BEGINNINGS OF INTELLIGENCE 167 



is placed outside, the animal will probably make vigorous 

 efforts to escape by clawing and biting in various parts of 

 the enclosure, which are the usual instinctive methods em- 

 ployed in similar situations. If the right movement is hit 

 upon and the cat gets out and secures food, it will probably 

 make its escape more readily than before when placed hi 

 the box a second time. After a number of trials the cat 

 will come to make the right movements for escaping very 

 soon after being placed in the box and its useless random 

 movements will be discontinued. The connection between 

 the perception of the mechanism of escape in the box and 

 the act necessary to gain its liberty comes to be more and 

 more firmly established in the cat's brain with repeated 

 experiences. The cat perceives a number of things in the 

 box and performs a number of different acts, but out of 

 all these, associations are formed only between certain 

 stimuli and those responses to them which bring pleasure 

 to the animal. 



Pleasure and pain have apparently a fundamental con- 

 nection with the development of intelligent responses out 

 of instinctive activity. Were there not something to clinch 

 or strengthen the connection between certain stimuli and 

 the appropriate responses to them the organism might per- 

 form random movements till doomsday without being a 

 whit better off. It is a problem therefore of fundamental 

 importance to ascertain in what the mechanism of this 

 ability to profit by experience essentially consists. It is 

 not mere habit, not the mere making more permeable certain 

 preformed connections in the brain. One act would then be 

 just as apt to be followed up as another. Whether an act 

 tends to be followed or not depends on what it brings to the 

 organism. Apparently we have to do with a selective 



