32 INDIVIDUAL DIFFERENCES AND FAMILY RESEMBLANCES 



The distribution curves for the males and the females, for the 

 interference test of ten trials in the maze, are also given in Fig. 8. 

 Here it is to be seen that the curve for the males is distinctly skewed. 

 Seventeen males are grouped between and 20 seconds; eight be- 

 tween 20 and 40 seconds, and from there on the curve is similar to 

 the one made by the same animals in the initial learning period of 

 the maze test, but in the present case no males are to be found that 

 took, on the average, longer than 200 seconds to complete the test. 

 This figure shows that the mode for the females is to the right of the 

 mode for the males; the greatest number of females, namely nine, 

 are to be found between 40 and 60 seconds. The curve for the fe- 

 males is irregular, again showing a superiority in favor of the males, 

 while here two females failed to learn the test. 



The distribution curves of both sexes for the retention test show 

 that the curve for the males is similar to the one above that we have 

 just examined. It is skewed, with the mode between and 20 sec- 

 onds, where twenty-one animals are to be found, while no records for 

 the males exceed 160 seconds. The curve for the females is less 

 skewed than that of the males; an equal number of individuals, 

 namely nine, are to be found between and 20 seconds, and 20 and 

 40 seconds ; the curve then drops quickly, but rises again in the re- 

 gion between 60 and 80 seconds, where there are six animals. Then 

 the curve for the females gradually falls, but again shows the same 

 characteristic that is to be found in all the comparative distributions, 

 namely, that a number of females are distributed beyond the max- 

 imum records made by the males in the same test. In this case five 

 females made longer average time records than the males, and two 

 of them failed to learn the test. 



The distribution curves for the males and females in the multiple 

 choice test are given at the bottom of Fig. 8. Here the mode for both 

 sexes is to be found between and 20 seconds ; but the curve for the 

 males is steeper than the corresponding one for the females; twenty 

 males being found between and 20 seconds ; seven between 20 and 

 40 seconds ; five between 40 and 60 seconds, and finally two between 

 80 and 100 seconds, which is the maximum time record for the males. 

 The distribution curve for the females shows eleven individuals be- 

 tween and 20 seconds, and then, as shown in the figure, the curve 

 drops at a regular rate ; there being nine individuals in the next time 

 group, seven in the next, four in the next, and two in the next, where 

 the curves for both sexes meet. It is to be noted, however, that the 

 same thing occurs here that was found in the three previous distribu- 

 tions, namely, that the females exceeded the maximum time records 



