THE FORMATION OF HABITS AT HIGH SPEED 179 



improved as much as the adults in former experiments, but this 

 may have been because they were unusually slow. If a conclu- 

 sion may be hazarded, it is that the additional stimuli had no 

 effect or perhaps a slightly depressing one, though this is un- 

 certain. 



The young, on the other hand, improved on the average 62.5 

 per cent, as compared with an earlier record of 53 per cent. Ani- 

 mals cc and dd have been eliminated from these calculations on 

 the ground of over-excitedness. The results might have been 

 expected. There was an unmistakable effect on the young, and 

 in two cases the additional discomforts and rewards produced 

 so much activity, that these particular records were vitiated by it. 



THE SENSES AND THE HABIT 



The relation between the senses and the acquisition of habits in 

 the white rat has been so thorough^ worked over by Watson ('07) 

 that I have performed only a few experiments, the results of which 

 I shall present for two reasons, first because they are corrobora- 

 tive, in spite of the differences in method; secondly, because they 

 show that the various senses can be eliminated without resorting 

 to the extirpation, or destruction of the sense organs. Under 

 the conditions of the experiments, hearing, smell, sight, and 

 touch, either singly or in any combination, may conceivably 

 furnish the sensual basis on which the habit rests. 



HEARING 



As the associations were formed while one of the four exits was 

 open, it may have been that the movements of the animals were 

 influenced by the differences in sound intensity or quality due 

 to the unblocked passage. Such differences, if they exist, 

 must be very small, for the closed openings are blocked simply 

 by wire netting, but as rats are known to perceive minute sound 

 differences, the point was well worth testing. 



Associations were established in the usual way, after which 



