Let us now turn our attention to the outcome of the experimental method as applied to higher forms, such as clogs, cats, rats, and chicks. In general, the animals are confined in cages, while appeal is made to their intelligence, ingenuity, and memory through the avenue of longer. The results have been such as considerably to decrease our estimate of the mental capacity of the ani mals. Thus Tho•ndike, after tracing the forma tion of associations in the animal consciousness, remarks that his work "has rejected reason, comparison or inference, perception of similarity, and imitation. It has denied the existence in animal consciousness of any important stock of free ideas or impulses, and so has denied that animal association is homologous with the asso ciation of human psychology." A vigorous pro test against this mode of interpretation has, it is true, been entered by Mills, who contends that confinement in cages is essentially an artificial and abnormal condition, that hunger is not the strongest possible means of appeal to animal intelligence, and that "it seems more probable that the mental processes of the highest animals are not radically different from those of man, so far as they go. but that the human mind has capacities in the realms both of feeling and intellection to which animals cannot attain." The general trend of opinion is, apparently, for Thornlike and against Mills; but. in face of the divergence of expert judgments. the layman will do well to held himself in suspense. until such time as community of investigation has brought about a substantial agreement on time main points at issue. The recent. publication I Kline) of a laboratory course in comparative psychology is a hopeful sign.
To return to the main problem: we have to show how the reflex and, to all appearances, whollymmenseieus reactions of such forms asants and bees are to be squared with the evidence of mentality in the protozoa, evidence which makes mind coeval with life. It seems reasonable to
adopt the view which sees in impulse (the con sciousness accompanying action upon presenta tion; see ACTION) the original and primitive type of consciousness. Now, the impulse has varied in two directions. In the first place, by the grad nal effacement of its distinctively mental fea tures, the primitive type of action has come to take the form of the reflex, a relatively simple mechanical answer to stimulation. Here, in the light of Jennings's observations, we must place paramecium. In the second place, the impulsive action has, in certain forms of organic life, broadened out into selective and volitional action. Mentality has grown mare complex, as in the other direction it has died out. In this line of development stand the higher animals, including man. Lastly, the most developed forms of action exhibit a constant tendency to become automatic; so, e.g., piano playing, bicycle riding. In other words, there is a tendency for certain phases of complex psycho-physiological activity to degen erate into activity which is simply physiological. The final outcome is, therefore, the formation of a system of reflexes which, in view of their cir cuitous development. we may term secondary reflexes. Ants and bees, as they appear in Bethe's pages, would then he types in which practically every vestige of a once fairly compli cated mental structure has disappeared, to make way for an elaborate series of secondary reflexes. Thorndike has even argued, in similar vein, that the present anthropoid apes may be mentally degenerate: that their chattering is possibly "a relic of something like language," and not a first attempt at la Ilgllage-Making.