10 INDIVIDUAL DIFFERENCES AND FAMILY RESEMBLANCES 



colored mice then tested, several yellow ones made poor records. 

 These mice were mated, and they and their offspring compose a 

 group of 27 individuals, whose average time and error record is con- 



o SLO 60 100 



NuMber 05 



FIG. 3. Total Distribution Curves for Maze Test and Multiple Choice Test. 



siderably poorer than the normal for the entire population. 7 The 

 yellow group gave an average time of 83 P.E. 7.0 seconds, and an 

 average of 2.0 errors for the last 15 trials. The remaining group of 

 63 mice, mostly white, gave an average time of 27.5 P.E. 2 seconds 

 and .9 error per trial. The yellow mice were thus found to take, on 

 the average, at least three times as much time, and to make twice as 

 many errors as did the white mice. The distribution curves for the 

 white group is skewed, most of the individuals falling between and 

 20 seconds. The curve for the yellow family is nearly flat, there 

 being about the same number of individuals between and 20 sec- 

 onds, as between 60 and 80 seconds, and between 140 and 160 seconds. 



7 This group of 27 mice was composed (see Tables I, IV and VII) of Nos. 

 20 and 26, and their seven offspring; No. 27, the sister of No. 26; a litter of five 

 mice, Nos. 32, 33, 34, 36 and 37 and their ten offspring, and finally two unre- 

 lated yellow mice, Nos. 2 and 3, that were used at the beginning of the experi- 

 ment. The 63 remaining mice of the white group bring the total to 90. 



