THE FORMATION OF HABITS AT HIGH SPEED 



181 



SIGHT 



The experiments on sight bear simply on such rays as we our- 

 selves are able to perceive, and were performed in a carefully 

 constructed and thoroughly efficient photographic dark room. 

 From the subjective standpoint, the animals were allowed to 

 swim in the dark, but whether what we call dark is in reality 

 dark to a rat, is another question. 



Two sets of animals were used, two adults, and two young- 

 ones less than a year old. Each animal was given four sets of 

 six trials. The averages follow: 



If the first two series of A are compared with the last two, 

 it will be found that this animal remained practically constant 

 in speed; if a similar comparison be made for B, we find that 

 this individual increased its speed on the average by 9.28"; 

 whereas the records of a and b show increases in efficiency in each 

 of the last three sets. Undoubtedly, then, the tank problem can 



THE JCURNAL OF COMPARATIVE NEUROLOGY AND PSYCHOLOGY, VOL. 20. NO. ,?. 



