of the animal, but becomes modified by the trial and error method. The functioning involved in the second type is radically different from that of the first. It implies the awakening of the impulse to repeat the model-act because of a more or less vivid recognition of its consequences. As Thorndike states it:
When the second type of imitation, voluntary imitation, appears there is necessarily a tremendous increase in surplus for all social animals possessing it. Thereafter any discovery made by one animal of a group may be transferred by a psychological process to all other animals in the group irrespective of whether they have been accustomed to perform that particular sequence of acts instinctively or not.
A most significant discovery has been made within the past fifteen years in the attempt to ascertain how far down the phylogenetic scale this power of voluntary imitation may be found. This discovery is that man alone possesses it to any considerable degree. Thorndike experimenting with chickens, cats and dogs found no evidence whatever of this type. Even his results with monkeys were, on the whole, negative. Small's rats showed no ability to profit by each other's experience in this way. According to Yerkes this type of imitation plays no considerable role in the learning processes of the dancing mouse. Hobhouse, to be sure, holds that cats, dogs, elephants and monkeys were aided in their learning if he "showed" them how to do a thing. Whether this was voluntary imitation, however, or whether the animals were merely aided in focusing their attention on the important object and thus received assistance by lessening the number of trials and errors, is a difficult question to answer. The past experience of the animals, moreover, was not always fully known in these experiments. Kinnaman's monkeys gave more positive results but, as Washburn says, we can not be sure that Kinnaman's monkeys really had an idea of the proper action suggested to them by seeing their companions perform it; the case might have been one of instinctive imitation, taking here a form more elaborate than was seen in cats and dogs because more compli-
- "An animal may perform an act the first time because, through inherited nervous connections, the sight of another animal's performing it acts as a stimulus. But it will continue to perform the act, in the absence of any copy to imitate, only if the act is itself an instinctive one, like drinking in birds, or becomes permanent by reason of its consequences, just as would be the case if its first performance had been accidental rather than imitative. As a matter of fact instinctive imitation seems usually to be concerned with actions themselves instinctive." Washburn, "Animal Mind," p. 238.
- "Animal Intelligence," p. 50.