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.
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
| Chick | Act | No. Times Saw | Time in 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 Watching | No. of times 2 did | No. of times 7 saw | No. of times Doubtful | Time of 7 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 Watching | No. of times 2 did | No. of times 5 saw | No. of times Doubtful | Time of 5 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 Watching | No. of times 2 did | No. of times 6 saw | No. of times Doubtful | Time of 6 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 | ||||
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 | ||||
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.