64 DEVELOPMENT AND PURPOSE CHAP. 



How it operates may be best considered in relation to a 

 somewhat different case. 



() Assimilation. 



In acquiring skill we perfect the means to an end which 

 is already determined. In the cases now to be considered 

 the end itself is affected. More accurately we learn to re- 

 direct our action, to quell a response to which we were 

 originally impelled or to meet with a definite reaction some 

 stimulus to which we were originally indifferent. 



Learning of this kind plays an important part among 

 animals as well as among men. It is seen in its simplest 

 form where two sensory data, as A and B, are closely related 

 in time and where one of them is charged with feeling. 

 The relation is particularly clear and simple in its operation 

 where the first datum A is a stimulus setting a hereditary 

 mechanism to work, which has B as its immediate result. 

 Thus, in a familiar observation of Mr. Lloyd Morgan, a 

 chick sees a small bit of orange peel on the ground (A). 

 It pecks at it, and experiences a taste (B) which is appar- 

 ently unpleasant ; for the peel is dropped, and thereafter, 

 or perhaps after one or two more experiments, orange peel 

 is avoided. The pecking impulse is in relation to these 

 objects inhibited. Now, in speaking of an * unpleasant 

 taste ' we are inferring from our own consciousness a feel- 

 ing in the chick which it may be difficult to verify. But 

 we are not concerned for the moment with the inner char- 

 acter of the process by which correlation is effected in any 

 particular species of animal. It is certain that among our- 

 selves an experienced feeling 1 is the operative element in 

 cases of the kind, and in accordance with the principle laid 

 down above, in describing animal behaviour we use terms 

 involving such consciousness and such only as would be 

 essential with the parallel case among men. In the human 

 mind much higher factors may at any time co-operate, even 

 in the simplest act, while we may have sufficient evidence 

 for denying these factors to the animal. In such a case the 



1 Meaning by the term here and throughout this discussion the entire 

 psycho-physical process in which feeling is involved. The inherent 

 causal efficacy of the psychical is not assumed. 



