244 Animal Intelligence 



dividing line, since there is no clear gap between those 

 activities which naturalists have come to call behavior and 

 the others. 



The discussion will include : First, a description of two 

 laws of learning ; second, an argument to prove that no ad- 

 ditional forces are needed that these two laws explain all 

 learning ; and third, an investigation of whether these two 

 laws are reducible to more fundamental laws. I shall also 

 note briefly the consequences of the acceptance of these laws 

 in one sample case, that of the study of mental evolution. 



PROVISIONAL LAWS OF ACQUIRED BEHAVIOR OR 



LEARNING 



The Law of Effect is that : Of several responses made to 

 the same situation, those which are accompanied or closely 

 followed by satisfaction to the animal will, other things being 

 equal, be more firmly connected with the situation, so that, 

 when it recurs, they will be more likely to recur ; those which 

 are accompanied or closely followed by discomfort to the ani- 

 mal will, other things being equal, have their connections with 

 that situation weakened, so that, when it recurs, they will be 

 less likely to occur. The greater the satisfaction or discomfort, 

 the greater the strengthening or weakening of the bond. 



The Law of Exercise is that : Any response to a situation 

 will, other things being equal, be more strongly connected with 

 the situation in proportion to the number of times it has been 

 connected with that situation and to the average vigor and dura- 

 tion of the connections. 



These two laws stand out clearly in every series of ex- 

 periments on animal learning and in the entire history of the 

 management of human affairs. They give an account of 

 learning that is satisfactory over a wide range of experience, 



