278 The Animal Mind 



ments where, after rats had learned a maze, the path was 

 altered, certain passages being closed and others opened. 

 The rats found it decidedly harder to learn to enter former 

 cul-de-sacs than to take those turnings which they had 

 formerly omitted merely because they were a longer way 

 around than the true path. The positively unpleasant 

 experience of running into a cul-de-sac had more com- 

 pletely eliminated the movements that led to it than did 

 the merely useless running of a longer passage. Finally, 

 it is clear that we cannot draw a hard and fast line between 

 a useless reaction and a harmful one. We have seen that 

 a severe punishment like an electric shock may delay learn- 

 ing because it attaches itself to the learning situation as 

 a whole. And in the writer's experiments "with rabbits 

 (756), a young rabbit of very nervous temperament was 

 rendered unfit for further experimentation simply by hap- 

 pening to push repeatedly at the wrong or closed door of 

 a box. He had been working well up to that time, but from 

 that time on he ran away whenever he was confronted with 

 the experiment box. It would appear that emotional 

 factors in the animal may render movements positively 

 harmful which would ordinarily be merely useless. 



75. The Formation of Systems of Successive Movements 



We have now to consider another type of learning, dia- 

 metrically opposed to that of the dropping off of movements. 

 In this type, the movements which an animal makes suc- 

 cessively become organized into a series. No movement of 

 the series is dropped out as a result of the learning, but the 

 oftener the series is run through, the more rapidly it is 

 performed. It is evident, if we consider our own learning 

 processes, that many of them are of this type. When we 



