuli.
Not only so, but the emotions express themselves differently in the
child and the adult. Angry behavior is one thing in the child, and
another thing in the adult, so far as concerns external motor action.
The child kicks and screams, where the adult strikes with his fist, or
vituperates, or plots revenge. The internal bodily changes in emotion
are little modified as the individual grows up--except that different
stimuli arouse them--but the overt behavior is greatly modified;
instead of the native reactions we find substitute reactions.
A little girl of three years, while out walking in the woods with her
family, was piqued by some correction from her mother, but, instead of
showing the instinctive signs of temper, she picked up a red autumn
leaf and offered it to her mother, with the words, very sweetly
spoken, "Isn't that a pretty leaf?" "Yes," said her mother,
acquiescently. "Wouldn't you like to have that leaf?" "Yes, indeed."
"I'll throw it away!" (in a savage tone of voice, and with a gesture
throwing the leaf away). Here we have an early form of substitute
reaction, and can glimpse how such {301} reactions become attached to
the emotions. The natural outlet for the child's anger was blocked,
probably because previous outbursts of rage had not had satisfactory
consequences, so that the anger was dammed up, or "bottled up", for
the instant, till the child found some act that would give it vent.
Now supposing that the substitute reaction gave satisfaction to the
child, we can well imagine that it would become attached to the angry
state and be used again in a similar case. Thus, without outgrowing
the emotions, we may outgrow emotional behavior that is socially
unacceptable.
Emotions are also combined, much as reflexes are combined. The same
object which on one occasion arouses in us one emotion may arouse
another emotion on another occasion, so that eventually, whenever we
see that object, we respond by a blend of the two emotions. Your chief
may terrify you on some occasions, at other times amaze you by his
masterly grasp on affairs, and again win your affection by his care
for your own welfare; so that your attitude toward "the boss" comes to
be a blend of fear, admiration and gratitude. Religion and patriotism
furnish good examples of compound emotions.
Well, then, adult behavior compared with the instinctive behavior of
the little child shows these several types of modification. This is
interesting, but it is not all we wish to know. We want to know how
the modification comes about; that is, we want to get an insight into
the process of learning. Scientifically, this is one of the most
fascinating topics in psychology--how we learn, how we are molded or
modified by experience--and practically, it is just as important,
since if we wish to educate, train, mold, improve ourselves or others,
it is the _process_ of modification that we must control; and to
control it we must understand it.
To understand it we must watch the process itself; and {302} therefore
we turn to studies that trace the course of events in human and animal
learning.
Animal Learning
Animals do learn, all the vertebrates, at least, and many of the
invertebrates. They often learn more slowly than men, but this is an
advantage for our present purpose, since it makes the learning process
easier to follow. Mere anecdotes of intelligent behavior in animals
are of little value, but experimental studies, in which the animal's
progress is followed, step by step, from the time when he is
confronted with a perfectly novel situation till he has mastered the
trick, have now been made in great numbers, and a few typical
experiments will serve as a good introduction to the whole subject of
learning.
The negative adaptation experiment.
Apply a harmless and meaningless stimulus time after time; at first
the animal makes some instinctive exploring or defensive reaction; but
with continued repetition of the stimulus, he ceases after a while to
respond. The instinctive reaction has been detached from one of its
natural stimuli.
Even in unicellular animals, negative adaptation can be observed, but
in them is only temporary, like the "sensory adaptation" described in
the chapter on sensation. Stop the stimulus and the original
responsiveness returns after a short time. Nothing has been learned,
for what is learned remains after an interval of rest.
In higher animals, permanent adaptation is common, as illustrated by a
famous experiment on a spider. While the spider was in its web, a
tuning fork was sounded, and the spider made the defensive reaction of
dropping to the ground. It climbed back to its web, the fork was
sounded again, the spider dropped again; but after several {303}
repetitions in quick succession, the spider ceased to respond. Next
day, to be sure, it responded as at first; but after the same
performance had been repeated on several days, it ceased permanently
to respond to this stimulus.
Negative adaptation is common in domestic animals, as well as in men.
The horse "gets used" to the harness, and the dog to the presence of a
cat in the house. Man grows accustomed to his surroundings, and to
numerous unimportant sights and sounds.
The conditioned reflex experiment.
Put into a dog's mouth a tasting substance that arouses the flow of
saliva, and at the same instant ring a bell; and repeat this
combination of stimuli many times. Then ring the bell alone, and the
saliva flows in response to the bell. The bell is a _substitute
stimulus_, which has become attached to the salivary response by dint
of having been often given along with the natural stimulus that
arouses this response. At first thought, this is very weird, but do we
not know of similar facts in every-day experience? The dinner bell
makes the mouth water; the sight of food does the same, even the name
of a savory dish will do the same.
Quite possibly, the learning process by which the substitute stimulus
becomes attached to the salivary reaction is more complex in man's
case. He may _observe_ that the dinner bell means dinner, whereas the
dog, we suppose, does not definitely observe the connection of the
bell and the tasting substance. What the experiment shows is that a
substitute stimulus can become attached to a reaction under very
simple conditions.
A conditioned reflex experiment on a child deserves mention. A young
child, confronted with a rabbit, showed no fear, but on the contrary
reached out his hand to take the rabbit. At this instant a loud
rasping noise was produced just behind the child, who quickly withdrew
his hand with {304} signs of fear. After this had been repeated a few
times, the child shrank from the rabbit and was evidently afraid of
it. Probably it is in this way that many fears, likes and dislikes of
children originate.
The signal experiment.
Place a white rat before two little doors, both just alike except that
one has on it a yellow circle. The rat begins to explore. If he enters
the door with the yellow sign, he finds himself in a passage which
leads to a box of food; if he enters the other door he gets into a
blind alley, which he explores, and then, coming out, continues his
explorations till he reaches the food box and is rewarded. After this
first trial is thus completed, place him back at the starting point,
and he is very apt to go straight to the door that previously led to
the food, for he learns simple locations very quickly. But meanwhile
the experimenter may have shifted the yellow sign to the other door,
connected the passage behind the marked door with the food box, and
closed off the other passage; for the yellow disc in this experiment
always marks the way to the food, and the other door always leads to a
blind alley. The sign is shifted irregularly from one door to the
other. Whenever the rat finds himself in a blind alley, he comes out
and enters the other door, so finally getting his reward on every
trial. But for a long time he seems incapable of responding to the
yellow signal. However, the experimenter is patient; he gives the rat
twenty trials a day, keeping count of the number of correct responses,
and finds the number to increase little by little, till after some
thirty days every response is correct and unhesitating. The rat has
learned the trick.
He learns the trick somewhat more rapidly if punishment for incorrect
responses is added to reward for correct responses. Place wires along
the floor of the two passages, and switch an electric current into the
blind alley, behind {305} the door that has no yellow circle on it.
When the rat enters the blind alley and gets a shock, he makes a
prompt avoiding reaction, scampering back to the starting point and
cowering there for some time; eventually he makes a fresh start,
avoids the door that led to the shock and therefore enters the other
door, though apparently without paying any attention to the yellow
sign, since when, on the next trial, the sign is moved, he avoids the
_place_ where he got the shock, without reference to the sign. But in
a series of trials he learns to follow the sign.
Learning to respond to a signal might be classified under the head of
substitute stimulus, since the rat learns to respond to a stimulus,
the yellow disk, that at first left him unmoved. But more careful
consideration shows this to be, rather, a case of substitute response.
The natural reaction of a rat to a door is to enter it, not to look at
its surface, but the experiment forces him to make the preliminary
response of attending to the appearance of the door before entering
it. The response of attending to the surface of the door is
substituted for the instinctive response of entering. Otherwise put:
the response of finding the marked door and entering that is
substituted for the response of entering any door at random.
The maze experiment.
An animal is placed in an enclosure from which it can reach food by
following a more or less complicated path. The rat is the favorite
subject for this experiment, but it is a very adaptable type of
experiment and can be tried on any animal. Fishes and even crabs have
mastered simple mazes, and in fact to learn the way to a goal is
probably possible for any species that has any power of learning
whatever. The rat, placed in a maze, explores. He sniffs about, goes
back and forth, enters every passage, and actually covers every square
inch of the maze at least once; and in the course of these
explorations {306} hits upon the food box. Replaced at the starting
point, he proceeds as before, though with more speed and less dallying
in the blind alleys. On successive trials he goes less and less deeply
into a blind alley, till finally he passes the entrance to it without
even turning his head. Thus eliminating the blind alleys one after
another, he comes at length to run by a fixed route from start to
finish.
[Illustration: Fig. 47.--(From Hicks.) Ground plan of a maze used in
experiments on the rat. The central square enclosure is the food box.
The dotted line shows the path taken by a rat on Its fourth trial,
which occupied 4 minutes and 2 seconds.]
At first thought, the elimination of useless moves seems to tell the
whole story of the rat's learning process; but careful study of his
behavior reveals another factor. When the rat approaches a turning
point in the maze, his course bends so as to prepare for the turn; he
does not simply advance to the turning point and then make the turn,
but several steps before he reaches that point are organized or
coördinated into a sort of unit.
{307}
[Illustration: Fig. 48.--(From Watson.) Learning curve for the rat
in the maze. This is a composite or average, derived from the
records of four animals. The height of the heavy line above the base
line, for any trial, indicates the number of minutes consumed in
that trial in passing through the maze and reaching the food box.
The gradual descent of the curve indicates the gradual decrease in
time required, and thus pictures the progress of the animals in
learning the maze.]
The combination of steps into larger units is shown also by certain
variations of the experiment. It is known that the rat makes little
use of the sense of sight in learning the maze, guiding himself mostly
by the muscle sense. Now if the maze, after being well learned, is
altered by shortening one of the straight passages, the rat runs full
tilt against the new end of the passage, showing clearly that he was
proceeding, not step by step, but by _runs_ of some length. Another
variation of the experiment is to place a rat that has learned a maze
down in the midst of it, instead of at {308} the usual starting point.
At first he is lost, and begins exploring, but, hitting on a section
of the right path, he gets his cue from the "feel" of it, and races
off at full speed to the food box. Now his cue could not have been any
single step or turn, for these would all be too much alike; his cue
must have been a familiar _sequence_ of movements, and that sequence
functions as a unit in calling out the rest of the habitual movement.
[Illustration: Fig. 49.--(From Watson.) A puzzle box. The animal must
here reach his paw out between the bars and raise the latch, _L_. A
spring then gently opens the door.]
In short, the rat learns the path by _elimination_ of false reactions
and by _combination_ of single steps and turns into larger
reaction-units.
The puzzle-box experiment.
Place a hungry young cat in a strange cage, with a bit of fish lying
just outside, and you are sure to get action. The cat extends his paw
between the slats but cannot reach the fish; he pushes his nose
between the slats but cannot get through; he bites the slats, claws at
anything small, shakes anything loose, and tries every part of the
cage. Coming to the button that fastens {309} the door, he attacks
that also, and sooner or later turns the button, gets out, and eats
the fish. The experimenter, having noted the time occupied in this
first trial, replaces the cat, still hungry, in the cage, and another
bit of fish outside. Same business, but perhaps somewhat quicker
escape. More trials, perhaps on a series of days, give gradually
decreasing times of escape. The useless reactions are gradually
eliminated, till finally the cat, on being placed in the cage, goes
instantly to the door, turns the button, goes out and starts to eat,
requiring but a second or two for the whole complex reaction. Perhaps
15 or 20 trials have been required to reach this stage of prompt,
unerring response. The course of improvement is rather irregular, with
ups and downs, but with no sudden shift from the varied reaction of
the first trial to the fixed reaction of the last. The learning
process has been gradual.
This is the typical instance of learning by "trial and error", which
can be defined as varied reaction with gradual elimination of the
unsuccessful responses and fixation of the successful one. It is also
a case of the substitute response. At first, the cat responds to the
situation by reaching or pushing straight towards the food, but it
learns to substitute for this most instinctive response the less
direct response of going to another part of the cage and turning a
button.
The cat in this experiment is evidently trying to get out of the cage
and reach the food. The situation of being confined in a cage while
hungry arouses an impulse or tendency to get out; but this tendency,
unable at once to reach its goal, is dammed up, and remains as an
inner directive force, facilitating reactions that are in the line of
escape and inhibiting other reactions. When the successful response is
hit upon, and the door opened, the dammed-up energy is discharged into
this response; and, by repetition, {310} the successful response
becomes closely attached to the escape-tendency, so as to occur
promptly whenever the tendency is aroused.
There is no evidence that the cat reasons his way out of the cage. His
behavior is impulsive, not deliberative. There is not even any
evidence that the cat clearly observes how he gets out. If he made a
clean-cut observation of the manner of escape, his time for escaping
should thereupon take a sudden drop, instead of falling off gradually
and irregularly from trial to trial, as it does fall off. Trial and
error learning is learning by doing, and not by reasoning or
observing. The cat learns to get out by getting out, not by seeing how
to get out.
Summary of Animal Learning
Let us take account of stock at this point, before passing to human
learning, and attempt to generalize what we have observed in animals
of the process of learning.
(1) _Elimination_ of a response, which means _detachment_ of a
response from the stimulus that originally aroused it, occurs in three
main cases:
(a) Elimination occurs most quickly when the response brings actual
_pain_; the animal makes the avoiding reaction to the pain and
quickly comes to make this response to the place where the pain
occurred; and thus the positive reaction to this place is
eliminated.
(b) Elimination occurs more gradually when the response, without
resulting in actual pain, brings _failure_ or delay in reaching a
goal towards which the animal is tending. The positive response of
entering and exploring a blind alley grows weaker and weaker, till
the blind alley is neglected altogether.
(c) Elimination of a response also occurs, slowly, through _negative
adaptation_ to a stimulus that is harmless and also useless.
{311}
(2) New _attachments_ or _linkages_ of stimulus and response occur in
two forms, which are called "substitute stimulus" and "substitute
response".
[Footnote: The writer hopes that no confusion will be caused by
his use of several words to express this same meaning.
"Attachment of stimulus and response", "linkage of stimulus and
response", "connection between stimulus and response", and "bond
between stimulus and response", all mean exactly the same; but
sometimes one and sometimes another seems to bring the meaning
more vividly to mind.]
(a) _Substitute stimulus_ refers to the case where the natural
response is not itself modified, but becomes attached to another
stimulus than the one that originally aroused it. This new linkage
can sometimes be established by simply giving the original stimulus
and the substitute stimulus at the same time, and doing so
repeatedly, as in the conditioned reflex experiment.
(b) _Substitute response_ refers to the case where the stimulus
remaining as it originally was, a new reaction is attached to it in
place of the original response. The conditions under which this
takes place are more complex than those that give the substitute
stimulus. A tendency towards some goal must first be aroused, and
then blocked by the failure of the original response to lead to the
goal. The dammed-up tendency then facilitates other responses, and
gives trial and error behavior, till some one of the trial responses
leads to the goal; and this successful response is gradually
substituted for the original response, and becomes firmly attached
to the situation and tendency.
(3) New _combinations of responses_ occur, giving higher motor units.
Human Learning
To compare human and animal learning, and notice in what ways the
human is superior, cannot but throw light on the whole problem of the
process of learning. It is obvious {312} that man learns more quickly
than the animals, that he acquires more numerous reactions, and a much
greater variety of reactions; but the important question is how he
does this, and how his learning process is superior.
We must first notice that all the forms of learning displayed by the
animal are present also in the human being. Negative adaptation is
important in human life, and the conditioned reflex is important, as
has already been suggested. Without negative adaptation, the adult
would be compelled to attend to everything that aroused the child's
curiosity, to shrink from everything that frightened the child, to
laugh at everything that amused the child. The conditioned reflex type
of learning accounts for a host of acquired likes and dislikes. Why
does the adult feel disgust at the mere sight of the garbage pail or
the mere name of cod liver oil? Because these inoffensive visual and
auditory stimuli have been associated, or paired, with odors and
tastes that naturally aroused disgust.
The signal experiment is duplicated thousands of times in the
education of every human being. He learns the meaning of signs and
slight indications; that is, he learns to recognize important facts by
aid of signs that are of themselves unimportant. We shall have much to
say on this matter in a later chapter on perception. Man learns signs
more readily than such an animal as the rat, in part because the human
being is naturally more responsive to visual and auditory stimuli. Yet
the human being often has trouble in learning to read the signs
aright. He assumes that a bright morning means good weather all day,
till, often disappointed, he learns to take account of less obvious
signs of the weather. Corrected for saying, "You and me did it", he
adopts the plan of always saying "you and I", but finds that this
quite unaccountably brings ridicule on him at times, so that gradually
he _may_ come to say the one or the {313} other according to obscure
signs furnished by the structure of the particular sentence. The
process of learning to respond to obscure signs seems to be about as
follows: something goes wrong, the individual is brought to a halt by
the bad results of his action, he then sees some element in the
situation that he had previously overlooked, responds to this element,
gets good results, and so--perhaps after a long series of
trials--comes finally to govern his action by what seemed at first
utterly insignificant.
Trial and error learning, though often spoken of as characteristically
"animal", is common enough in human beings. Man learns by impulsively
doing in some instances, by rational analysis in others. He would be
at a decided disadvantage if he could not learn by trial and error,
since often the thing he has to manage is very difficult of rational
analysis. Much motor skill, as in driving a nail, is acquired by
"doing the best you can", getting into trouble, varying your
procedure, and gradually "getting the hang of the thing", without ever
clearly seeing what are the conditions of success.
Human Compared With Animal Learning
Fairly direct comparisons have been made between human and animal
learning of mazes and puzzles. In the maze, the human subject has an
initial advantage from knowing he is in a maze and has to master it,
while the rat knows no more than that he is in a strange place, to be
explored with caution on the odd chance that it may contain something
eatable, or something dangerous. But, after once reaching the food
box, the rat begins to put on speed in his movements, and within a few
trials is racing through the maze faster than the adult man, though
not so fast as a child. Adults are more circumspect and dignified,
they make less speed, cover less distance, but also make fewer false
moves {314} and finish in less time. That is in the early trials;
adults do not hold their advantage long, since children and even rats
also reach complete mastery of a simple maze in ten or fifteen trials.
The chief point of superiority of adults to human children, and of
these to animals, can be seen in the adjacent table. It is in the
_first trial_ that the superiority of the adults shows most clearly.
They get a better start, and adapt themselves to the situation more
promptly. Their better start is due to (1) better understanding of the
situation at the outset, (2) more plan, (3) less tendency to "go off
on a tangent", i.e., to respond impulsively to every opening, without
considering or looking ahead. The adult has more inhibition, the child
more activity and responsiveness; the adult's inhibition stands him in
good stead at the outset, but the child's activity enables him to
catch up shortly in so simple a problem as this little maze.
AVERAGE NUMBER OF ERRORS MADE, IN EACH TRIAL IN
LEARNING A MAZE, BY RATS, CHILDREN AND ADULT MEN
(From Hicks and Carr)
Trial
No. Rats Children Adults
1 53 35 10
2 45 9 15
3 30 18 5
4 22 11 2
5 11 9 6
6 8 13 4
7 9 6 2
8 4 6 2
9 9 5 1
10 3 5 1
11 4 1 0
12 5 0 1
13 4 1 1
14 4 0 1
15 4 1 1
16 2 0 1
17 1 0 1
The table reads that, on the first trial in the maze, the rats
averaged 53 errors, the children 35 errors, and the adults 10
errors, and so on. An "error" consisted in entering a blind alley or
in turning back on {315} the course. The subjects tested consisted
of 23 rats, five children varying in age from 8 to 18 years, and
four graduate students of psychology. The human maze was much larger
than those used for the rats, but roughly about the same in
complexity. Since rats are known to make little use of their eyes in
learning a maze, the human subjects were blindfolded. The rats were
rewarded by food, the others simply by the satisfaction of success.
The puzzle boxes used in experiments on animal learning are too simple
for human adults, but mechanical puzzles present problems of
sufficient difficulty. The experimenter hands the subject a totally
unfamiliar puzzle, and notes the time required by the subject to take
it apart; and this is repeated in a series of trials till mastery is
complete. In addition to taking the time, the experimenter observes
the subject's way of reacting, and the subject endeavors at the end of
each trial to record what he has himself observed of the course of
events.
The human subject's behavior in his first trial with a puzzle is often
quite of the trial and error sort. He manipulates impulsively; seeing
a possible opening he responds to it, and meeting a check he backs off
and tries something else. Often he tries the same line of attack time
and time again, always failing; and his final success, in the first
trial, is often accidental and mystifying to himself.
On the second trial, he may still be at a loss, and proceed as before;
but usually he has noticed one or two facts that help him. He is most
likely to have noticed _where_ he was in the puzzle when his
accidental success occurred; for it appears that _locations_ are about
the easiest facts to learn for men as well as animals. In the course
of a few trials, also, the human subject notices that some lines of
attack are useless, and therefore eliminates them. After a time he may
"see into" the puzzle more or less clearly, though sometimes he gets a
practical mastery of the handling of the puzzle, while still obliged
to confess that he does not understand it at all.
{316}
Insight, when it does occur, is of great value. Insight into the
general principle of the puzzle leads to a better general plan of
attack, and insight into the detailed difficulties of manipulation
leads to smoother and defter handling. The human "learning curve" (see
Figure 50) often shows a prolonged stretch of no improvement, followed
by an abrupt change to quicker work; and the subject's introspections
show that 76 per cent, or more of these sudden improvements followed
immediately after some fresh insight into the puzzle.
[Illustration: Fig. 50.--(From Ruger.) Curve for human learning of a
mechanical puzzle. Distance above the base line represents the time
occupied in each trial, the successive trials being arranged in order
from left to right. A drop in the curve denotes a decrease in time,
and thus an improvement. At _X_, the subject saw something about the
puzzle that he had not noticed before and studied it out with some
care, so increasing his time for this one trial, but bringing the time
down thereafter to a new and steady level.]
The value of insight appears in another way when the subject, after
mastering one puzzle, is handed another involving the same principle
in a changed form. If he has seen the principle of the first puzzle,
he is likely to carry over this knowledge to the second, and master
this readily; {317} but if he has simply acquired motor skill with the
first puzzle, without any insight into its principle, he may have as
hard a time with the second as if he had never seen the first.
Learning by Observation
"We learn by doing" is a true proverb, in the sense that we acquire a
reaction by making just that reaction. We must make a reaction in
order to get it really in hand, so that the proverb might be
strengthened to read, "To learn, we must do". But we should make it
false if we strengthened it still further and said "We learn _only_ by
doing". For human beings, at least, learn also by observing.
The "insight" just spoken of consists in observing some fact--often
some relationship--and the value of insight in hastening the process
of learning is a proof that we learn by observation as well as by
actual manipulation. To be sure, observation needs to be followed by
manipulation in order to give practical mastery of a thing, but
manipulation without observation means slow learning and often yields
nothing that can be carried over to a different situation.
Learning by observation is typically human. The adult's superiority in
tackling a maze may be summed up by saying that he observes more than
the child--much more than the animal--and governs his behavior by his
observations. The enormous human superiority in learning a simple
puzzle, of the sort used in experiments on animals, arises from seeing
at once the key to the situation.
A chimpanzee--one of the most intelligent of animals--was tested with
a simple puzzle box, to be opened from outside by turning a button
that prevented the door from opening. The device was so simple that
you would expect the animal to see into it at once. A banana was put
into the box and the door fastened with the button. The {318}
chimpanzee quickly found the door, and quickly found the button, which
he proceeded to pull about with one hand while pulling the door with
the other. Without much delay, he had the button turned and the door
open. After about three trials, he had a practical mastery of the
puzzle, showing thus considerable superiority over the cat, who would
more likely have required twelve or fifteen trials to learn the trick.
But now a second button was put on a few inches from the first, both
being just alike and operating in the same way. The chimpanzee paid no
attention to this second button, but turned the first one as before,
and when the door failed to open, kept on turning the first button,
opening it and closing it and always tugging at the door. After a
time, he did shift to the second button, but as he had left the first
one closed, his manipulation of the second was futile. It was a long,
hard job for him to learn to operate both buttons correctly; and the
experiment proved that he did not observe how the button kept the door
from opening, but only that the button was the thing to work with in
opening the door. At one time, indeed, in order to force him to deal
with the second button, the first one was removed, but he still went
to the place where it had been and fingered about there. What he had
observed was chiefly the place to work at in order to open the door.
We must grant that animals observe locations, but most of their
learning is by doing and not by observing.
Here is another experiment designed to test the ability of animals to
learn by observation. The experimenter takes two cats, one having
mastered a certain puzzle box, the other not, and places the untrained
cat where it can watch the trained one do its trick. The trained cat
performs repeatedly for the other's benefit, and is then taken away
and the untrained cat put into the puzzle box. But he has derived no
benefit from what has gone on before his eyes, and must learn by trial
{319} and error, the same as any other cat; he does not even learn any
more quickly than he otherwise would have done.
The same negative results are obtained even with monkeys, but the
chimpanzee shows some signs of learning by observation. One chimpanzee
having learned to extract a banana from a long tube by pushing it out
of the further end with a stick which the experimenter had kindly left
close by, another chimpanzee was placed where he could watch the first
one's performance and did watch it closely. Then the first animal was
taken away and the second given a chance. He promptly took the stick
and got the banana, without, however, imitating the action of the
first animal exactly, but pulling the banana towards him till he could
reach it. This has been called learning by imitation, but might better
be described as learning by observation.
Such behavior, quite rare among animals, is common in human children,
who are very observant of what older people do, and imitate them on
the first opportunity, though often this comes after an interval. The
first time a child speaks a new word is usually not right after he has
heard it. When, on previous occasions, he has heard this word, he has
not attempted to copy it, but now he brings it out of himself. He has
not acquired the word by direct imitation, evidently, but by what has
been called "delayed imitation", which consists in observation at the
time followed later by attempts to do what has been observed.
Observation does not altogether relieve the child of the necessity of
learning by trial and error, for often his first imitations are pretty
poor attempts; but observation gives him a good start and hastens the
learning process considerably. "Learning by imitation", then, is, more
properly, "learning by observation followed by trial and error" and
the reason so little of it appears in animals is their lack of
observation.
_Learning by thinking_ depends on observation, since in {320} thought
we make use of facts previously observed. Seldom, unless in the
chimpanzee and other manlike apes, do we see an animal that appears to
be thinking. The animal is always doing, or waiting, or sleeping. He
seems too impulsive to stop and think. But a man may observe something
in the present problem that calls previous observations to mind, and
by mentally combining observations made at different times may figure
out the solution before beginning motor manipulation. Usually,
however, some manipulation of the trial and error sort is needed
before the thought-out solution will work perfectly.
Sometimes mental rehearsal of a performance assists in learning it, as
we see in the beginner at automobile driving, who, while lying in bed
after his first day's experience, mentally goes through the motions of
starting the engine and then the car, and finds that this "absent
treatment" makes the car easier to manage the next day.
In summing up the points of superiority of human over animal learning,
we may note that--
1. Man is perhaps a quicker learner, anyway, without regard to his
better methods of learning. This, however, is open to doubt, in view
of the very rapid learning by animals of such reactions as the
avoidance of a place where they have been hurt.
2. Man is a better observer, and this is the great secret of his quick
learning. He is especially strong in observing relationships, or
"principles" as we often call them.
3. He has more control over his impulses, and so finds time and energy
for observing and thinking.
4. He is able to work mentally with things that are not present; he
remembers things he has seen, puts together facts observed at
different times, thinks over problems that are not actually
confronting him at the moment, and maps out plans of action.
{321}
The Learning of Complex Practical Performances
A great deal of light has been thrown on the learning process by
psychological studies of the course of improvement in mastering such
trades as telegraphy and typewriting.
A student of telegraphy was tested once a week to see how rapidly he
could send a message, and also how rapidly he could "receive a message
off the wire", by listening to the clicking of the sounder. The number
of letters sent or received per minute was taken as the measure of his
proficiency. This number increased rapidly in the first few weeks, and
then more and more slowly, giving a typical learning curve, or
"practice curve", as it is also called.
[Illustration: Fig. 51.--(From Bryan and Harter.) Practice curve of
student W. J. R. in learning telegraphy. The height of the curve
indicates the number of letters sent or received per minute. Therefore
a rise of the curve here indicates improvement.]
The curve for sending, aside from minor irregularities, rose with a
fairly smooth sweep, tapering off finally towards the "physiological
limit", the limit of what the nerves and muscles of this individual
could perform.
[Footnote: A good example of the physiological limit is seen in the
hundred yard dash, since apparently no one, with the best of
training, can lower the record much below ten seconds; and any given
individual's limit may be considerably worse than this, according to
his build, muscular strength and quickness of nerve centers. The
simple reaction gives another good example; every one has his limit,
beyond which no amount of training will lower his reaction time; the
neuromuscular system simply will not work any faster.]
The receiving {322} curve rose more slowly than the sending curve, and
flattened out after about four months of practice, showing little
further improvement for the next two months. This was a discouraging
time for the student, for it seemed as if he could never come up to
the commercial standard. In fact, many learners drop out at this
stage. But this student persisted, and, after the long period of
little improvement, was gratified to find his curve going up rapidly
again. It went up rapidly for several months, and when it once more
tapered off into a level, he was well above the minimum standard for
regular employment.
Such a flat stretch in a practice curve, followed by a second
rise--such a period of little or no improvement, followed by rapid
improvement--is called a "plateau". Sometimes due to mere
discouragement, or to the inattention that naturally supervenes when
an act becomes easy to perform, it often has a different cause. It
may, in fact, represent a true physiological limit for the act as it
is being performed, and the subsequent rise to a higher level may
result from _improved methods_ of work. That was probably the case
with the telegrapher.
[Footnote: A plateau of this sort is present in the learning curve
for mastery of a puzzle, given on p. 316.]
The telegrapher acquires skill by improving his methods, rather than
by simply speeding up. He acquires methods that he didn't dream of at
first. At the start, he must learn the alphabet of dots and dashes.
This means, for purposes of sending, that he must learn the little
rhythmical pattern of finger movements that stands for each letter;
and, for purposes of receiving, that he must learn the rhythmical
{323} pattern of clicks from the sounder that stands for a letter.
When he has learned the alphabet, he is able to send and receive
slowly. In sending, he spells out the words, writing each letter as a
separate act. In receiving, at this early stage, he must pick out each
separate letter from the continuous series of clicks that he hears
from the sounder. By degrees, the letters become so familiar that he
goes through this spelling process easily; and, doing now so much
better than at the outset, he supposes he has learned the trade, in
its elements, and needs only to put on more speed.
But not at all! He has acquired but a small part of the necessary
stock-in-trade of the telegrapher. He has his "letter habits", but
knows nothing as yet of "word habits". These gradually come to him as
he continues his practice. He comes to know words as units, motor
units for sending purposes, auditory units for receiving. The
rhythmical pattern of the whole word becomes a familiar unit. Short,
much used words are first dealt with as units, then more and more
words, till he has a large vocabulary of word habits. A word that has
become a habit need not be spelled out in sending, nor laboriously dug
out letter by letter in receiving; you simply think the word "train",
and your finger taps it out as a connected unit; or, in receiving, you
recognize the characteristic pattern of this whole series of clicks.
When the telegrapher has reached this word habit stage, he finds the
new method far superior, in both speed and sureness, to the letter
habit method which he formerly assumed to be the whole art of
telegraphy. He does not even stop with word habits, but acquires a
similar control over familiar phrases.
Higher Units and Overlapping
The acquisition of skill in telegraphy consists mostly in learning
these _higher units_ of reactions. It is the same in {324} learning to
typewrite. First you must learn your alphabet of letter-striking
movements; by degrees you reduce these finger movements to firm
habits, and are then in the letter-habit stage, in which you spell out
each word as you write it. After a time, you write a familiar word
without spelling it, by a coördinated series of finger movements; you
write by word units, and later, in part, by phrase units; and these
higher units give you speed and accuracy.
Along with this increase in the size of the reaction-units employed
goes another factor of skill that is really very remarkable. This is
the "overlapping" of different reactions, a species of doing two or
more things at once, only that the two or more reactions are really
parts of the same total activity. The simplest sort of overlap can be
illustrated at an early stage in learning to typewrite. The absolute
beginner at the typewriter, in writing "and", pauses after each letter
to get his bearings before starting on the next; but after a small
amount of practice he will locate the second letter on the keyboard
while his finger is still in the act of striking the first letter.
Thus the sensory part of the reaction to the second letter commences
before the motor part of reacting to the first letter is finished; and
this overlap does away with pauses between letters and makes the
writing smoother and more rapid.
With further practice in typewriting, when word habits and phrase
habits are acquired, overlap goes to much greater lengths. One expert
kept her eyes on the copy about four words ahead of her fingers on the
keyboard, and thus was reacting to about four words at the same time:
one word was just being read from the copy, one word was being
written, and the two words between were being organized and prepared
for actual writing. The human typewriting mechanism, consisting of
eye, optic nerve, parts of the brain and cord, motor nerves and
muscles, works somewhat like one of {325} those elaborate machines
which receive raw material steadily at one end perform a series of
operations upon it, and keep turning out finished product at the other
end.
All this is very remarkable, but the same sort of overlapping and
working with large units can be duplicated in many linguistic
performances that every one makes. In reading aloud, the eyes keep
well ahead of the voice, and seeing, understanding and pronouncing are
all applied simultaneously to different words of the passage read. In
talking, the ideas keep developing and the spoken words tag along
behind.
[Illustration: Fig. 52.--(From Book.) Practice curve of a young man
learning to typewrite. Each point on the "curve" represents a daily
record in number of strokes per minute. With improvement, the curve
rises.]
In telegraphy and typewriting, it is almost inevitable that the
learner should start with the alphabet and proceed to gradually larger
units. But in learning to talk, or to read, the process goes the other
way. The child understands spoken words and phrases before breaking
them up into their elementary vocal sounds; and he can better be
taught to read by beginning with whole words, or even with whole {326}
sentences, than by first learning the alphabet and laboriously
spelling out the words. In short, the learning process often takes its
start with the higher units, and reaches the smaller elements only for
the purpose of more precise control.
Moderate Skill Acquired in the Ordinary Day's Work
Merely repeating a performance many times does not give the high
degree of skill that we see in the expert telegrapher or typist.
Ordinarily, we practise much less assiduously, are much less zealous,
and have no such perfect measure of the success of our work. For
"practice to make perfect", it must be strongly motivated, and it must
be sharply checked up by some index or measure of success or failure.
If the success of a performance can be measured, and chalked up before
the learner's eyes in the form of a practice curve, so that he can see
his progress, this acts as a strong incentive to rapid improvement.
Ordinarily, we have no clear indication of exactly how well we are
doing, and are satisfied if we get through our job easily and without
too much criticism and ridicule from people around. Consequently we
reach only a moderate degree of skill, nowhere near the physiological
limit, and do not acquire the methods of the real expert.
This is very true of the manual worker. Typesetters of ten or more
years' experience were once selected as subjects for an experiment on
the effects of alcohol, because it was assumed that they must have
already reached their maximum skill. In regard to alcohol, the result
was that this drug caused a falling off in speed and accuracy of
work--but that is another story. What we are interested in here is the
fact that, as soon as these long-practised operators found themselves
under observation, and their work measured, they all began to improve
and in the course of a couple of weeks {327} reached quite a new level
of performance. Their former level had been reasonably satisfactory
under workaday conditions, and special incentive was needed to make
them approach their limit.
A similar condition of affairs has been disclosed by "motion studies"
in many kinds of manual work; the movements of the operative have been
photographed or closely examined by the efficiency expert, and
analyzed to determine whether there are any superfluous movements that
could be eliminated, and whether a different method of work would be
economical of time and effort. Usually, superfluous motion has been
found and considerable economy seen to be possible. There is evidently
no law of learning to the effect that continued repetition of a
performance necessarily makes it perfect in speed, ease, or adaptation
to the task in hand. What the manual worker attains as the result of
prolonged experience is a passable performance, but not at all the
maximum of skill.
The brain worker has little to brag of as against the manual worker.
He, too, is only moderately efficient in doing his particular job.
There are brilliant exceptions--bookkeepers who add columns of figures
with great speed and precision, students who know just how to put in
two hours of study on a lesson with the maximum of effect, writers who
always say just what they wish to say and hit the nail on the head
every time--but the great majority of us are only passable. We need
strong incentive, we need a clear and visible measure of success or
failure, we need, if such a thing were possible, a practice curve
before us to indicate where we stand at the present moment with
respect to our past and our possible future.
{328}
Habit
A habit is contrasted with a reflex, in that the reflex is native, the
habit acquired; but both are alike in being prompt and automatic
reactions. The best antithesis to a habit is the response of a person
to a novel situation, where neither nature nor previous experience
gives him a ready response. The new response is exploratory and
tentative, while habit is fixed and definite. The new response is
variable, the habit regular. The new response is slow and uncertain,
the habit fairly quick and accurate. The new response is attended by
effort and strained attention, the habit is easy and often only
half-conscious. The new response is apt to be unsatisfying to the one
who makes it, while habit is comfortable and a source of satisfaction.
To break a habit is most uncomfortable. Nature--at least that "second
nature" which is habit--calls aloud for the customary performance.
Strenuous effort is required to get out of the rut, and the slipping
back into the rut which is almost sure to occur in moments of
inadvertence is humiliating. Result--usually the habit sticks.
But if the habit simply must be broken? Breaking a habit is forming a
counter-habit, and the more positive the counter-habit the better for
us. This counter-habit must not be left to form itself, but must be
practised diligently. Strong motivation is necessary, no half-hearted
acquiescence in somebody else's injunction to get rid of the habit. We
must adopt the counter-habit as ours, and work for a high standard of
skill in it. For example, if we come to realize that we have a bad
habit of grouchiness with our best friends, it is of little use merely
to attempt to deaden this habit; we need to aim at being a positive
addition to the company whenever we are present, and to practise the
art of being good company, checking up our efforts to be sure we are
hitting {329} the right vein, and persisting in our self-training till
we become real artists. It takes some determination for a grouchy
individual to make such a revolution in his conduct; his
self-assertion resists violently, for the grouchiness is part and
parcel of himself and he hates to be anything but himself. He must
conceive a new and inspiring ideal of himself, and start climbing up
the practice curve towards the new ideal.
{330}
EXERCISES
1. Outline the chapter.
2. Which of the acts performed in eating breakfast are instinctive,
which are matters of habit, and which are partly the one and partly
the other?
3. Compare your mental attitude in approaching an unfamiliar and
a familiar task.
4. How does the performance of the expert in swimming or dancing, etc.,
differ from the performance of the beginner? Analyze out the points
of superiority.
5. Show that the element of trial and error is present in (a) the
child's learning to pronounce a word, and (b) learning "how to
take" a person so as to get on well with him.
6. Why is it that our handwriting, though exercised so much, is apt
to grow worse rather than better, while on the contrary our
spelling is apt to improve?
7. How would you rate your efficiency in study? Is it near your
physiological limit, on a plateau, or in a stage of rapid
improvement?
8. A practice experiment. Take several pages of uniform printed
matter, and mark it off into sections of 15 lines. Take your time
for marking every word in one section that contains both e and r.
The two letters need not be adjacent, but must both be present
somewhere In the word. Having recorded your time for this first
section, do the same thing with the next section, and so on for 12
sections. What were you able to observe, introspectively, of your
method of work and changes with practice. From the objective
observations, construct a practice curve.
9. Write brief explanations of the following terms:
practice
habit
higher unit
overlapping
plateau
physiological limit
insight
trial and error
negative adaptation
substitute stimulus
substitute response
conditioned reflex
{331}
REFERENCES
Thorndike's _Animal Intelligence, Experimental Studies,_ 1911, reports
his own pioneer work in this field. See also Chapter X in the same
author's _Educational Psychology, Briefer Course_, 1914.
For other reviews of the work on animal learning, see Watson's
_Behavior_, 1914, pp. 184-250; also Washburn's _Animal Mind_, 2nd
edition, 1917, pp. 257-312.
For human learning and practice, see Thorndike's _Educational
Psychology, Briefer Course_, 1914, Chapters XIV and XV; also Starch's
_Educational Psychology_, 1919, Chapter XI.
For an experiment showing the acquisition of fears by a child, see
Watson and Raynor, "Conditioned Emotional Reactions", in the _Journal
of Experimental Psychology_, 1920, Vol. 3, pp. 1-14.
James's chapter on "Habit", in his _Principles of Psychology_, 1890,
Vol. I, is a classic which every one should read.
{332}
CHAPTER XIV
MEMORY
HOW WE MEMORIZE AND REMEMBER, AND IN WHAT
RESPECTS MEMORY CAN BE MANAGED AND IMPROVED
So much depends on a good memory in all walks of life, and especially
in brain work of any sort, that perhaps it is no wonder that many
students and business and professional men become worried about their
memories and resort to "memory training courses" in the hope of
improvement. The scientific approach to this very practical problem
evidently lies through a careful study of the way in which memory
works, and the general problem may be expressed in the question, how
we learn and remember. This large problem breaks up, on analysis, into
four subordinate questions: how we commit to memory, how we retain
what has been committed to memory, how we get it back when we want it,
and how we know that what we now get back is really what we formerly
committed to memory. In the case of a person's name which we wish to
remember, how do we "fix it in mind", how do we carry it around with
us when we are not thinking of it, how do we call it up when needed,
and what assures us that we have called up the right name? The four
problems may be named those of
(1) Memorizing, or learning,
(2) Retention
(3) Recall
(4) Recognition
{333}
The Process of Memorizing
As memorizing is one sort of learning, what we have found in the
preceding chapter regarding the learning process should throw light on
our present problem. We found animals to learn by doing, and man by
doing and also by observation or observation combined with doing.
Observation is itself a form of doing, a mental reaction as
distinguished from a purely passive or receptive state; so that
learning is always active. Observation we found to be of great
assistance, both by way of hastening the learning process, and by way
of making what is learned more available for future use. Our previous
studies of learning thus lead us to inquire whether committing to
memory may not consist partly in rehearsing what we wish to learn, and
partly in observing it. Learning by rote, or by merely repeating a
performance over and over again, is, indeed, a fact; and observant
study is also a fact.
Let us see how learning is actually done, as indicated by laboratory
experiments. The psychologist experiments a great deal with the
_memorizing of nonsense material_, because the process can be better
observed here, from the beginning, than when sensible material is
learned. Suppose a list of twenty one-place numbers is to be studied
till it can be recited straight through. The learner may go at it
simply by "doing", which means here by reading the list again and
again, in the hope that it will finally stick. This pure rote learning
will perhaps do the job, but it is slow and inefficient. Usually the
learner goes to work in quite a different way. He observes various
facts about the list. He notices what numbers occur at the beginning
and end, and perhaps in other definite positions. He may group the
digits into two-place or three-place numbers, and notice the
characteristics of these. Any familiar combinations that {334} may
occur, such as 1492, he is likely to spy and remember. Lacking these,
he can at least find similar and contrasting number-groups.
For example, the list
5 7 4 0 6 2 7 3 5 1 4 0 9 2 8 6 3 8 0 1,
which at first sight seemed rather bare of anything characteristic,
was analyzed in a way partly indicated by the commas and semicolons,
5, 74, 0; 62, 73; 5140; 9, 286; 380, 1,
and memorized easily. These observed facts transformed the list from a
shapeless mass into something having definite characteristics, and the
observed characteristics stuck in mind and held the rest together.
Lists of nonsense syllables, such as
wok pam zut bip seg ron taz vis lab mer koj yad
are apt to be learned largely by observation of similarities and
contrasts, by reading meanings into the syllables, and by grouping
into pairs and reading rhythmically. Grouping reduces the twelve
syllables to six two-syllabled nonsense words, some of which may
suggest meaningful words or at least have a swing that makes them easy
to remember. Perhaps the first syllable of every pair is accented, and
a pause introduced after each pair; such devices assist memorizing.
The rhythmical and other _groups_ that are found or made by the
learner in memorizing nonsense lists are, in effect, "higher units",
and have much the same value as the higher units of telegraphy or
typewriting. One who learns many lists in the course of a laboratory
experiment develops a {335} regular system of grouping. First he reads
the list through, in groups of two, three or four items, noticing each
group as a whole; later, he notices the items in each group and how
they are related to each other. He also notices the interrelations of
different groups, and the position of each group in the total series.
All this is quite different from a mere droning along through the
items of the list; it is much more active, and much more observant.
Very interesting are the various ways in which the learner attacks a
list of nonsense syllables, numbers, or disconnected words. He goes to
work something like the cat trying to escape from a strange cage. He
proceeds by a sort of trial and error observation; he keeps looking
for something about the list that will help to fix it. He sees
something that promises well for a moment, then gives it up because he
sees something better. He notices positions, i.e., connects items with
their position in the list. He finds syllables that stand out as
peculiar in some way, being "odd", "fuzzy", smooth, agreeable,
disagreeable, or resembling some word, abbreviation or nickname. He
notes resemblances and contrasts between different syllables. He also
finds groups that resemble each other, or that resemble words.
Besides what he actually finds in the list, he imports _meanings_,
more or less far-fetched, into the list. He may make a rhythmical line
of verse out of it; he may make a story out of it. In short, he both
explores the list as it stands and manipulates it into some shape that
promises to be rememberable.
His line of attack differs according to the particular test that is
later to be made of his memory. Suppose he is shown a number of
pictures, with the understanding that later those now shown are to be
mixed with others, and that he must then pick out those now
shown--then he simply examines each picture for something
characteristic. But {336} suppose each picture is given a name, and he
must later tell the name of each--then he seeks for something in the
picture that can be made to suggest its name. Or suppose, once more,
that the pictures are spread out before him in a row, and he is told
that they will later be mixed and he be required to rearrange them in
the same order in which they are now shown--then he seeks for
relationships between the several pictures. His process of memorizing,
always observant, exploratory and manipulatory, differs in detail
according to the memory task that he expects later to perform.
For another example, suppose an experiment is conducted by the method
of "paired associates". The subject is handed a list of pairs of
words, such as
soprano emblem
grassy concise
nothing ginger
faraway kettle
shadow next
mercy scrub
hilltop internal
recite shoestring
narrative thunder
seldom harbor
jury eagle
windy occupy
squirm hobby
balloon multiply
necktie unlikely
supple westbound
obey inch
broken relish
spellbound ferment
desert expect
He must learn to respond with the second word of each pair when the
first word of the pair is given. What he does, in learning this
lesson, is to take each pair of words as a unit, and try to find
something in the pair that shall make it a firm unit. It may be simply
the peculiar sound or look of a pair that he notes, or it may be some
connection {337} of meaning. Perhaps the pair suggests an image or a
little story. After a few readings, he has the pairs so well in hand
that he can score almost one hundred per cent., if tested immediately.
But now suppose the experimenter springs a surprise, by asking the
subject, as far as possible, to recite the pairs in order, or to tell,
after completing one pair, what was the first word of the next pair.
The subject can do very little at this, and protests that the test is
not fair, since he "paid no attention to the order of the pairs, but
concentrated wholly on each pair separately". Had he expected to
recite the whole list of pairs in order, he would have noticed the
relationship of successive pairs, and perhaps woven them into a sort
of continued story.
In memorizing _connected passages_ of prose or poetry, the "facts
observed" are the general sense and drift of the passage, the meanings
of the parts and their places in the general scheme, the grammatical
structure of the sentences and phrases, and the author's choice of
particular words. Memorizing here is the same general sort of
observant procedure as with nonsense material, greatly assisted by the
familiar sequences of words and by the connected meaning of the
passage, so that a connected passage can be learned in a fraction of
the time needed to memorize an equally long list of unrelated words.
No one in his senses would undertake to memorize an intelligible
passage by the pure rote method, for this would be throwing away the
best possible aid in memorizing; but you will find students who fail
to take full advantage of the sense, because, reading along passively,
they are not on the alert for general trends and outlines. For fixing
in mind the sense of a passage, the essential thing is to see the
sense. If the student gets the point with absolute clearness, he has
pretty well committed it to memory.
{338}
Short-circuiting.
The peculiarities of words or syllables in a list or passage that is
being memorized, the relationships observed among the parts, and the
meanings suggested or imported into the material, though very useful
in the early stages of memorizing, tend to drop out of mind as the
material becomes familiar. A pair of syllables, "lub--mer", may have
first been associated by turning them into "love mother", but later
this meaning fades out, and the two syllables seem simply to belong
together in their own right. A pair of words, like "seldom--harbor",
that were first linked together by the intermediary thought of a boat
that seldom came into the harbor, become directly bound together as
mere words. A short-circuiting occurs, indirect attachments giving way
to direct. Even the outline and general purpose of a connected passage
may fade out of mind, when the passage becomes well learned, so that
it may be almost impossible for a schoolboy, who has learned his
little speech by heart, to deliver it with any consciousness of its
real meaning. A familiar act flattens out and tends to become
automatic and mechanical.
Economy in Memorizing
Memorizing is a form of mental work that is susceptible of management,
and several principles of scientific management have been worked out
that may greatly assist in the learning of a long and difficult
lesson. The problem has been approached from the angle of economy or
efficiency. Suppose a certain amount of time is allowed for the study
of a lesson, how can this time be best utilized?
The first principle of economy has already been sufficiently
emphasized: observant study, directed towards the finding of
relationships and significant facts, is much more efficient than mere
dull repetition.
{339}
The value of recitation in memorizing.
"Recitation" here means reciting to oneself. After the learner has
read his lesson once or twice, he may, instead of continuing simply to
read it, attempt to recite it, prompting himself without much delay
when he is stuck, and verifying his recitation by reference to the
paper. The question is whether this active reciting method of study is
or is not economical of time in memorizing, and whether or not it
fixes the lesson durably in memory. The matter has been thoroughly
tested, and the answer is unequivocally in favor of recitation. The
only outstanding question is as to how soon to start attempting to
recite, and probably no single answer can be given to this question,
so much depends on the kind of material studied, and on peculiarities
of the individual learner. Where the sense rather than the exact
wording of a lesson has to be learned, it is probably best to recite,
in outline, after the first reading, and to utilize the next reading
for filling in the outline.
The results of one series of experiments on this matter are summarized
in the adjoining table.
THE VALUE OF RECITATION IN MEMORIZING (from Gates)
Material studied 16 nonsense syllables 5 short biographies,
totalling about 170 words
Per cent, remembered Per cent. remembered
immediately after 4 hours immediately after 4 hours
All time devoted
to reading 35 15 35 16
1/5 of time devoted
to recitation 50 26 37 19
2/5 of time devoted
to recitation 54 28 41 25
3/5 of time devoted
to recitation 57 37 42 26
4/5 of time devoted
to recitation 74 48 42 26
The time devoted to study was in all cases 9 minutes, and this time
was divided between reading and recitation in different proportions
as stated in the first column at the left. Reading down the next
column, {340} we find that when nonsense syllables were studied and
the test was conducted immediately after the close of the study
period, 35 per cent. were remembered when all the study time had
been devoted to reading, 50 per cent, when the last 1/5 of the study
time had been devoted to recitation, 54 per cent when the last 2/5
of the time had been devoted to recitation; and so on. The next
column shows the per cents. remembered four hours after the study
period. Each subject in these experiments had before him a sheet of
paper containing the lesson to be studied, and he simply read it
till the experimenter gave a signal to recite, after which the
subject recited the lesson to himself as well as he could, prompting
himself from the paper as often as necessary, and proceeded, thus
till the end of the study period. The subjects in these particular
experiments were eighth grade children; adult subjects gave the same
general results.
Three facts stand out from the table: (1) Reading down the columns, we
see that recitation was always an advantage. (2) The advantage was
more marked in the test conducted four hours after study than in the
test immediately following the study. To be sure, there is always a
falling off from the immediate to the later test; there is bound to be
some forgetting when the lesson has been studied for so short a time
as here; but the forgetting proceeds more slowly after recitation than
after all reading. Recitation fixes the matter more durably. (3) The
advantage of recitation is less marked in the meaningful material than
in case of nonsense syllables, though it is marked in both cases. The
reason is that meaningful material can better be read observantly,
time after time, than is possible with nonsense material. Continued
reading of nonsense material degenerates into a mere droning, while in
repeatedly reading meaningful material the learner who is keenly
interested in mastering the passage is sure to keep his mind ahead of
his eyes to some extent, so that his reading becomes half recitation,
after all.
Whence comes the advantage of recitation? It has a twofold advantage:
it is more stimulating, and it is more satisfying. When you know you
are going to attempt recitation at once, you are stimulated to observe
positions, peculiarities, relationships, and meanings, and thus your
study {341} goes on at a higher level than when the test of your
knowledge is still far away, with many readings still to come. You are
also stimulated to manipulate the material, by way of grouping and
rhythm.
On the side of satisfaction, recitation shows you what parts of the
lesson you have mastered and gives you the glow of increasing success.
It shows you exactly where you are failing and so stimulates to extra
attention to those parts of the lesson. It taps the instincts of
exploration, manipulation, and mastery much more effectively than
continued re-reading of the same lesson can do. The latter becomes
very uninteresting, monotonous and fatiguing.
Perhaps, after all, the greatest advantage of reciting is that it
makes you do, in learning, the very act that you have later to perform
in the test; for what you have finally to do is to recite the lesson
without the book. When reading, you are doing something different; and
if it were altogether different, it probably would not help you at all
towards success in the test. But since intelligent reading consists
partly in anticipating and outlining as you go, it is a sort of half
recitation, it is halfway doing what you are trying to learn to do.
Memorizing consists in performing an act, now, with assistance, that
you later wish to perform without assistance; and recitation first
stimulates you to fashion the act conformably to the object in view,
and then exercises you in performing that act.
Spaced and unspaced repetition.