BASIS OF THE PROBLEM 49 



learns in fact in some degree to operate the catch and thus to 

 gain freedom and food. The question which arises is what degree 

 of mental development we have to assume in order to account 

 for these facts. 



The stage in learning from experience which follows next 

 upon that present among some protozoa is exemplified by the 

 chick which at first instinctively pecks at various objects. If 

 it pecks at a yellow caterpillar with an unpleasant taste it will 

 drop it. The next time, or after a series of such experiences, it 

 will avoid the caterpillar. The explanation seems to be that 

 a modified response arises directly from the sight of the caterpillar. 

 The sense-impression has become charged with feeling that first 

 arose as the result of experience. This simple explanation is 

 to be preferred to that which would assume the realization by 

 the chick of the relation between the position when it again finds 

 itself with a yellow caterpillar before it and the nastiness which 

 it previously experienced. The process is thus one of the revival 

 of acquired meaning, and we have now to ask if a higher stage of 

 mental process is ever to be attributed to animals or whether the 

 behaviour of the animal in the cage is to be explained on the 

 same lines as the behaviour of the chick. 



' Let us suppose ', says Professor Hobhouse, ' revival to operate 

 in a mind capable of perceiving three objects A B C in definite 

 space and time relations, C being something desirable, e. g. food. 

 If the three objects are present to the senses, the first two leading 

 up to the third (e. g. as intervening objects in space), conation 

 will be definitely directed to C via A and B. Let this have 

 happened and then let A alone be given. If the animal is hungry, 

 i. e. if there is a conational basis to go upon, A will, according to 

 the law of revival, excite a conation corresponding to the previous 

 one, but this was a conation definitely directed to B and C in 

 succession as things standing in a definite relation to A. The 

 animal then directs its efforts to a point where, in accordance with 

 the first experience, B and C should be. It looks for them, or if 

 B is some change which brings C about, sets itself to perform 

 B and so obtain C. Its action is directed to something not 

 given, and this appears to be the germ of a conation or practical 

 idea.' ^ It is thus possible that in the behaviour of the animal in 

 the box we may have to recognize the first step towards a higher 



* Hobhouse, loc. cit., p. 76. 

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