130 Studies in Animal Behavior 



frog have yielded similar indications of slow learn- 

 ing. In some respects such learning resembles the 

 slow formation of a habit rather than the judgment 

 of a consciousness which "sizes up" the situation and 

 determines upon a certain course of action. It is 

 quite probable that such a primitive form of learn- 

 ing does not include any association of ideas. It 

 can be satisfactorily accounted for by assuming noth- 

 ing more than an association of certain sense per- 

 ceptions with particular movements. The animal 

 may have no ideas to associate nothing but sense 

 impressions and motor impulses. Of course its men- 

 tal content may include much more than this, but in 

 interpreting the behavior of animals it is generally 

 advantageous to follow the principle laid down by 

 Lloyd Morgan which is a sort of special appli- 

 cation of the law of parsimony that we should not 

 assume the existence of a higher psychic function 

 if the phenomena can be explained as well in terms 

 of a lower one. 



The step from sensori-motor association to the as- 

 sociation of ideas is not, I believe, a wide one, and 

 comes about as a natural consequence of the elabo- 

 rateness and what Hobhouse has designated as the 

 "articulateness" of the mental process of adjustment. 

 It is foreign to our purpose, however, to trace the 

 increase in the number, delicacy, quickness and com- 

 plexity of the processes of association which we meet 

 in the various stages of mental evolution. Our prob- 

 lem at present lies in the initial step involved in the 



