In the case of the human child we may see the three stages in the development of vocal imitation. First, the instinctive stage, where the sound which falls upon the ear is a stimulus to the motor-mechanism of sound production. Secondly, the intelligent stage of the profiting by experience. Intelligence, as we have seen, aims at the reinstatement of pleasurable situations, and the suppression of those which are the reverse. The sound-stimulus, the motor effects in behaviour, and the resulting sound-production coalesce into a conscious situation, which appears to be pleasurable or the reverse, according as the sound produced resembles or not the initiating sound-stimulus. If we assume that the resemblance of the sounds he utters to the sounds he hears is itself a source of pleasurable satisfaction (and this certainly seems to be the case), intelligence, without the aid of any higher faculty, will secure accommodation and render imitation more and more perfect. And this appears to be the stage reached by the mocking-bird or the parrot. But the child soon goes further. He reflects upon the results he has reached; he at first dimly, and then more clearly realizes that they are imitative; and his later efforts at imitation are no longer subject to the chance occurrence of happy results, but are based on a scheme of behaviour which is taking form in his mind, are deliberate and intentional, and are directed to a special end more or less clearly perceived as such. He no longer imitates like a parrot; he begins to imitate like a man, and may, by the study of good models and the maintenance of a high ideal, acquire the moving cadences of an orator.
According to our interpretation, instinctive imitation is a factor of wide importance in animal behaviour, intelligent imitation, arising in close connection with interest in the doings of others, is a co-operating factor, but of intentional and reflective imitation there is at present no satisfactory evidence in any animal below man.
The foundations of intercommunication, like those of imitation, are laid in certain instinctive modes of response, which are stimulated by the acts of other animals of the same social group. These have been fostered by natural selection as a means of social linkage furthering the preservation, both of the individual and of the group.