Considerations on the Problem of Learning 153 



by aggressive, outreaching movements, and to in- 

 jurious stimuli by movements of withdrawal, retreat 

 and avoidance. All these are matters of pure in- 

 stinct. Given the power of forming associations 

 between responses, the animal acquires new habits 

 of action by repeating those responses which arouse 

 instinctive acts of a congruous kind, and by dis- 

 continuing those responses which arouse instinctive 

 acts of an incongruous kind. Modifications of be- 

 havior brought about in this way would, in general, 

 effect a closer and more adequate adjustment of the 

 organism to the stimuli that act upon it. The asso- 

 ciations formed would be in the direction of re- 

 fining the creature's instincts and adapting them to 

 varied conditions of life. Intelligence so developed 

 would be quite generally subservient to instinct, as 

 in fact we find it to be, especially in its more rudi- 

 mentary stages of development. The new things 

 an animal learns to do are done because they have 

 been assimilated to its instinctive activities. 



The interpretation of learning which we have 

 been considering ascribes an important role to re- 

 inforcement and inhibition. The essential nature of 

 these processes, despite much investigation and 

 speculation on the part of physiologists, still re- 

 mains an enigma. If we thoroughly understood 

 their nature and knew something more of the 

 changes (whether in the synapses or elsewhere) by 

 which associations are established, we should doubt- 

 less be able to penetrate more deeply into the mech- 



