248 J. E. DE CAMP 



Six white rats were used, four males and two females. 



Rat 1 : Male, about six months of age 

 Rat 2: Female, about six months of age 

 Rat 3 : Male, about two months of age 

 Rat 4 : Male, about two months of age 

 Rat 5 : Female, about two months of age 

 Rat 6: Male, about two months of age 



The following explanation holds for all tables. Under "days" 

 (first column) is given the number of experimental days required 

 for the animal to adjust itself to the shorter path, i.e., until the 

 rat was clearly taking (preferring) the shorter path. Under S 

 and L (second and third columns) appears the absolute number 

 of times in the given experimental days the rat took the shorter 

 (under S) and longer (under L) paths. It may be pointed out 

 here that if the rat has come to find food on the right side, for 

 example, and has established a habit of going in that direction, 

 the sudden shift of the food by the experimenter to the opposite 

 side (left in our example) is not followed immediately by a 

 tendency to go in the opposite direction, but the old direction is 

 taken at first and then less and less often, with increasing number 

 of trials, until the number of times he takes the new direction 

 during the day's experiment begins to exceed the tunes he takes 

 the old. Obviously this shows adjustment, and to indicate it 

 S need not be greater than L, but the experimenter usually con- 

 tinued the trials until adjustment was quite certain. Under 

 Dn (fourth column) is given the direction from H of the box 

 containing food (indicating the shorter path) for that particular 

 set of trials: R, right; L, left. Under R (fifth column) is 

 given the ratio of the length of the long to the length of the short 

 path. Now if 



P t = total length of path 

 P. = length of short path 

 Pi = length of long path 



D = absolute difference between long and short paths 

 R = ratio of length of long (Pi) to length of short (P.) 

 path 



