§ 1. Introductory. — Imitation is a process of very great importance for the development of mental life in both men and animals. In its more complex forms, it presupposes trains of ideas; but in its essential features it is present and operative at the perceptual level. It is largely through imitation that the results of the experience of one generation are transmitted to the next, so as to form the basis for further development. Where trains of ideas play a relatively unimportant part, as in the case of animals, imitation may be said to be the sole form of social tradition. In the case of human beings, the thought of past generations is embodied in language, institutions, machinery, and the like. This distinctively human tradition presupposes trains of ideas in past generations, which so mould the environment of a new generation, that in apprehending and adapting itself to this environment it must rethink the old trains of thought. Tradition of this kind is not found in animal life, because the animal mind does not proceed by way of trains of ideas. None the less, the more intelligent animals depend largely on tradition. This tradition consists essentially in imitation by the young of the actions of their parents, or of other members of the community in which they are born. The same directly imitative process, though it is very far from forming the whole of social tradition in human beings, forms a very important part of it.