618 THE BIOLOGICAL BASIS OF INDIVIDUALITY 



without the existence of situations which would give it a functional sig- 

 nificance in the natural or social struggle. This type of behavior is sought 

 for its own sake, for the satisfaction which the instinctive action provides, 

 dissociated from the results to which it would lead if used in the struggle of 

 life. Also, the modifiable modes of behavior, those based on memories or 

 representing conditioned reflexes, are built on the foundation of simple 

 reflexes and instincts ; they are an elaboration of these processes. As a 

 result of this extension in the range of behavior, the environment, as far as 

 space, time and the relations to other organisms are concerned, has become 

 larger ; the differentiation between individuals has become finer. 



However, the reflex and instinctive basis of behavior remains and the 

 response to sense impressions on this primary basis takes place with less 

 delay than when there is an interference by the restraining effects of thought ; 

 however, memories of frustrations and pain may inhibit reflex and instinc- 

 tive actions also in less differentiated mammals. Complex processes, such as 

 the building of a nest for the young, which in more primitive animals are 

 purely instinctive, not directed by modifiable thinking, are largely reflex 

 actions also in mammals. Many years ago the writer followed with interest 

 the nest-making activities of mother rats, which seemingly indicated the 

 presence of intelligence and thought. When this nest-making instinct is 

 active, the mother may be seen running around in the cage carrying every 

 little article that can be used for nest-making to the place where the nest 

 is to be. But if the observer thgn transfers the rat from the netwire cage to the 

 outside of the cage and allows her to run around it, the instinct to gather 

 material for the nest continues to be active and she now pulls things away 

 from the nest as soon as she reaches it from the outside of the cage, just as 

 readily as she formerly had carried things towards the nest. Returned to the 

 cage, she now again carries back to the nest the things she had taken away 

 from it. No reasoning can be detected in these actions. 



While thus, on the whole, the life of higher mammals is still rigid and 

 fixed, nevertheless the plasticity of individual and social activities has become 

 greater than it was in the more primitive organisms. Similarly, the activities 

 of dogs are not essentially creative, in the sense that the constituents of a 

 composite experience would first be taken apart and then synthesized in a 

 new fashion. For instance, a dog looking for a ball which has been thrown 

 into a basket, attempts, in accordance with inherited reflexes, to recover it 

 by scratching the basket with his feet and pushing it along with his nose, 

 without succeeding in obtaining the ball by these means ; he does not discover 

 the simple expedient of turning the basket over, and if the basket is turned 

 over by accident, the dog does not readily make use of this experience. A 

 higher stage has been reached in anthropoid apes. The chimpanzee is able to 

 invent new modes of action, to compare new combinations by shifting of 

 mental elements, and thus to accomplish a certain end by means which are 

 not directly of an instinctive character. In this manner the unpredictability of 

 behavior, or what appears as freedom of action, is increased ; this increase how- 

 ever, is very limited, and is closely related to the unconditioned reflexes and 



