THE ASSOCIATIVE PROCESSES IN ANIMALS. 85 



The Peckhams' study of the solitary wasps convinced them 

 that these insects were gifted with associative powers as well 

 as instincts. If we begin at the extreme end, with the Pro- 

 tozoa, that is, we find diverse opinion's ; but the most recent 

 and by far the most thorough observer, Dr. H. S. Jennings, 

 finds absolutely no signs of any capability to modify reactions 

 in accord with the pleasurable or painful results they bring. 

 At the other end of the scale, in man, associative processes of 

 the animal sort are surely present, though in the adult they 

 are often overgrown and interpenetrated by the ideational life 

 to such an extent as to require, so to speak, careful dissection 

 to make them demonstrable. The human infant, however, 

 learns to cry to obtain certain favors, to go to certain places 

 for certain things, and, up to a certain age, to react to certain 

 words, -in just the same way that the animals learn. And in 

 learning certain sorts of novel accomplishments, e.g., to play 

 billiards or tennis, the adult uses to a large extent this same 

 trial-and-error method, progressing because satisfaction stamps 

 in the particular movement or stroke which caused it and 

 makes the player, the next time the same situation appears, 

 more likely to make it. It may be that this is really the basal 

 fact in human intelligence, and that out of it are developed all 

 the higher' processes which are, in adult life, so ubiquitous that 

 the ordinary psychological treatise has nothing to say about this 

 simpler sort. Surely the infant, for about nine months, seems 

 to learn in no other way than the animals do. A completer 

 comparative psychology will, let us hope, one day tell us, among 

 other things, when and how this method of learning arose 

 among animals, and how much of a part it has played in the 

 development of the human mind. 



Delicacy, Complexity, Number, and Permanence of Associations. 



Granted that an animal possesses this associative power, 

 question arises as to the degree of delicacy and complexity 

 which the associations may reach, and as to the number of 

 such associations the individual can acquire and the length 

 of time they last. By delicacy we mean the animal's power of 



