ANIMAL INTELLIGENCE; AN EXPERIMENTAL STUDY OF THE ASSOCIATIVE PROCESSES
IN ANIMALS[4]
This monograph is an attempt at an explanation of the nature of the
process of association in the animal mind. Inasmuch as there have been no
extended researches of a character similar to the present one either in
subject-matter or experimental method, it is necessary to explain briefly
its standpoint.
Our knowledge of the mental life of animals equals in the main our
knowledge of their sense-powers, of their instincts or reactions
performed without experience, and of their reactions which are built up
by experience. Confining our attention to the latter, we find it the
opinion of the better observers and analysts that these reactions can
all be explained by the ordinary associative processes without aid from
abstract, conceptual, inferential thinking. These associative processes
then, as present in animals’ minds and as displayed in their acts, are
my subject-matter. Any one familiar in even a general way with the
literature of comparative psychology will recall that this part of the
field has received faulty and unsuccessful treatment. The careful, minute
and solid knowledge of the sense-organs of animals finds no counterpart
in the realm of associations and habits. We do not know how delicate
or how complex or how permanent are the possible associations of any
given group of animals. And although one would be rash who said that our
present equipment of facts about instincts was sufficient or that our
theories about it were surely sound, yet our notion of what occurs when a
chick grabs a worm are luminous and infallible compared to our notion of
what happens when a kitten runs into the house at the familiar call. The
reason that they have satisfied us as well as they have is just that they
are so vague. We say that the kitten associates the sound ‘kitty kitty’
with the experience of nice milk to drink, which does very well for a
common-sense answer. It also suffices as a rebuke to those who would
have the kitten ratiocinate about the matter, but it fails to tell what
real mental content is present. Does the kitten feel “_sound of call,
memory-image of milk in a saucer in the kitchen, thought of running into
the house, a feeling, finally, of ‘I will run in’_”? Does he perhaps feel
only the sound of the bell and an impulse to run in, similar in quality
to the impulses which make a tennis player run to and fro when playing?
The word ‘association’ may cover a multitude of essentially different
processes, and when a writer attributes anything that an animal may do
to association, his statement has only the negative value of eliminating
reasoning on the one hand and instinct on the other. His position is like
that of a zoölogist who should to-day class an animal among the ‘worms.’
To give to the word a positive value and several definite possibilities
of meaning is one aim of this investigation.
The importance to comparative psychology in general of a more scientific
account of the association-process in animals is evident. Apart from the
desirability of knowing all the facts we can, of whatever sort, there
is the especial consideration that these associations and consequent
habits have an immediate import for biological science. In the higher
animals the bodily life and preservative acts are largely directed by
these associations. They, and not instinct, make the animal use the
best feeding grounds, sleep in the same lair, avoid new dangers and
profit by new changes in nature. Their higher development in mammals
is a chief factor in the supremacy of that group. This, however, is a
minor consideration. The main purpose of the study of the animal mind
is to learn the development of mental life down through the phylum,
to trace in particular the origin of human faculty. In relation to
this chief purpose of comparative psychology the associative processes
assume a rôle predominant over that of sense-powers or instinct, for in
a study of the associative processes lies the solution of the problem.
Sense-powers and instincts have changed by addition and supersedence,
but the cognitive side of consciousness has changed not only in quantity
but also in quality. Somehow out of these associative processes have
arisen human consciousnesses with their sciences and arts and religions.
The association of ideas proper, imagination, memory, abstraction,
generalization, judgment, inference, have here their source. And in the
metamorphosis the instincts, impulses, emotions and sense-impressions
have been transformed out of their old natures. For the origin and
development of human faculty we must look to these processes of
association in lower animals. Not only then does this department need
treatment more, but promises to repay the worker better.
Although no work done in this field is enough like the present
investigation to require an account of its results, the _method_
hitherto in use invites comparison by its contrast and, as I believe,
by its faults. In the first place, most of the books do not give us a
psychology, but rather a _eulogy_, of animals. They have all been about
animal _intelligence_, never about animal _stupidity_. Though a writer
derides the notion that animals have reason, he hastens to add that
they have marvelous capacity of forming associations, and is likely to
refer to the fact that human beings only rarely reason anything out,
that their trains of ideas are ruled mostly by association, as if, in
this latter, animals were on a par with them. The history of books on
animals’ minds thus furnishes an illustration of the well-nigh universal
tendency in human nature to find the marvelous wherever it can. We wonder
that the stars are so big and so far apart, that the microbes are so
small and so thick together, and for much the same reason wonder at the
things animals do. They used to be wonderful because of the mysterious,
God-given faculty of instinct, which could almost remove mountains. More
lately they have been wondered at because of their marvelous mental
powers in profiting by experience. Now imagine an astronomer tremendously
eager to prove the stars as big as possible, or a bacteriologist whose
great scientific desire is to demonstrate the microbes to be very, very
little! Yet there has been a similar eagerness on the part of many
recent writers on animal psychology to praise the abilities of animals.
It cannot help leading to partiality in deductions from facts and more
especially in the choice of facts for investigation. How can scientists
who write like lawyers, defending animals against the charge of having no
power of rationality, be at the same time impartial judges on the bench?
Unfortunately the real work in this field has been done in this spirit.
The level-headed thinkers who might have won valuable results have
contented themselves with arguing against the theories of the eulogists.
They have not made investigations of their own.
In the second place, the facts have generally been derived from
anecdotes. Now quite apart from such pedantry as insists that a man’s
word about a scientific fact is worthless unless he is a trained
scientist, there are really in this field special objections to the
acceptance of the testimony about animals’ intelligent acts which
one gets from anecdotes. Such testimony is by no means on a par with
testimony about the size of a fish or the migration of birds, etc. For
here one has to deal not merely with ignorant or inaccurate testimony,
but also with prejudiced testimony. Human folk are as a matter of fact
eager to find intelligence in animals. They like to. And when the animal
observed is a pet belonging to them or their friends, or when the story
is one that has been told as a story to entertain, further complications
are introduced. Nor is this all. Besides commonly misstating what
facts they report, they report only such facts as show the animal at
his best. Dogs get lost hundreds of times and no one ever notices it
or sends an account of it to a scientific magazine. But let one find
his way from Brooklyn to Yonkers and the fact immediately becomes a
circulating anecdote. Thousands of cats on thousands of occasions sit
helplessly yowling, and no one takes thought of it or writes to his
friend, the professor; but let one cat claw at the knob of a door
supposedly as a signal to be let out, and straightway this cat becomes
the representative of the cat-mind in all the books. The unconscious
distortion of the facts is almost harmless compared to the unconscious
neglect of an animal’s mental life until it verges on the unusual and
marvelous. It is as if some denizen of a planet where communication
was by thought-transference, who was surveying humankind and reporting
their psychology, should be oblivious to all our intercommunication
save such as the psychical-research society has noted. If he should
further misinterpret the cases of mere coincidence of thoughts as facts
comparable to telepathic communication, he would not be more wrong than
some of the animal psychologists. In short, the anecdotes give really the
_abnormal_ or _supernormal_ psychology of animals.
Further, it must be confessed that these vices have been only
ameliorated, not obliterated, when the observation is first-hand, is
made by the psychologist himself. For as men of the utmost scientific
skill have failed to prove good observers in the field of spiritualistic
phenomena,[5] so biologists and psychologists before the pet terrier or
hunted fox often become like Samson shorn. They, too, have looked for the
intelligent and unusual and neglected the stupid and normal.
Finally, in all cases, whether of direct observation or report by good
observers or bad, there have been three other defects. Only a single
case is studied, and so the results are not necessarily true of the
type; the observation is not repeated, nor are the conditions perfectly
regulated; the previous history of the animal in question is not known.
Such observations may tell us, if the observer is perfectly reliable,
that a certain thing takes place; but they cannot assure us that it will
take place universally among the animals of that species, or universally
with the same animal. Nor can the influence of previous experience be
estimated. All this refers to means of getting knowledge about what
animals _do_. The next question is, “What do they _feel_?” Previous work
has not furnished an answer or the material for an answer to this more
important question. Nothing but carefully designed, crucial experiments
can. In abandoning the old method one ought to seek above all to replace
it by one which will not only tell more accurately _what they do_, and
give the much-needed information _how they do it_, but also inform us
_what they feel_ while they act.
To remedy these defects, experiment must be substituted for observation
and the collection of anecdotes. Thus you immediately get rid of several
of them. You can repeat the conditions at will, so as to see whether
or not the animal’s behavior is due to mere coincidence. A number of
animals can be subjected to the same test, so as to attain typical
results. The animal may be put in situations where its conduct is
especially instructive. After considerable preliminary observation of
animals’ behavior under various conditions, I chose for my general method
one which, simple as it is, possesses several other marked advantages
besides those which accompany experiment of any sort. It was merely to
put animals when hungry in inclosures from which they could escape by
some simple act, such as pulling at a loop of cord, pressing a lever,
or stepping on a platform. (A detailed description of these boxes and
pens will be given later.) The animal was put in the inclosure, food was
left outside in sight, and his actions observed. Besides recording his
general behavior, special notice was taken of how he succeeded in doing
the necessary act (in case he did succeed), and a record was kept of the
time that he was in the box before performing the successful pull, or
clawing, or bite. This was repeated until the animal had formed a perfect
association between the sense-impression of the interior of that box and
the impulse leading to the successful movement. When the association
was thus perfect, the time taken to escape was, of course, practically
constant and very short.
If, on the other hand, after a certain time the animal did not succeed,
he was taken out, but _not fed_. If, after a sufficient number of
trials, he failed to get out, the case was recorded as one of complete
failure. Enough different sorts of methods of escape were tried to
make it fairly sure that association in general, not association of a
particular sort of impulse, was being studied. Enough animals were taken
with each box or pen to make it sure that the results were not due to
individual peculiarities. None of the animals used had any previous
acquaintance with any of the mechanical contrivances by which the doors
were opened. So far as possible the animals were kept in a uniform state
of hunger, which was practically utter hunger.[6] That is, no cat or dog
was experimented on, when the experiment involved any important question
of fact or theory, unless I was sure that his motive was of the standard
strength. With chicks this is not practicable, on account of their
delicacy. But with them dislike of loneliness acts as a uniform motive to
get back to the other chicks. Cats (or rather kittens), dogs and chicks
were the subjects of the experiments. All were apparently in excellent
health, save an occasional chick.
By this method of experimentation the animals are put in situations which
call into activity their mental functions and permit them to be carefully
observed. One may, by following it, observe personally more intelligent
acts than are included in any anecdotal collection. And this actual
vision of animals in the act of using their minds is far more fruitful
than any amount of history of what animals have done without the history
of how they did it. But besides affording this opportunity for purposeful
and systematic observation, our method is valuable because it frees the
animal from any influence of the observer. The animal’s behavior is
quite independent of any factors save its own hunger, the mechanism of
the box it is in, the food outside, and such general matters as fatigue,
indisposition, etc. Therefore the work done by one investigator may be
repeated and verified or modified by another. No personal factor is
present save in the observation and interpretation. Again, our method
gives some very important results which are quite uninfluenced by
_any_ personal factor in any way. The curves showing the progress of
the formation of associations, which are obtained from the records of
the times taken by the animal in successive trials, are facts which
may be obtained by any observer who can tell time. They are absolute,
and whatever can be deduced from them is sure. So also the question of
whether an animal does or does not form a certain association requires
for an answer no higher qualification in the observer than a pair of
eyes. The literature of animal psychology shows so uniformly and often so
sadly the influence of the personal equation that any method which can
partially eliminate it deserves a trial.
Furthermore, although the associations formed are such as could not
have been previously experienced or provided for by heredity, they are
still not too remote from the animal’s ordinary course of life. They
mean simply the connection of a certain act with a certain situation
and resultant pleasure, and this general type of association is found
throughout the animal’s life normally. The muscular movements required
are all such as might often be required of the animal. And yet it will
be noted that the acts required are nearly enough like the acts of the
anecdotes to enable one to compare the results of experiment by this
method with the work of the anecdote school. Finally, it may be noticed
that the method lends itself readily to experiments on imitation.
We may now start in with the description of the apparatus and of the
behavior of the animals.[7]
DESCRIPTION OF APPARATUS
[Illustration: FIG. 1.]
The shape and general apparatus of the boxes which were used for the cats
is shown by the accompanying drawing of box K. Unless special figures
are given, it should be understood that each box is approximately 20
inches long, by 15 broad, by 12 high. Except where mention is made to
the contrary, the door was pulled open by a weight attached to a string
which ran over a pulley and was fastened to the door, just as soon as
the animal loosened the bolt or bar which held it. Especial care was
taken not to have the widest openings between the bars at all near the
lever, or wire loop, or what not, which governed the bolt on the door.
For the animal instinctively attacks the large openings first, and if
the mechanism which governs the opening of the door is situated near one
of them, the animal’s task is rendered easier. You do not then get the
association-process so free from the helping hand of instinct as you do
if you make the box without reference to the position of the mechanism to
be set up within it. These various mechanisms are so simple that a verbal
description will suffice in most cases. The facts which the reader should
note are the nature of the movement which the cat had to make, the nature
of the object at which the movement was directed, and the position of the
object in the box. In some special cases attention will also be called
to the force required. In general, however, that was very slight (20 to
100 grams if applied directly). The various boxes will be designated by
capital letters.
A. A string attached to the bolt which held the door ran up over a pulley
on the front edge of the box, and was tied to a wire loop (2½ inches
in diameter) hanging 6 inches above the floor in front center of box.
Clawing or biting it, or rubbing against it even, if in a certain way,
opened the door. We may call this box A ‘_O at front_.’
B. A string attached to the bolt ran up over a pulley on the front edge
of the door, then across the box to another pulley screwed into the
inside of the back of the box 1¼ inches below the top, and passing over
it ended in a wire loop (3 inches in diameter) 6 inches above the floor
in back center of box. Force applied to the loop or _to the string_ as it
ran across the top of the box between two bars would open the door. We
may call B ‘_O at back_.’
B1. In B1 the string ran outside the box, coming down through a hole at
the back, and was therefore inaccessible and invisible from within. Only
by pulling the loop could the door be opened. B1 may be called ‘_O at
back 2d_.’
C. A door of the usual position and size (as in Fig. 1) was kept closed
by a wooden button 3½ inches long, ⅞ inch wide, ½ inch thick. This turned
on a nail driven into the box ½ inch above the middle of the top edge of
the door. The door would fall inward as soon as the button was turned
from its vertical to a horizontal position. A pull of 125 grams would
do this if applied sideways at the lowest point of the button 2¼ inches
below its pivot. The cats usually clawed the button round by downward
pressure on its top edge, which was 1¼ inches above the nail. Then, of
course, more force was necessary. C may be called ‘_Button_.’
D. The door was in the extreme right of the front. A string fastened to
the bolt which held it ran up over a pulley on the top edge and back to
the top edge of the back side of the box (3 inches in from the right
side) and was there firmly fastened. The top of the box was of wire
screening and arched over the string ¾ inch above it along its entire
length. A slight pull on the string anywhere opened the door. This box
was 20 × 16, but a space 7 × 16 was partitioned off at the left by a wire
screen. D may be called ‘_String_.’
D1 was the same box as B, but had the string fastened firmly at the back
instead of running over a pulley and ending in a wire loop. We may call
it ‘_String 2d_.’
E. A string ran from the bolt holding the door up over a pulley and down
to the floor outside the box, where it was fastened 2 inches in front of
the box and 1½ inches to the left of the door (looking from the inside).
By poking a paw out between the bars and pulling this string inward the
door would be opened. We may call E ‘_String outside_.’
In F the string was not fastened to the floor but ended in a loop 2½
inches in diameter which could be clawed down so as to open the door.
Unless the pull was in just the right direction, the string was likely
to catch on the pulley. This loop hung 3 inches above the floor, and 1¾
inches in front of the box. We may call F ‘_String outside unfastened_.’
G was a box 29 × 20½ × 22½, with a door 29 × 12 hinged on the left side
of the box (looking from within), and kept closed by an ordinary thumb
latch placed 15 inches from the floor. The remainder of the front of the
box was closed in by wooden bars. The door was a wooden frame covered
with screening. It was _not_ arranged so as to open as soon as the latch
was lifted, but required a force of 400 grams, even when applied to the
best advantage. The bar of the thumb latch, moreover, would fall back
into place again unless the door were pushed out at least a little. The
top of this box was not of bars or screening, but solid. We may call G
‘_Thumb latch_.’
H was, except for the opening where the door was situated, a perfectly
solid and dark box. In the front was cut an opening about 9 × 7 inches.
A wooden frame covered with wire netting hung in front of this. It was
fastened to the box only by a screw through the middle of the frame’s
top piece, and could therefore be pushed to either side so as to permit
escape from the box if it were prevented from swinging back into place.
I was a box 12 × 14 × 23. The door was 8 inches wide, 4 high, and hinged
at the left side. It was held closed by a wooden bar which moved easily
on a pivot and which could be pushed up by another bar which projected
5 inches into the box. This second bar was pivoted so that downward
pressure on it pushed the first bar up and let the door swing open. The
second bar entered the box at a point 4 inches above the floor and 2½
inches in from the right side of the box. In its normal position its
inner end was 5½ inches above the floor. A depression of 2 inches at that
end was necessary to open the door. Of course, nearer the pivot a shorter
depression would do. The front of the box was closed by bars, but the
rest by solid boards. We may call I ‘_Lever_.’
J was the same as B except that the door was not opened by a weight as
soon as the bolt was pulled up. On the contrary, the door was held closed
by a small piece of board (4 × 3½ × ¾ thick) placed against it outside.
After pulling the loop at the back the cat had to knock down this support
and push the door open. We may call J ‘_Double_.’
K was a box arranged so that three separate acts were required to open
the door, which was held by two bolts at the top and two bars outside.
One of the bolts was connected with a platform in the back center of the
box so that depressing the platform raised the bolt. The other was raised
by a string which ran up over a pulley in the front, across the box 1
inch above the bars, over a pulley near the corner of the box, and down
to the floor, where it was fastened. Pulling on this string, either by
clawing at it where it was running vertically from the last pulley to the
floor, or by putting the paw out between the bars which covered the top
of the box, and clawing the string downward, would raise the bolt. If
both bolts were raised and _either_ bar was pushed up or down far enough
to be out of the way, the cat could escape. K, or ‘_Triple_,’ as it may
be called, is the box reproduced in Figure 1.
L was a box that also required three acts to open the door. It was a
combination of A (O at front), D (string), I (lever). The lever or bar
to be depressed was 2 inches to the right of the door, which was in the
front center. The string to be clawed or bitten ran from front center to
back center 1 inch below the top of the box.
Z was a box with back and sides entirely closed, with front and top
closed by bars and screening, with a small opening in the left-hand
corner. A box was held in front of this and drawn away when the cats
happened to lick themselves. Thus escape and food followed always upon
the impulse to lick themselves, and they soon would immediately start
doing so as soon as pushed into the box. The same box was used with the
impulse changed to that for scratching themselves. The size of this box
was 15 × 10 × 16.
EXPERIMENTS WITH CATS
In these various boxes were put cats from among the following. I give
approximately their ages while under experiment.
No. 1. 8-10 months.
No. 2. 5-7 months.
No. 3. 5-11 months.
No. 4. 5-8 months.
No. 5. 5-7 months.
No. 6. 3-5 months.
No. 7. 3-5 months.
No. 8. 6-6½ months.
No. 10. 4-8 months.
No. 11. 7-8 months.
No. 12. 4-6 months.
No. 13. 18-19 months.
The behavior of all but 11 and 13 was practically the same. When put into
the box the cat would show evident signs of discomfort and of an impulse
to escape from confinement. It tries to squeeze through any opening; it
claws and bites at the bars or wire; it thrusts its paws out through any
opening and claws at everything it reaches; it continues its efforts
when it strikes anything loose and shaky; it may claw at things within
the box. It does not pay very much attention to the food outside, but
seems simply to strive instinctively to escape from confinement. The
vigor with which it struggles is extraordinary. For eight or ten minutes
it will claw and bite and squeeze incessantly. With 13, an old cat, and
11, an uncommonly sluggish cat, the behavior was different. They did not
struggle vigorously or continually. On some occasions they did not even
struggle at all. It was therefore necessary to let them out of some box
a few times, feeding them each time. After they thus associate climbing
out of the box with getting food, they will try to get out whenever put
in. They do not, even then, struggle so vigorously or get so excited
as the rest. In either case, whether the impulse to struggle be due
to an instinctive reaction to confinement or to an association, it is
likely to succeed in letting the cat out of the box. The cat that is
clawing all over the box in her impulsive struggle will probably claw
the string or loop or button so as to open the door. And gradually all
the other non-successful impulses will be stamped out and the particular
impulse leading to the successful act will be stamped in by the resulting
pleasure, until, after many trials, the cat will, when put in the box,
immediately claw the button or loop in a definite way.
The starting point for the formation of any association in these cases,
then, is the set of instinctive activities which are aroused when a cat
feels discomfort in the box either because of confinement or a desire
for food. This discomfort, plus the sense-impression of a surrounding,
confining wall, expresses itself, prior to any experience, in squeezings,
clawings, bitings, etc. From among these movements one is selected by
success. But this is the starting point only in the case of the first
box experienced. After that the cat has associated with the feeling of
confinement certain impulses which have led to success more than others
and are thereby strengthened. A cat that has learned to escape from A by
clawing has, when put into C or G, a greater tendency to claw at things
than it instinctively had at the start, and a less tendency to squeeze
through holes. A very pleasant form of this decrease in instinctive
impulses was noticed in the gradual cessation of howling and mewing.
However, the useless instinctive impulses die out slowly, and often play
an important part even after the cat has had experience with six or eight
boxes. And what is important in our previous statement, namely, that
the activity of an animal when first put into a new box is not directed
by any appreciation of _that_ box’s character, but by certain general
impulses to act, is not affected by this modification. Most of this
activity is determined by heredity; some of it, by previous experience.
My use of the words _instinctive_ and _impulse_ may cause some
misunderstanding unless explained here. Let us, throughout this
book, understand by instinct any reaction which an animal makes to a
situation _without experience_. It thus includes unconscious as well as
conscious acts. Any reaction, then, to totally new phenomena, when first
experienced, will be called instinctive. Any impulse then felt will be
called an instinctive impulse. Instincts include whatever the nervous
system of an animal, as far as inherited, is capable of. My use of the
word will, I hope, everywhere make clear what fact I mean. If the reader
gets the fact meant in mind it does not in the least matter whether he
would himself call such a fact instinct or not. Any one who objects to
the word may substitute ‘hocus-pocus’ for it wherever it occurs. The
definition here made will not be used to prove or disprove any theory,
but simply as a signal for the reader to imagine a certain sort of fact.
The word _impulse_ is used against the writer’s will, but there is no
better. Its meaning will probably become clear as the reader finds it in
actual use, but to avoid misconception at any time I will state now that
_impulse_ means the consciousness accompanying a muscular innervation
_apart from that feeling of the act which comes from seeing oneself
move, from feeling one’s body in a different position, etc._ It is the
_direct feeling of the doing_ as distinguished from the _idea of the
act done_ gained through eye, etc. For this reason I say ‘impulse _and_
act’ instead of simply ‘act.’ Above all, it must be borne in mind that
by impulse I never mean the _motive_ to the act. In popular speech you
may say that hunger is the impulse which makes the cat claw. That will
never be the use here. The word _motive_ will always denote that sort
of consciousness. Any one who thinks that the act ought not to be thus
subdivided into impulse and deed may feel free to use the word _act_ for
_impulse_ or _impulse and act_ throughout, if he will remember that the
act in this aspect of being felt as to be done or as doing is in animals
the important thing, is the thing which gets associated, while the act as
done, as viewed from outside, is a secondary affair. I prefer to have a
separate word, _impulse_, for the former, and keep the word _act_ for the
latter, which it commonly means.
Starting, then, with its store of instinctive impulses, the cat hits
upon the successful movement, and gradually associates it with the
sense-impression of the interior of the box until the connection is
perfect, so that it performs the act as soon as confronted with the
sense-impression. The formation of each association may be represented
graphically by a time-curve. In these curves lengths of one millimeter
along the abscissa represent successive experiences in the box, and
heights of one millimeter above it each represent ten seconds of time.
The curve is formed by joining the tops of perpendiculars erected along
the abscissa 1 mm. apart (the first perpendicular coinciding with the
_y_ line), each perpendicular representing the time the cat was in the
box before escaping. Thus, in Fig. 2 on page 39 the curve marked _12 in
A_ shows that, in 24 experiences or trials in box A, cat 12 took the
following times to perform the act, 160 sec., 30 sec., 90 sec., 60, 15,
28, 20, 30, 22, 11, 15, 20, 12, 10, 14, 10, 8, 8, 5, 10, 8, 6, 6, 7.
A short vertical line below the abscissa denotes that an interval of
approximately 24 hours elapsed before the next trial. Where the interval
was longer it is designated by a figure 2 for two days, 3 for three days,
etc. If the interval was shorter, the number of hours is specified by
1 hr., 2 hrs., etc. In many cases the animal failed in some trial to
perform the act in ten or fifteen minutes and was then taken out by me.
Such failures are denoted by a break in the curve either at its start or
along its course. In some cases there are short curves after the main
ones. These, as shown by the figures beneath, represent the animal’s
mastery of the association after a very long interval of time, and may be
called memory-curves. A discussion of them will come in the last part of
the chapter.
[Illustration: FIG. 2.]
The time-curve is obviously a fair representation of the progress of
the formation of the association, for the two essential factors in the
latter are the disappearance of all activity save the particular sort
which brings success with it, and perfection of that particular sort of
act so that it is done precisely and at will. Of these the second is, on
deeper analysis, found to be a part of the first; any clawing at a loop
except the particular claw which depresses it is theoretically a useless
activity. If we stick to the looser phraseology, however, no harm will
be done. The combination of these two factors is inversely proportional
to the time taken, provided the animal surely wants to get out at once.
This was rendered almost certain by the degree of hunger. Theoretically
a perfect association is formed when both factors are perfect,—when the
animal, for example, does nothing but claw at the loop, and claws at it
in the most useful way for the purpose. In some cases (_e.g._ 2 in K on
page 53) neither factor ever gets perfected in a great many trials. In
some cases the first factor does but the second does not, and the cat
goes at the thing not always in the desirable way. In all cases there is
a fraction of the time which represents getting oneself together after
being dropped in the box, and realizing where one is. But for our purpose
all these matters count little, and we may take the general slope of the
curve as representing very fairly the progress of the association. The
slope of any particular part of it may be due to accident. Thus, very
often the second experience may have a higher time-point than the first,
because the first few successes may all be entirely due to accidentally
hitting the loop, or whatever it is, and whether the accident will
happen sooner in one trial than another is then a matter of chance.
Considering the general slope, it is, of course, apparent that a gradual
descent—say, from initial times of 300 sec. to a constant time of 6 or 8
sec. in the course of 20 to 30 trials—represents a difficult association;
while an abrupt descent, say in 5 trials, from a similar initial height,
represents a very easy association. Thus, 2 in Z, on page 57, is a hard,
and 1 in I, on page 49, an easy association.
[Illustration: FIG. 3.]
In boxes A, C, D, E, I, 100 per cent of the cats given a chance to do so,
hit upon the movement and formed the association. The following table
shows the results where some cats failed:—
TABLE 1
NO. CATS TRIED NO. CATS FAILED
+---------------+---------------+
F | 5 | 4 |
G | 8 | 5 |
H | 9 | 2 |
J | 5 | 2 |
K | 5 | 2 |
+---------------+---------------+
The time-curves follow. By referring to the description of apparatus they
will be easily understood. Each mm. along the abscissa represents one
trial. Each mm. above it represents 10 seconds.
[Illustration: FIG. 4.]
[Illustration: FIG. 5.]
These time-curves show, in the first place, what associations are easy
for an animal to form, and what are hard. The act must be one which the
animal will perform in the course of the activity which its inherited
equipment incites or its previous experience has connected with the
sense-impression of a box’s interior. The oftener the act naturally
occurs in the course of such activity, the sooner it will be performed
in the first trial or so, and this is one condition, sometimes, of the
ease of forming the association. For if the first few successes are five
minutes apart, the influence of one may nearly wear off before the next,
while if they are forty seconds apart the influences may get summated.
But this is not the only or the main condition of the celerity with which
an association may be formed. It depends also on the amount of attention
given to the act. An act of the sort likely to be well attended to will
be learned more quickly. Here, too, accident may play a part, for a cat
may merely happen to be attending to its paw when it claws. The kind of
acts which insure attention are those where the movement which works the
mechanism is one which the cat makes definitely to get out. Thus A (O
at front) is easier to learn than C (button), because the cat does A in
trying to claw down the front of the box and so is attending to what it
does; whereas it does C generally in a vague scramble along the front
or while trying to claw outside with the other paw, and so does not
attend to the little unimportant part of its act which turns the button
round. Above all, _simplicity_ and _definiteness_ in the act make the
association easy. G (thumb latch), J (double) and K and L (triples) are
hard, because complex. E is easy, because directly in the line of the
instinctive impulse to try to pull oneself out of the box by clawing at
anything outside. It is thus very closely attended to. The extreme of
ease is reached when a single experience stamps the association in so
completely that ever after the act is done at once. This is approached in
I and E.
[Illustration: FIG. 6.]
In these experiments the sense-impressions offered no difficulty one more
than the other.
Vigor, abundance of movements, was observed to make differences between
individuals in the same association. It works by shortening the first
times, the times when the cat still does the act largely by accident.
Nos. 3 and 4 show this throughout. Attention, often correlated with lack
of vigor, makes a cat form an association more quickly after he gets
started. No. 13 shows this somewhat. The absence of a fury of activity
let him be more conscious of what he did do.
[Illustration: FIG. 7.]
The curves on pages 57 and 58, showing the history of cats 1, 5, 13 and
3, which were let out of the box Z when they licked themselves, and of
cats 6, 2 and 4, which were let out when they scratched themselves, are
interesting because they show associations where there is no congruity
(no more to a cat than to a man) between the act and the result. One
chick, too, was thus freed whenever he pecked at his feathers to dress
them. He formed the association, and would whirl his head round and poke
it into his feathers as soon as dropped in the box. There is in all these
cases a noticeable tendency, of the cause of which I am ignorant, to
diminish the act until it becomes a mere vestige of a lick or scratch.
After the cat gets so that it performs the act soon after being put in,
it begins to do it less and less vigorously. The licking degenerates into
a mere quick turn of the head with one or two motions up and down with
tongue extended. Instead of a hearty scratch, the cat waves its paw up
and down rapidly for an instant. Moreover, if sometimes you do not let
the cat out after this feeble reaction, it does not at once repeat the
movement, as it would do if it depressed a thumb piece, for instance,
without success in getting the door open. Of the reason for this
difference I am again ignorant.
Previous experience makes a difference in the quickness with which the
cat forms the associations. After getting out of six or eight boxes by
different sorts of acts the cat’s general tendency to claw at loose
objects within the box is strengthened and its tendency to squeeze
through holes and bite bars is weakened; accordingly it will learn
associations along the general line of the old more quickly. Further,
its tendency to pay attention to what it is doing gets strengthened,
and this is something which may properly be called a change in degree
of intelligence. A test was made of the influence of experience in this
latter way by putting two groups of cats through I (lever), one group (1,
2, 3, 4, 5) after considerable experience, the other (10, 11, 12) after
experience with only one box. As the act in I was not along the line
of the acts in previous boxes, and as a decrease in the squeezings and
bitings would be of little use in the box as arranged, the influence of
experience in the former way was of little account. The curves of all are
shown on page 49.
[Illustration: FIG. 8.]
If the whole set of curves are examined in connection with the following
table, which gives the general order in which each animal took up the
different associations which he eventually formed, many suggestions
of the influence of experience will be met with. The results are not
exhaustive enough to justify more than the general conclusion that there
is such an influence. By taking more individuals and thus eliminating all
other factors besides experience, one can easily show just how and how
far experience facilitates association.
When, in this table, the letters designating the boxes are in italics it
means that, though the cat formed the association, it was in connection
with other experiments and so is not recorded in the curves.
TABLE 2
+------+-------------------------------+
|Cat 1 | _A_ _B_ _C_ _D₁_ _D_ Z I |
|Cat 2 | _C_ _D₁_ _D_ E Z H J I K |
|Cat 3 | A C E G H J Z I K |
|Cat 4 | C F G D Z H J I K |
|Cat 5 | C E Z H I |
|Cat 6 | _A_ _C_ E Z |
|Cat 7 | _A_ _C_ |
|Cat 10| C I A H D L |
|Cat 11| C I A H D L |
|Cat 12| C I A H D L |
|Cat 13| A C D G Z |
+------+-------------------------------+
[Illustration: FIG. 9.]
The advantage due to experience in our experiments is not, however,
the same as ordinarily in the case of trained animals. With them the
associations are with the acts or voice of man or with sense-impressions
to which they naturally do not attend (_e.g._ figures on a blackboard,
ringing of a bell, some act of another animal). Here the advantage of
experience is mainly due to the fact that by such experience the animals
gain the habit of attending to the master’s face and voice and acts and
to sense-impressions in general.
I made no attempt to find the differences in ability to acquire
associations due to age or sex or fatigue or circumstances of any
sort. By simply finding the average slope in the different cases to be
compared, one can easily demonstrate any such differences that exist. So
far as this discovery is profitable, investigation along this line ought
now to go on without delay, the method being made clear. Of differences
due to differences in the species, genus, etc., of the animals I will
speak after reviewing the time-curves of dogs and chicks.
In the present state of animal psychology there is another value to
these results which was especially aimed at by the investigator from the
start. They furnish a quantitative estimate of what the average cat can
do, so that if any one has an animal which he thinks has shown superior
intelligence or perhaps reasoning power, he may test his observations and
opinion by taking the time-curves of the animal in such boxes as I have
described.
[Illustration: FIG. 10.]
If his animal in a number of cases forms the associations very much more
quickly, or deals with the situation in a more intelligent fashion than
my cats did, then he may have ground for claiming in his individual a
variation toward greater intelligence and, possibly, intelligence of a
different order. On the other hand, if the animal fails to rise above the
type in his dealings with the boxes, the observer should confess that his
opinion of the animal’s intelligence may have been at fault and should
look for a correction of it.
We have in these time-curves a fairly adequate measure of what the
ordinary cat can do, and how it does it, and in similar curves soon to
be presented a less adequate measure of what a dog may do. If other
investigators, especially all amateurs who are interested in animal
intelligence, will take other cats and dogs, especially those supposed
by owners to be extraordinarily intelligent, and experiment with them in
this way, we shall soon get a notion of how much variation there is among
animals in the direction of more or superior intelligence. The beginning
here made is meager but solid. The knowledge it gives needs to be much
extended. The variations found in individuals should be correlated, not
merely with supposed superiority in intelligence, a factor too vague to
be very serviceable, but with observed differences in vigor, attention,
memory and muscular skill. No phenomena are more capable of exact and
thorough investigation by experiment than the associations of animal
consciousness. Never will you get a better psychological subject than a
hungry cat. When the crude beginnings of this research have been improved
and replaced by more ingenious and adroit experimenters, the results
ought to be very valuable.
Surely every one must agree that no man now has a right to advance
theories about what is in animals’ minds or to deny previous theories
unless he supports his thesis by systematic and extended experiments. My
own theories, soon to be proclaimed, will doubtless be opposed by many.
I sincerely hope they will, provided the denial is accompanied by actual
experimental work. In fact, I shall be tempted again and again in the
course of this book to defend some theory, dubious enough to my own mind,
in the hope of thereby inducing some one to oppose me and in opposing me
to make the experiments I have myself had no opportunity to make yet.
Probably there will be enough opposition if I confine myself to the
theories I feel sure of.
[Illustration: FIG. 11.]
EXPERIMENTS WITH DOGS
The boxes used were as follows:
AA was similar to A (O at front), except that the loop was of stiff cord
⅜ inch in diameter and was larger (3½ inches diameter); also it was hung
a foot from the floor and 8 inches to the right of the door. The box
itself was 41 × 20 × 23.
BB was similar to B, the loop being the same as in AA, and being hung a
foot from the floor. The box was of the same size and shape as AA.
BB1 was like BB, but the loop was hung 18 inches from the floor.
CC was similar to C (button), but the button was 6 inches long, and the
box was 36½ × 22 × 23.
II was similar to I, but the box was 30 × 20 × 25 inches; the door (11
inches wide, 6 high) was in the left front corner, and the lever was 6
inches long and entered the box at a point 2 inches to the right of the
door and 4 inches above the floor.
[Illustration: FIG. 12.]
In M the same box as in II was used, but instead of a lever projecting
inside the box, a lever running outside parallel to the plane of the
front of the box and 18 inches long was used. This lay close against the
bars composing the front of the box, and could be pawed down by sticking
the paw out an inch or so between two bars, at a point about 15 inches
high and 6 inches in from the right edge of the front. We may call M
‘_Lever outside_.’
[Illustration: FIG. 13.]
N was a pen 5 × 3 feet made of wire netting 46 inches high. The door, 31
× 20, was in the right half of the front. A string from the bolt passed
up over a pulley and back to the back center, where it was fastened 33
inches above the floor. Biting or pawing this string opened the door.
O was like K, except that there was only one bar, that the string ran
inside the box, so that it was easily accessible, and that the bolt
raised in K by depression of the platform could be raised in O (and was
by the dog experimented on) by sticking the muzzle out between two bars
just above the bolt and by biting the string, at the same time jerking it
upward. O was 30 × 20 × 25 in size.
The box G was used for both dogs and cats, without any variation save
that for dogs the resistance of the door to pressure outwards was doubled.
In these boxes were put in the course of the experiments dog 1 (about 8
months old), and dogs 2 and 3, adults, all of small size.
A dog who, when hungry, is shut up in one of these boxes is not nearly
so vigorous in his struggles to get out as is the young cat. And even
after he has experienced the pleasure of eating on escape many times he
does not try to get out so hard as a cat, young or old. He does try to
a certain extent. He paws or bites the bars or screening, and tries to
squeeze out in a tame sort of way. He gives up his attempts sooner than
the cat, if they prove unsuccessful. Furthermore his attention is taken
by the food, not the confinement. He wants to get _to_ the food, not _out
of_ the box. So, unlike the cat, he confines his efforts to the front
of the box. It was also a practical necessity that the dogs should be
kept from howling in the evening, and for this reason I could not use
as motive the utter hunger which the cats were made to suffer. In the
morning, when the experiments were made, the dogs were surely hungry,
and no experiment is recorded in which the dog was not in a state to be
willing to make a great effort for a bit of meat, but the motive may not
have been even and equal throughout, as it was with the cats.
[Illustration: FIG. 14.]
The curves on page 60 are to be interpreted in the same way as those for
the cats, and are on the same scale. The order in which No. 1 took up the
various associations was AA, BB, BB1, G, N, CC, II, O.
The percentage of dogs succeeding in the various boxes is given below,
but is of no consequence, because so few were tried, and because the
motive, hunger, was not perhaps strong enough, or equal in all cases.
In AA 3 out of 3.
In BB 0 out of 2 (that is, without previous experience of AA).
In CC 1 out of 2.
In II 3 out of 3.
In M 1 out of 2.
In N 1 out of 3.
In G 1 out of 3.
EXPERIMENTS WITH CHICKS
The apparatus was as follows:
[Illustration: FIG. 15. FIG. 16. FIG. 17.]
P was simply a small pen arranged with two exits, one leading to the
inclosure where were the other chicks and food, one leading to another
pen with no exit. The drawing (Fig. 15 on this page) explains itself. A
chick was placed at A and left to find its way out. The walls were made
of books stuck up on end.
Q was a similar pen arranged so that the real exit was harder to find.
(See Fig. 16.)
R was still another pen similarly constructed, with four possible avenues
to be taken. (See Fig. 17.)
S was a pen with walls 11 inches high. On the right side an inclined
plane of wire screening led from the floor of the pen to the top of its
front wall. Thence the chick could jump down to where its fellows and the
food and drink were. S was 17 × 14 in size.
T was a pen of the same size as S, with a block of wood 3 inches by 3
and 2 inches high in the right back corner. From this an inclined plane
led to the top of the front wall (on the right side of the box). But a
partition was placed along the left edge of this plane, so that a chick
could reach it only _via_ the wooden block, not by a direct jump.
U was a pen 16 × 14 × 10 inches. Along the back toward the right corner
were placed a series of steps 1½ inches wide, the first 1, the second
2, and the third 3 inches high. In the corner was a platform 4 × 4, and
4 high, from which access to the top of the front wall of the pen could
be gained by scrambling up inside a stovepipe 11 inches long, inclined
upward at an angle of about 30°. From the edge of the wall the chick
could, of course, jump down to food and society. The top of the pen was
covered so that the chick could not from the platform jump onto the edge
of the stovepipe or the top of the pen wall. The only means of exit was
to go up the steps to the platform, up through the stovepipe to the front
wall, and then jump down.
The time-curves for chicks 90, 91, 92, 93, 94 and 95, all 2-8 days old
when experimented on, follow on page 65. The scale is the same as that
in the curves of the cats and dogs. Besides these simple acts, which any
average chick will accidentally hit upon and associate, there are, in
the records of my preliminary study of animal intelligence, a multitude
of all sorts of associations which some chicks have happened to form.
Chicks have escaped from confinement by stepping on a little platform in
the back of the box, by jumping up and pulling a string like that in D,
by pecking at a door, by climbing up a spiral staircase and out through
a hole in the wall, by doing this and then in addition walking across a
ladder for a foot to another wall from which they jump down, etc. Not
every chick will happen upon the right way in these cases, but the chicks
who did happen upon it all formed the associations perfectly after enough
trials.
The behavior of the chicks shows the same general character as that
of the cats, conditioned, of course, by the different nature of the
instinctive impulses. Take a chick put in T (inclined plane) for an
example. When taken from the food and other chicks and dropped into the
pen he shows evident signs of discomfort; he runs back and forth, peeping
loudly, trying to squeeze through any openings there may be, jumping up
to get over the wall, and pecking at the bars or screen, if such separate
him from the other chicks. Finally, in his general running around he goes
up the inclined plane a way. He may come down again, or he may go on up
far enough to see over the top of the wall. If he does, he will probably
go running up the rest of the way and jump down. With further trials he
gains more and more of an impulse to walk up an inclined plane when he
sees it, while the vain running and pecking, etc., are stamped out by the
absence of any sequent pleasure. Finally, the chick goes up the plane as
soon as put in. In scientific terms this history means that the chick,
when confronted by loneliness and confining walls, responds by those acts
which in similar conditions in nature would be likely to free him. Some
one of these acts leads him to the successful act, and the resulting
pleasure stamps it in. Absence of pleasure stamps all others out. The
case is just the same as with dogs and cats. The time-curves are shown in
Fig. 18.
Coming now to the question of differences in intelligence between
the different animals, it is clear that such differences are hard to
estimate accurately. The chicks are surely very much slower in forming
associations and less able to tackle hard ones, but the biggest part of
the difference between what they do and what the dogs and cats do is not
referable so much to any difference in intelligence as to a difference
in their bodily organs and instinctive impulses. As between dogs and
cats, the influence of the difference in quantity of activity, in the
direction of the instinctive impulses, in the versatility of the fore
limb, is hard to separate from the influence of intelligence proper.
The best practical tests to judge such differences in general would be
differences in memory, which are very easily got at, differences in the
delicacy and complexity attainable, and, of course, differences in the
slope of the curves for the same association. If all these tests agreed,
we should have a right to rank one animal above the other in a scale
of intelligence. But this whole question of grading is, after all, not
so important for comparative psychology as its popularity could lead
one to think. Comparative psychology wants first of all to trace human
intellection back through the phylum to its origin, and in this aim is
helped little by knowing that dogs are brighter than cats, or whales than
seals, or horses than cows. Further, the whole question of ‘intelligence’
should be resolved into particular inquiries into the development of
attention, activity, memory, etc.
[Illustration: FIG. 18.]
So far as concerns dogs and cats, I should decide that the former were
more generally intelligent. The main reason, however, why dogs seem to us
so intelligent is not a good reason for the belief. It is because, more
than any other domestic animal, they direct their attention to _us_, to
what we do, and so form associations connected with acts of ours.
Having finished our attempt to give a true description of the facts of
association, so far as observed from the outside, we may now progress to
discuss its inner nature. A little preface about certain verbal usages is
necessary before doing so. Throughout I shall use the word ‘animal’ or
‘animals,’ and the reader might fancy that I took it for granted that the
associative processes were the same in all animals as in these cats and
dogs of mine. Really, I claim for my animal psychology only that it is
the psychology of just these particular animals. What this warrants about
animals in general may be left largely to the discretion of the reader.
As I shall later say, it is probable that in regard to imitation and the
power of forming associations from a lot of free ideas, the anthropoid
primates are essentially different from the cats and dogs.
The reasons why I say ‘animals’ instead of ‘dogs and cats of certain
ages’ are two. I do think that the probability that the other mammals,
barring the primates, offer no objections to the theories here advanced
about dogs and cats is a very strong probability, strong enough to force
the burden of proof upon any one who should, for instance, say that
horse-goat psychology was not like cat-dog psychology in these general
matters. I should claim that, till the contrary was shown in any case,
my statements should stand for the mammalian mind in general, barring
the primates. My second reason is that I hate to burden the reader
with the disgusting rhetoric which would result if I had to insert
particularizations and reservations at every step. The word ‘animal’ is
too useful, rhetorically, to be sacrificed. Finally, inasmuch as most
of my theorizing will be in the line of denying certain relatively high
functions to animals, the evidence from cats and dogs is sufficient, for
they are from among the most intelligent animals, and functions of the
kind to be discussed, if absent in their case, are probably absent from
the others.
REASONING OR INFERENCE
The first great question is whether or not animals are ever led to do
any of their acts by reasoning. Do they ever conclude from inference
that a certain act will produce a certain desired result, and so do it?
The best opinion has been that they do not. The best interpretation of
even the most extraordinary performances of animals has been that they
were the result of accident and association or imitation. But it has
after all been only opinion and interpretation, and the opposite theory
persistently reappears in the literature of the subject. So, although
it is in a way superfluous to give the _coup de grâce_ to the despised
theory that animals reason, I think it is worth while to settle this
question once for all.
The great support of those who do claim for animals the ability to infer
has been their wonderful performances which resemble our own. These could
not, they claim, have happened by accident. No animal could learn to open
a latched gate by accident. The whole substance of the argument vanishes
if, as a matter of fact, animals do learn those things by accident.
_They certainly do._ In this investigation choice was made of the
intelligent performances described by Romanes in the following passages.
I shall quote at some length because these passages give an admirable
illustration of an attitude of investigation which this research will, I
hope, render impossible for any scientist in the future. Speaking of the
general intelligence of cats, Romanes says:
“Thus, for instance, while I have only heard of one solitary
case ... of a dog which, without tuition, divined the use of
a thumb latch so as to open a closed door by jumping on the
handle and depressing the thumb-piece, I have received some
half-dozen instances of this display of intelligence on the
part of cats. These instances are all such precise repetitions
of one another that I conclude the fact to be one of tolerably
ordinary occurrence among cats, while it is certainly rare
among dogs. I may add that my own coachman once had a cat
which, certainly without tuition, learnt thus to open a door
that led into the stables from a yard into which looked some
of the windows of the house. Standing at these windows when
the cat did not see me, I have many times witnessed her _modus
operandi_. Walking up to the door with a most matter-of-course
kind of air, she used to spring at the half hoop handle just
below the thumb latch. Holding on to the bottom of this
half-hoop with one fore paw, she then raised the other to the
thumb piece, and while depressing the latter finally with her
hind legs scratched and pushed the door posts so as to open the
door....
“Of course in all such cases the cats must have previously
observed that the doors are opened by persons placing their
hands upon the handles and, having observed this, the animals
act by what may be strictly termed rational imitation. But it
should be observed that the process as a whole is something
more than imitative. For not only would observation alone be
scarcely enough (within any limits of thoughtful reflection
that it would be reasonable to ascribe to an animal) to enable
a cat upon the ground to distinguish that the essential part
of the process consists not in grasping the handle, but in
depressing the latch; but the cat certainly never saw any one,
after having depressed the latch, pushing the door posts with
his legs; and that this pushing action is due to an originally
deliberate intention of opening the door, and not to having
accidentally found this action to assist the process, is shown
by one of the cases communicated to me; for in this case, my
correspondent says, ‘the door was not a loose-fitting one, by
any means, and I was surprised that by the force of one hind
leg she should have been able to push it open after unlatching
it.’ Hence we can only conclude that the cats in such cases
have a very definite idea as to the mechanical properties of
a door: they know that to make it open, even when unlatched,
it requires to be _pushed_—a very different thing from trying
to imitate any particular action which they may see to be
performed for the same purpose by man. The whole psychological
process, therefore, implied by the fact of a cat opening a
door in this way is really most complex. First the animal must
have observed that the door is opened by the hand grasping
the handle and moving the latch. Next she must reason, by
‘the logic of feelings’—‘If a hand can do it, why not a paw?’
Then strongly moved by this idea she makes the first trial.
The steps which follow have not been observed, so we cannot
certainly say whether she learns by a succession of trials that
depression of the thumb piece constitutes the essential part
of the process, or, perhaps more probably, that her initial
observations supplied her with the idea of clicking the thumb
piece. But, however this may be, it is certain that the pushing
with the hind feet after depressing the latch must be due to
adaptive reasoning unassisted by observation; and only by the
concerted action of all her limbs in the performance of a
highly complex and most unnatural movement is her final purpose
attained.” (Animal Intelligence, pp. 420-422.)
A page or two later we find a less ponderous account of a cat’s success
in turning aside a button and so opening a window:—
“At Parara, the residence of Parker Bowman, Esq., a full-grown
cat was one day accidentally locked up in a room without any
other outlet than a small window, moving on hinges, and kept
shut by means of a swivel. Not long afterwards the window was
found open and the cat gone. This having happened several
times, it was at last found that the cat jumped upon the window
sill, placed her fore paws as high as she could reach against
the side, deliberately reached with one over to the swivel,
moved it from its horizontal to a vertical position, and then,
leaning with her whole weight against the window, swung it open
and escaped.” (Animal Intelligence, p. 425.)
A description has already been given on page 31 of the small box (C),
whose door fell open when the button was turned, and also of a large
box (CC) for the dogs, with a similar door. The thumb-latch experiment
was carried on with the same box (G) for both cats and dogs, but the
door was arranged so that a greater force (1.3 kilograms) was required
in the case of the dogs. It will be remembered that the latch was so
fixed that if the thumb piece were pressed down, without contemporaneous
outward pressure of the door, the latch bar would merely drop back into
its catch as soon as the paw was taken off the door. If, however, the
door were pushed outward, the latch bar, being pressed closely against
the outer edge of its catch, would, if lifted, be likely to fall outside
it and so permit the door to open if then or later sufficient pressure
were exerted. Eight cats (Nos. 1, 2, 3, 4, 5, 6, 7 and 13) were, one
at a time, left in this thumb-latch box. All exhibited the customary
instinctive clawings and squeezings and bitings. Out of the eight all
succeeded in the course of their vigorous struggles in pressing down
the thumb piece, so that if the door had been free to swing open, they
could have escaped. Six succeeded in pushing both thumb-piece down and
door out, so that the bar did not fall back into its place. Of these five
succeeded in also later pushing the door open, so that they escaped and
got the fish outside. Of these, three, after repeated trials, associated
the complicated movements required with the sight of the interior of the
box so firmly that they attacked the thumb latch the moment they were put
in. The history of the formation of the association in the case of 3 and
of 4 is shown in the curves in Figs. 6 and 7. In the case of 13 the exact
times were not taken. The combination of accidents required was enough to
make No. 1 and No. 6 take a long time to get out. Consequently, weariness
and failure inhibited their impulses to claw, climb, etc., more than the
rare pleasure from getting out strengthened them, and they failed to
form the association. Like the cats who utterly failed to get out, they
finally ceased to try when put in. The history of their efforts is as in
Table 3: the figures in the columns represent the time (in minutes and
seconds) the animal was in the box before escaping or before being taken
out if he failed to escape. Cases of failure are designated by an F after
the figures. Double lines represent an interval of twenty-four hours.
TABLE 3
+----------+---------+
| No. 1. | No. 6. |
+==========+=========+
| 13.00 F | 17.50 |
| 9.30 | 3.30 |
| 1.40 | 9.00 |
| .50 | 2.10 |
| 15.00 | 1.45 |
| 6.00 F | 1.55 |
+==========+ |
| 14.00 | 13.00 |
| +=========+
| 20.00 F | 5.00 |
| 4.30 | 2.30 |
| 20.00 F | 15.00 |
| 20.00 F | 10.00 F |
| +=========+
| 15.00 F | 5.00 |
+==========+ |
| 60.00 F | 15.00 F |
| +=========+
| | 10.00 F |
| +=========+
| | 10.00 F |
+----------+---------+
It should be noted that, although cats 3 and 4 had had some experience
in getting out of boxes by clawing at loops and turning buttons, they
had never had anything at all like a thumb latch to claw at, nor had
they ever seen the door opened by its use, nor did they even have any
experience of the fact that the part of the box where the thumb piece
was was the door. And we may insert here, what will be stated more fully
later, that there was displayed no observation of the surroundings or
deliberation upon them. It was just a mad scramble to get out.
Three dogs (1, 2 and 3) were given a chance to liberate themselves from
this same box. 2 and 3, who were rather inactive, failed to even push the
thumb piece down. No. 1, who was very active, did push it down at the
same time that she happened to be pushing against the door. She repeated
this and formed the association as shown in the curve on page 60. She had
had experience only of escaping by pulling a loop of string.
Out of 6 cats who were put in the box whose door opened by a button,
not one failed, in the course of its impulsive activity, to push the
button around. Sometimes it was clawed to one side from below; sometimes
vigorous pressure on the top turned it around; sometimes it was pushed
up by the nose. No cat who was given repeated trials failed to form a
perfect association between the sight of the interior of that box and
the proper movements. Some of these cats had been in other boxes where
pulling a loop of string liberated them, 3 and 4 had had considerable
experience with the boxes and probably had acquired a general tendency to
claw at loose objects. 10, 11 and 12 had never been in _any box_ before.
The curves are on pages 41 and 43.
Of two dogs, one, when placed in a similar but larger box, succeeded in
hitting the button in such a way as to let the door open, and formed
a permanent association, as shown by the curves on page 41. No one who
had seen the behavior of these animals when trying to escape could doubt
that their actions were directed by instinctive impulses, not by rational
observation. It is then absolutely sure that a dog or cat _can_ open a
door closed by a thumb latch or button, merely by the accidental success
of its natural impulses. If _all_ cats, when hungry and in a _small_ box,
will accidentally push the button that holds the door, an _occasional_
cat in a _large_ room may very well do the same. If three cats out of
eight will accidentally press down a thumb piece and push open a small
door, three cats out of a thousand may very well open doors or gates in
the same way.
But besides thus depriving of their value the facts which these
theorizers offer as evidence, we may, by a careful examination of
the method of formation of these associations as it is shown in the
time-curves, gain positive evidence that no power of inference was
present in the subjects of the experiments. Surely if 1 and 6 had
possessed any power of inference, they would not have failed to get
out after having done so several times. Yet they did. (See p. 71.) If
they had once even, much less if they had six or eight times, inferred
what was to be done, they should have made the inference the seventh or
ninth time. And if there were in these animals any power of inference,
however rudimentary, however sporadic, however dim, there should have
appeared among the multitude some cases where an animal, seeing through
the situation, knows the proper act, does it, and from then on does
it immediately upon being confronted with the situation. There ought,
that is, to be a sudden vertical descent in the time-curve. Of course,
where the act resulting from the impulse is very simple, very obvious,
and very clearly defined, a single experience may make the association
perfect, and we may have an abrupt descent in the time-curve without
needing to suppose inference. But if in a complex act, a series of
acts or an ill-defined act, one found such a sudden consummation in
the associative process, one might very well claim that reason was at
work. Now, the scores of cases recorded show no such phenomena. The
cat does not look over the situation, much less _think_ it over, and
then decide what to do. It bursts out at once into the activities which
instinct and experience have settled on as suitable reactions to the
situation ‘_confinement when hungry with food outside_.’ It does not
ever in the course of its successes realize that such an act brings
food and therefore decide to do it and thenceforth do it immediately
from _decision_ instead of from impulse. The one impulse, out of
many accidental ones, which leads to pleasure, becomes strengthened
and stamped in thereby, and more and more firmly associated with the
sense-impression of that box’s interior. Accordingly it is sooner and
sooner fulfilled. Futile impulses are gradually stamped out. The gradual
slope of the time-curve, then, shows the absence of reasoning. They
represent the wearing smooth of a path in the brain, not the decisions of
a rational consciousness.
In a later discussion of imitation further evidence that animals do not
reason will appear. For the present, suffice it to say, that a dog, or
cat, or chick, who does not in his own impulsive activity learn to escape
from a box by pulling the proper loop, or stepping on a platform, or
pecking at a door, will not learn it from seeing his fellows do so. They
are incapable of even the inference (if the process may be dignified by
that name) that what gives another food will give it to them also. So,
also, it will be later seen that an animal cannot learn an act by being
put through it. For instance, a cat who fails to push down a thumb piece
and push out the door cannot be taught by having one take its paw and
press the thumb piece down with it. This _could_ be learned by a certain
type of associative process without inference. _Were there inference, it
surely would be learned._
Finally, attention may be called to the curves which show the way that
the animal mind deals with a series of acts (_e.g._ curves for G, J, K,
L and O, found on pages 45 to 55 and 60). Were there any reasoning the
animals ought early to master the method of escape in these cases (see
descriptions on pages 31 to 34) so as to do the several acts in order,
and not to repeat one after doing it once, or else ought utterly to fail
to master the thing. But, in all these experiments, where there was every
motive for the use of any reasoning faculty, if such existed, where the
animals literally lived by their intellectual powers, one finds no sign
of abstraction, or inference, or judgment.
So far I have only given facts which are quite uninfluenced by any
possible incompetence or prejudice of the observer. These alone seem
to disprove the existence of any rational faculty in the subjects
experimented on. I may add that my observations of all the conduct of all
these animals during the months spent with them, failed to find any act
that even _seemed_ due to reasoning. I should claim that this quarrel
ought now to be dropped for good and all,—that investigation ought to
be directed along more sensible and profitable lines. I should claim
that the psychologist who studies dogs and cats in order to defend this
‘reason’ theory is on a level with a zoölogist who should study fishes
with a view to supporting the thesis that they possessed clawed digits.
The rest of this account will deal with more promising problems, of
which the first, and not the least important, concerns the facts and
theories of _imitation_.
IMITATION
To the question, ‘Do animals imitate?’ science has uniformly answered,
‘Yes.’ But so long as the question is left in this general form, no
correct answer to it is possible. It will be seen, from the results
of numerous experiments soon to be described, that imitation of a
certain sort is not possible for animals, and before entering upon that
description it will be helpful to differentiate this matter of imitation
into several varieties or aspects. The presence of some sorts of
imitation does not imply that of other sorts.
There are, to begin with, the well-known phenomena presented by the
imitative birds. The power is extended widely, ranging from the parrot
who knows a hundred or more articulate sounds to the sparrow whom a
patient shoemaker taught to get through a tune. Now, if a bird really
gets a sound in his mind from hearing it and sets out forthwith to
imitate it, as mocking birds are said at times to do, it is a mystery and
deserves closest study. If a bird, out of a lot of random noises that it
makes, chooses those for repetition which are like sounds that he has
heard, it is again a mystery _why_, though not as in the previous case a
mystery _how_, he does it. The important fact for our purpose is that,
though the imitation of sounds is so habitual, there does not appear to
be any marked general imitative tendency in these birds. There is no
proof that parrots do muscular acts from having seen other parrots do
them. But this should be studied. At any rate, until we know what sort of
sounds birds imitate, what circumstances or emotional attitudes these
are connected with, how they learn them and, above all, whether there is
in birds which repeat sounds any tendency to imitate in other lines, we
cannot, it seems to me, connect these phenomena with anything found in
the mammals or use them to advantage in a discussion of animal imitation
as the forerunner of human. In what follows they will be left out of
account, will be regarded as a specialization removed from the general
course of mental development, just as the feathers or right aortic
arch of birds are particular specializations of no consequence for the
physical development of mammals. For us, henceforth, imitation will mean
imitation minus the phenomena of imitative birds.
There are also certain pseudo-imitative or semi-imitative phenomena which
ought to be considered by themselves. For example, the rapid loss of
the fear of railroad trains or telegraph wires among birds, the rapid
acquisition of arboreal habits among Australian rodents, the use of
proper feeding grounds, etc., may be held to be due to imitation. The
young animal stays with or follows its mother from a specific instinct to
keep near that particular object, to wit, its mother. It may thus learn
to stay near trains, or scramble up trees, or feed at certain places and
on certain plants. Actions due to following pure and simple may thus
simulate imitation. Other groups of acts which now seem truly imitative
may be indirect fruits of some one instinct. This must be kept in mind
when one estimates the supposed imitation of parents by young. Further,
it is certain that in the case of the chick, where early animal life has
been carefully observed, instinct and individual experience between them
rob imitation of practically all its supposed influence. Chicks get along
without a mother very well. Yet no mother takes more care of her children
than the hen. Care in other cases, then, need not mean instruction
through imitation.
These considerations may prevent an unreserved acceptance of the common
view that young animals get a great number of their useful habits from
imitation, but I do not expect or desire them to lead to its summary
rejection. I should not now myself reject it, though I think it quite
possible that more investigation and experiment may finally reduce all
the phenomena of so-called imitation of parents by young to the level of
indirect results of instinctive acts.
Another special department of imitation may be at least vaguely marked
off: namely, apparent imitation of certain limited sorts of acts which
are somewhat frequent in the animal’s life. An example will do better
than further definition.
Some sheep were being driven on board ship one at a time. In the course
of their progress they had to jump over a hurdle. On this being removed
before all had passed it, the next sheep was seen to jump as if to get
over a hurdle, and so on for five or six, apparently sure evidence that
they imitated the action, each of the one in front. Now, it is again
possible that among gregarious animals there may be elaborate connections
in the nervous system which allow the sight of certain particular acts in
another animal to arouse the innervation leading to those acts, but that
these connections are _limited_. The reactions on this view are specific
responses to definite signals, comparable to any other instinctive or
associational reaction. The sheep jumps when he sees the other sheep
jump, not because of a general ability to do what he sees done, but
because he is furnished with the instinct to jump at such a sight, or
because his experience of following the flock over boulders and brooks
and walls has got him into the habit of jumping at the spot where he
sees one ahead of him jump; and so he jumps even though no obstacle be
in his way. If due to instinct, the only peculiarity of such a reaction
would be that the sense-impression calling forth the act would be the
same act as done by another. If due to experience, there would be an
exact correspondence to the frequent acts called forth _originally_ by
several elements in a sense-impression, one of which is essential, and
done _afterwards_ when only the _non-essentials_ are present. These two
possibilities have not been sufficiently realized, yet they may contain
the truth. On the other hand, these limited acts may be the primitive,
sporadic beginnings of the general imitative faculty which we find in
man. To this general faculty we may now turn, having cleared away some of
the more doubtful phenomena which have shared its name.
It should be kept in mind that an imitative act may be performed quite
unthinkingly, as when a man in the mob shouts what the others shout or
claps when the others clap; may be done from an inference that since A
by doing X makes pleasure for himself, I by doing X may get pleasure
for myself; may, lastly, be done from what may be called a transferred
association. This process is the one of interest in connection with our
general topic, and most of my experiments on imitation were directed to
the investigation of it. Its nature is simple. One sees the following
sequence: ‘A turning a faucet, A getting a drink.’ If one can free this
association from its narrow confinement to A, so as to get from it the
association, ‘impulse to turn faucet, _me_ getting a drink,’ one will
surely, if thirsty, turn the faucet, though he had never done so before.
If one can from an act witnessed learn to do the act, he in some way
makes use of the sequence seen, transfers the process to himself; in the
common human sense of the word, he _imitates_. This kind of imitation
is surely common in human life. It may be apparent in ontogeny before
any power of inference is shown. After that power does appear, it still
retains a wide scope, and teaches us a majority, perhaps, of the ordinary
accomplishments of our practical life.
Now, as the writers of books about animal intelligence have not
differentiated this meaning from the other possible ones, it is
impossible to say surely that they have uniformly credited it to animals,
and it is profitless to catalogue here their vague statements. Many
opposers of the ‘reason’ theory have presupposed such a process and used
it to replace reason as the cause of some intelligent performances. The
upholders of the reason theory have customarily recognized such a process
and claimed to have discounted it in their explanations of the various
anecdotes. So we found Mr. Romanes, in the passage quoted, discussing the
possibility that such an imitative process, without reason, could account
for the facts. In his chapter on Imitation in ‘Habit and Instinct,’
Principal C. Lloyd Morgan, the sanest writer on comparative psychology,
seems to accept imitation of this sort as a fact, though he could, if
attacked, explain most of his illustrations by the simple forms. The fact
is, as was said before, that no one has analyzed or systematized the
phenomena, and so one cannot find clear, decisive statements to quote.
At any rate, whether previous authorities have agreed that such a process
is present or not, it is worth while to tackle the question; and the
formation of associations by imitation, if it occurs, is an important
division of the formation of associations in general. The experiments and
their results may now be described.
IMITATION IN CHICKS
No. 64 learned to get out of a certain pen (16 × 10 inches) by crawling
under the wire screening at a certain spot. There was also a chance to
get out by walking up an inclined plane and then jumping down. No. 66 was
put in with 64. After 9 minutes 20 seconds, 66 went out by the inclined
plane, although 64 had in the meantime crawled out under the screen 9
times. (As soon as he got out and ate a little he was put back.) It was
impossible to judge how many of these times 66 really saw 64 do this.
He was looking in that direction 5 of the times. So also, in three more
trials, 66 used the inclined plane, though 64 crawled under each time. 67
was then tried. In 4 minutes 10 seconds, he crawled under, 64 having done
so twice. Being then put in _alone_, he, without the chance to imitate,
still crawled under. So probably he went under _when with 64_ not by
imitation but by accident, just as 64 had learned the thing himself.
[Illustration: Fig. 19. Fig. 20.]
The accompanying figure (19) shows the apparatus used in the next
experiment. A represents the top of a box (5 × 4 inches), 13 inches above
the level of the floor C. On the floor C were the chicks and food. B is
the top of a box 10 inches high. Around the edges of A except the one
next B a wire screen was placed, and 65 was repeatedly put upon A until
he learned to go quickly back to C _via_ B. Then the screen was bent
outward at X so that a chick could barely squeeze through and down (A to
C). Eleven chicks were then one at a time placed on A with 65. In every
case but one they went A-C. In the case of the chick (75) who went A-B-C,
there could have been no imitation, for he went down _before_ 65 did. One
other went through the hole before 65 went to B. The remaining nine all
had a chance to imitate 65 and to save the uncomfortable struggle to get
through the hole, 65 going A-B-C 8 times before 68 went A-C, 2 times when
with 66 and 76, once in the case of each of the others.
In still another experiment the apparatus was (as shown in Fig. 20) a
pen 14 inches square, 10 inches high, with a wire screen in front and a
hole 3½ inches square in the back. This hole opened into a passageway (B)
leading around to C, where were the other chicks and food. Chicks who had
failed, when put in alone, to find the way out, were put in with other
chicks who had learned the way, to see if by seeing them go out they
would learn the way. Chick 70 was given 4 trials alone, being left in the
box 76 minutes all told. He was then given 9 trials (165 minutes) with
another chick who went out _via_ B 36 times. 70 failed to follow him on
any occasion. The trials were all given in the course of two days. Chick
73 failed in 1 trial (12 minutes) to get out of himself, and was then
given 4 trials (94 minutes) with another chick who went out _via_ B 33
times. In this experiment, as in all others reported, sure evidence that
the animals wanted to get out, was afforded by their persistent peckings
and jumpings at the screen or bars that stood between them and C. Chick
72, after 8 unsuccessful trials alone (41 minutes), was given 8 trials
with a chance to imitate. After the other chick had gone out 44 times,
72 _did go out_. He did not follow the other but went 20 seconds later.
It depends upon one’s general opinion whether one shall attribute this
one case out of three to accident or imitation.
I also took two chicks, one of whom learned to escape from A (in Fig. 19)
by going to B and jumping down the side to the _right_ of A, the other
of whom learned to jump down the side to the _left_, and placed them
together upon A. Each took his own course uninfluenced by the other in 10
trials.
Chicks were also tried in several pens where there was only one possible
way of escape to see if they would learn it _more quickly_ when another
chick did the thing several times before their eyes. The method was
to give some chicks their first trial with an imitation possibility
and their second without, while others were given their first trial
without and their second with. If the ratio of the average time of the
first trial to the average time of the second is smaller in the first
class than it is in the second class, we may find evidence of this
sort of influence by imitation. Though imitation may not be able to
make an animal _do_ what he would otherwise _not do_, it may make him
do _quicker_ a thing he would have done sooner or later any way. As a
fact the ratio is _much larger_. This is due to the fact that a chick,
when in a pen with another chick, is not afflicted by the discomfort
of loneliness, and so does not try so hard to get out. So the other
chick, who is continually being put in with him to teach him the way
out, really prolongs his stay in. This factor destroys the value of
these quantitative experiments, and I do not insist upon them as
evidence against imitation, though they certainly offer none for it. I
do not give descriptions of the apparatus used in these experiments or
a detailed enumeration of the results, because in this discussion we
are not dealing primarily with imitation as a slight general factor
in forming experience, but as a definite associational process in the
mind. The utter absence of imitation in this limited sense is apparently
demonstrated by the results of the following experiments.
V was a box 16 × 12 × 8½, with the front made of wire screening and at
the left end a little door held by a bolt but in such a way that a sharp
peck at the top of the door would force it open.
W was a box of similar size, with a door in the same place fixed so that
it was opened by raising a bolt. To this bolt was tied a string which
went up over the top of the edge of the box and back across the box, as
in D. By jumping up and coming down with the head over this thread, the
bolt would be pulled up. The thread was 8½ inches above the floor.
X was a box of similar size, with door, bolt and string likewise. But
here the string continued round a pulley at the back down to a platform
in the corner of the box. By stepping on the platform the door was opened.
Y was a box 12 × 8 × 8½, with a door in the middle of the front, which I
myself opened when a chick pecked at a tack which hung against the front
of the box 1½ inches above the top of the door.
These different acts, pecking at a door, jumping up and with the neck
pulling down a string, stepping on a platform, and pecking at a tack,
were the ones which various chicks were given a chance to imitate. The
chicks used were from 16 to 30 days old. The method of experiment was
to put a chick in, leave him 60 to 80 seconds, then put in another who
knew the act, and on his performing it, to let both escape. No cases were
counted unless the imitator apparently saw the other do the thing. After
about ten such chances to learn the act, the imitator was left in alone
for ten minutes. The following table gives the results. The imitators,
of course, had previously failed to form the association of themselves. F
denotes failure to perform the act:
TABLE 4
======+=====+=========+============+==============
| |NO. TIMES| TIME IN |
CHICK | ACT | SAW |WHICH FAILED| FINAL TIME
------+-----+---------+------------+--------------
84 | V | 38 | 45.00 F | 15.00 F
85 | V | 30 | 30.00 F | 10.00 F
86 | V | 44 | 55.00 F | 15.00 F
87 | V | 26 | 35.00 F | 15.00 F
80 | W | 54 | 60.00 F | 15.00 F
81 | W | 40 | 45.00 F | 15.00 F
87 | W | 27 | 30.00 F | 10.00 F
81 | X | 18 | 20.00 F | 10.00 F
82 | X | 21 | 20.00 F | 8.40 _Did_
83 | X | 33 | 35.00 F | 15.00 F
84 | X | 46 | 55.00 F | 15.00 F
84 | Y | 45 | 55.00 F | 15.00 F
83 | Y | 29 | 35.00 F | 15.00 F
======+=====+=========+============+==============
Thus out of all these cases only one did the act in spite of the ample
chance for imitation. I have no hesitation in declaring 82’s act in
stepping on the platform the result of mere accident, and am sure that
any one who had watched the experiments would agree.
IMITATION IN CATS
By reference to the previous descriptions of apparatus, it will be seen
that box D was arranged with two compartments, separated by a wire
screen. The larger of these had a front of wooden bars with a door which
fell open when a string stretched across the top was bitten or clawed
down. The smaller was closed by boards on three sides and by the wire
screen on the fourth. Through the screen a cat within could see the one
to be imitated pull the string, go out through the door thus opened and
eat the fish outside. When put in this compartment, the top being covered
by a large box, a cat soon gave up efforts to claw through the screen,
quieted down and watched more or less the proceedings going on in the
other compartment. Thus this apparatus could be used to test the power of
imitation. A cat who had no experience with the means of escape from the
large compartment was put in the closed one; another cat, who would do it
readily, was allowed to go through the performance of pulling the string,
going out, and eating the fish. Record was made of the number of times he
did so and of the number of times the imitator had his eyes clearly fixed
on him. These were called ‘times seen.’ Cases where the imitator was
looking in the general direction of the ‘imitatee’ and might very well
have seen him and probably did, were marked ‘doubtful.’ In the remaining
cases the cat did not see what was done by his instructor. After the
imitatee had done the thing a number of times, the other was put in the
big compartment alone, and the time it took him before pulling the string
was noted and his general behavior closely observed. If he failed in 5
or 10 or 15 minutes to do so, he was released and not fed. This entire
experiment was repeated a number of times. From the times taken by the
imitator to escape and from observation of the way that he did it, we can
decide whether imitation played any part. The history of several cases
are given in the following tables. In the first column are given the
lengths of time that the imitator was shut up in the box watching the
imitatee. In the second column is the number of times that the latter did
the trick. In the third and fourth are the times that the imitator surely
and possibly saw it done, while in the last is given the time that, when
tried alone, the imitator took to pull the string, or if he failed,
the time he was in the box trying to get out. Times are in minutes and
seconds, failures denoted by F:
TABLE 5 (a)
=======================+=====================================+===========
| NO. 7 IMITATING NO. 2 |
--------------+--------+------------+-----------+------------+-----------
| Time |No. of times| No. of |No. of times| Time of 7
|Watching| 2 did |times 7 saw| Doubtful |when alone
--------------+--------+------------+-----------+------------+-----------
| 10.00 | 11 | 3 | 5 |
After 48 Hours| 11.00 | 10 | 4 | 2 |
| 12.00 | 20 | 4 | 13 | 10.00 F
| | | | | 1.00[8]
After 24 Hours| 8.00 | 20 | 6 | 11 | 3.30
| | | | | 10.00 F
| 13.00 | 25 | 8 | 12 | 20.00 F
After 24 Hours| 9.00 | 20 | 4 | 11 | 10.00 F
After 24 Hours| 12.00 | 35 | 5 | 21 | 30.00 F
After 2 Hours | 10.00 | 25 | 3 | 8 | 25.00 F
After 24 Hours| 15.00 | 35 | 6 | 21 | 20.00 F
After 24 Hours| 6.00 | 20 | 0 | 7 | 10.00 F
Total times surely and possibly seen,— 43 111 |
=============================================================+===========
TABLE 5 (b)
=======================+=====================================+===========
| NO. 5 IMITATING NO. 2 |
--------------+--------+------------+-----------+------------+-----------
| Time |No. of times| No. of |No. of times| Time of 5
|Watching| 2 did |times 5 saw| Doubtful |when alone
--------------+--------+------------+-----------+------------+-----------
| 12.00 | 15 | 3 | 8 | 5.00 F
After 2 Hours| 10.00 | 8 | 4 | 4 |
After 24 Hours| 5.00 | 5 | 0 | 3 |
After 1 Hour | 14.00 | 10 | 5 | 3 | 10.00 F
After 1 Hour | 13.00 | 22 | 7 | 11 | 10.00 F
After 24 Hours| 7.00 | 15 | 3 | 8 | 5.00 F
After 48 Hours| 18.00 | 20 | 2 | 9 | 20.00 F
After 24 Hours| 14.00 | 20 | 2 | 10 | 30.00 F
After 24 Hours| 10.00 | 20 | 7 | 12 | 20.00 F
Total times surely and possibly seen,— 33 68 |
=============================================================+===========
TABLE 5 (c)
=======================+=====================================+===========
| NO. 6 IMITATING NO. 2 |
--------------+--------+------------+-----------+------------+-----------
| Time |No. of times| No. of |No. of times| Time of 6
|Watching| 2 did |times 6 saw| Doubtful |when alone
--------------+--------+------------+-----------+------------+-----------
| 12.00 | 30 | 0 | 19 | 1.10[9]
After 48 Hours| 11.00 | 30 | 0 | 11 | 9.30
After 72 Hours| 10.00 | 30 | 0 | 15 | 3.00
After 72 Hours| 6.00 | 20 | 3 | 7 | 1.50
After 24 Hours| 9.00 | 30 | 1 | 13 | 10.00 F
After 24 Hours| 10.00 | 30 | 6 | 9 | 10.00 F
After 24 Hours| 10.00 | 30 | 1 | 8 | 9.40
Total times surely and possibly seen,— 11 82 |
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TABLE 5 (d)
=======================+=====================================+===========
| NO. 3 IMITATING NO. 2 |
--------------+--------+------------+-----------+------------+-----------
| 8.00 | 30 | 2 | 19 | 3.30[10]
| | | | | 3.30
After 48 Hours| 10.00 | 30 | 2 | 14 | .20
| | | | | .20
After 72 Hours| 10.00 | 30 | 2 | 8 | .18
| | | | | .08
Total times surely and possibly seen,— 6 41 |
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Before entering upon a discussion of the facts shown by these tables,
we must describe the behavior of the imitators, when, after seeing 2
pull the string, they were put in alone. In the opinion of the present
observer there was not the slightest difference between their behavior
and that of cats 4, 10, 11, 12 and 13, who were put into the same
position without ever having seen 2 escape from it. 6, 7, 5 and 3 paid
no more attention to the string than they did, but struggled in just
the same way. No one, I am sure, who had seen them, would have claimed
that their conduct was at all influenced by what they had seen. When
they did hit the string the act looked just like the accidental success
of the ordinary association experiment. But, besides these personal
observations, we have in the impersonal time-records sufficient proofs
of the absence of imitation. If the animals pulled the string from
having seen 2 do so, they ought to pull it in each individual case at
an approximately regular length of time after they were put in, and
presumably pretty soon thereafter. That is, if an association between
the sight of that string in that total situation and a certain impulse
and consequent freedom and food had been formed in their minds by the
observation of the acts of 2, they ought to pull it _on seeing it_, and
if any disturbing factor required that a certain time should elapse
before the imitative faculty got in working order, that time ought to be
somewhere near constant. The times were, as a fact, long and irregular
in the extreme. Furthermore, if the successful cases were even in part
due to imitation, the times ought to decrease the more they saw 2 do the
thing. Except with 3, they _increase_ or give place to failures. Whereas
6 and 7, if they had been put in again immediately after their first
successful trial and from then on repeatedly, would have unquestionably
formed the association, they did not, when put in after a further
chance to increase their knowledge by imitation, do the thing as soon
as before. The case of 3 is not here comparable to the rest because he
_was_ given three trials in immediate succession. He was a more active
cat and quicker to learn, as may be seen by comparing his time curves
with those of 7, 6 and 5. That the mere speed with which he mastered
this association is no sign that imitation was present may be seen by
reference to the time curves of 4 and 13 (on p. 43).
Some cats were also experimented with in the following manner. They were
put into a box [No. 7 into box A (O at front), No. 5 into B (O at back)]
and left for from 45 to 75 seconds. Then a cat who knew the way to get
out was put in, and, of course, pulled at the loop and opened the door.
_Both cats then went out and both were fed._ After the cat had been
given a number of such chances to learn by imitation, he was put in and
left until he did the thing, or until 5 or 10 minutes elapsed. As in the
preceding experiments, no change in their behavior which might signify
imitation was observed. No. 7 acted exactly like 3, or 10, or 11, when
put in the box, apparently forming the association by accident in just
the same way. Good evidence that he did not imitate is the fact that,
whereas 1 (whom he saw) pulled the loop with his teeth, 7 pulled it with
his paw. 5 failed to form the association, though he saw 3 do it 8 times
and probably saw him 18 times more. He did get out twice by clawing the
_string_ in the _front_ of the box, not the _loop_ in the _back_, as 3
did. These successes took place early in the experiment. After that he
failed when left alone to get out at all.
Another experiment was made by a still different method. My cats were
kept in a large box about 4 ft. high, the front of which was covered with
poultry-yard netting. Its top was a board which could be removed. To save
opening the door and letting them all loose, I was in the habit of taking
them out by the top when I wanted to experiment with them. Of course the
one who happened to climb up (perhaps attracted by the smell of fish
on my fingers) was most likely to be taken out and experimented with
and fed. Thus they formed the habit of climbing up the front of the box
whenever I approached. Of three cats which I obtained at the same time,
one did not after 8 or 10 days acquire this habit. Even though I held out
a piece of fish through the netting, he would not climb after it. It was
reasonable to suppose that imitation might overcome this sluggishness,
if there were any imitation. I therefore put two cats with him and had
them climb up 80 times before his eyes and get fish. He never followed or
tried to follow them.
4 and 3 had been subjected to the following experiment. I would make a
certain sound and after 10 seconds would go up to the cage and hold the
fish out to them through the netting at the top. They would then, of
course, climb up and eat it. After a while, they began to climb up upon
hearing the signal (4) or before the 10 seconds were up. I then took 12
and 10, who were accustomed to going up when they saw me approach, but
who had no knowledge of the fact that the signal meant anything, and gave
them each a chance to imitate 3. That is, one of them would be left in
the box with 3, the signal would be given, and after from 5 to 10 seconds
3 would climb up. At 10 seconds I would come up with food, and then,
of course, 12 would climb up. This was repeated again and again. The
question was whether imitation would lead them to form the association
more quickly than they would have done alone. It did not. That when at
last they did climb up before 10 seconds was past, that is, before I
approached with food, it was not due to imitation, is shown by the fact
that on about half of such occasions they climbed up _before 3 did_. That
is, they reacted to the _signal_ by _association_, not to his _movements_
by _imitation_.
IMITATION IN DOGS
Here the method was not to see if imitation could arouse more quickly an
act which accident was fairly likely to bring forth sooner or later, but
to see if, where accident failed, imitation would succeed.
3 was found to be unable of himself to escape from box BB1, and was then
given a chance to learn from watching 1. The back of box BB1 was torn
off and wire netting substituted for it. Another box with open front was
placed directly behind and against box BB1. No. 3, who was put in this
second box, could thus see whatever took place in and in front of box BB1
(O at back, high). The record follows:—
TABLE 6 (a)