THE WHITE RAT AND THE MAZE PROBLEM 23 



side. In this side there is the possibility of an error, but not 

 one into which the animal runs headlong. Hence from the 

 very first there is a safe experience of a definite sensory sort 

 which extends over a considerable period of time. Because it 

 is the first experience, because it proves safe, because the ani- 

 mal, on the whole, is more in this path than the other, because 

 his returns are made on this path, these may be some of the 

 reasons why this path proved more potent, more dominant, 

 more directive than the other and indicate one way in which 

 learning may possibly begin. 



The term learning needs 'more careful definition. Certainly 

 there was little evidence of discriminative learning here. If 

 there was any, it must have occurred chiefly within the first 

 trial. This possibility may be referred to in a later paper. The 

 curve showing the rate of elimination of time and errors furnishes 

 a slight indication of learning to use vision in the interval between 

 the fifth and the tenth trials, Fig. 7. 



If the mere strength of the visual stimulus was the effective 

 cause of the reinforcement or modification of the usual controls, 

 then we shall have to conclude that the white path was, on 

 the whole, the more dominant one. The entire matter then 

 would hang upon the supposition that the brightness factor in 

 a certain path had the power to hold or compel the attention 

 of the animal. 



The time taken per trial depends of course upon the speed 

 and the accuracy. The more errors an animal makes, the more 

 blind alleys he explores, the longer the time per trial. Thus 

 the fewer errors would largely account for the lessened initial 

 time. The contrast between black and white, as will be re- 

 membered, was as strong as could be produced. The final 

 inaccuracies might have been due to this contrast effect which 

 persisted to the end and attracted the attention of the rats 

 when they were momentarily distracted and thus led them into 

 errors. The stimulating power of this contrast was no doubt 

 responsible for the late development of the kinaesthetic con- 

 trol. But the slow change, when it did come, from reliance 

 upon vision to the automatism of kinaesthesis left vision free 

 to be caught, to be attracted by these contrasts, and led the 

 animals into errors. 



The decrease of final speed might have been due to the greater 



