would agree, constitutes one and only one of the chief factors in this problem. The interpretation of our findings, stated in the previous sections, may be dealt with briefly here.
Let us consider the different kinds of imitation. Principal Morgan, that peerless thinker in the problems of Animal Behavior, has proposed the following:
(1) Mimicry, which lies below the level of imitation and which (the present writer would add) is determined by forces wholly outside the individual. Mimicry is determined for the individual in the previous history, or, let us say, experience of the species, either through environmental or organic conditions. Some recent investigations give promise of serious revision of our thought with reference to just why the walkingstick, for example, is so like the branch on which it is found. At any rate, it is the experience working through natural selections and other ways, and not at all necessarily through transmission of acquired characters, that pre-determines Mimicry in the individual. The reason for the writer's use of the word experience will appear later.
(2) Instictive Imitation. This is again inherited though now the emphasis, because of the meaning of the word "Instinctive," is on function rather than structure. Partly because it is function rather than structure, but also because of the nature of the external stimulus which sets the instinct going, it is to be expected that what the individual imitates instinctively will not be copied in so fixed a manner as mimicry demands. There will be a good deal of the individual in it. Nevertheless such instinctive imitation is done readily and automatically, and is determined by the experience of the species. It belongs in the same class with mimicry, but offers more of plasticity of action to the individual. They therefore have the same relation as Hobhouse has pointed out for Reflex Action and Instinct. Examples of instinctive imitation are to be found in the "following instinct," which is very well illustrated by the observations described on page 6. Many, if not all, of the instances of imitations of song in birds are examples of instinctive imitation. The calls and songs of birds are very intimately associated with the mating as well as other instincts. Some of these might well become intelligent after being performed the first few times.
(3) Intelligent Imitation. Until the appearance of his most recent work on Animal Behavior this formed the last and highest part of Morgan's classification. In this book, however, this author makes a distinction which the present writer deems most necessary and useful, but which needs to be carried further.
All other earlier writers separate too widely instinctive and
