276 The Animal Mind 



obtaining of food. Rubber t (346) does not find that this 

 is actually the case, but Vincent (750) does, and on the 

 whole the evidence points to the conclusion that the errors 

 nearest the final success are the first ones eliminated. 

 Such exceptions to this tendency as appear may well be 

 due to two causes : first, the natural tendency of useless 

 movements to drop away even when a successful movement 

 is not pushing them out, and secondly, the equally natural 

 but wholly opposed tendency of movements to organize 

 themselves into systems, a tendency which will be con- 

 sidered in the next section. Watson (771) lays especial 

 stress on the fact that the successful movements in puzzle- 

 box and maze experiments have the advantage of fre- 

 quency of performance. The successful movements are 

 always performed, in every maze experiment, simply be- 

 cause the experiment continues until they are performed ; 

 there is no such necessity that any particular unsuccessful 

 movement should be performed in every experiment. Thus 

 the successful movements, Watson thinks, owe their survival 

 to the law of repetition. It is quite probable that their in- 

 evitable performance once in each running of the maze may 

 be a factor aiding their survival, although quite conceivably, 

 as Thorndike * has suggested, many unsuccessful movements 

 may actually be oftener performed, owing to the fact that 

 they may be repeatedly tried in the same experiment. 

 But Watson endeavors to reduce all learning through the 

 dropping off of movements to the influence of the frequency 

 with which the successful movements occur ; and this can 

 only be done by ignoring such cases of learning as those 

 where the frog ceased in one or two trials to snap at food 

 when the snapping led to harmful consequences, or where 

 the spider learned not to disturb itself at the sound of a 



1 Jour. Animal Behav., vol. 5 (1915), p. 465. 



