HABIT FORMATION IN THE ALBINO RAT 15 



This rapid decrease in time and distance at the beginning 

 of the problem was characteristic of all groups, and is clearly 

 shown in the initial drop in all the curves. 



TWENTY-FIVE DAY RATS 



Work on this group began at twenty-five days when the 

 rats were so small that they could crawl through the mesh top 

 of the maze, and could touch the sides of the alleys only by 

 running from side to side, while other rats could remain in 

 the center of the path and touch both walls of the runways 

 with their vibrissae. These rats were weaned at eighteen days, 

 and were fed in the maze for five days preceding the experiment, 

 the forty-five and thirty minute feeding periods being omitted. 

 For the first day or two after starting the problem, they were 

 allowed to eat for six or seven minutes instead of five minutes 

 at the end of each day's work, since it developed that a shorter 

 ration had a weakening effect on animals so young. The little 

 rats were exceedingly active, and on entering the maze ran 

 so rapidly that it was very difficult, but never impossible, to 

 trace their movements. For the most part they showed great 

 eagerness to escape from the starting box, some even acquiring 

 the habit of lifting the door partway with the nose, and as a 

 rule they had no hesitancy in entering unexplored portions of 

 the maze, in this respect differing from most of the rats in this 

 experiment. The error of circling the food box occurred more 

 often with rats of this group than with those of any other, the 

 explanation being, perhaps, that in their over-eagerness to reach 

 the food they acquired such momentum than they ran past 

 the entrance to the food box. 



