Habit Formation : Discrimination Method 231 



ences which these experiments revealed and examine the 

 significant features of the general averages, and of the white- 

 black discrimination curve (Figure 29). 



The preference series, A and B, reveal a constant tendency 

 to choose the black box, whose strength as compared with 



A B 1 8 3 4 5 6 1 7 8, 9 10 U 12 '13 14 



FIGURE 29. Error curve plotted from the data given by twenty dancers in white- 

 black discrimination tests. The figures in the left margin indicate the number of 

 errors ; those below the base line, the number of the series. A and B designate the 

 preference series. 



the tendency to choose the white box is as 5.8 is to 4.2. In 

 other words, the dancer on the average chooses the black 

 box almost six times in ten. The first series of training 

 tests reduced this preference for black to zero, and succeeding 

 series brought about a rapid and fairly regular decrease in 

 the number of errors, until, in the thirteenth series, the white 

 was chosen every time. Since I arbitrarily define a perfect 

 habit of discrimination as the ability to choose the right box 

 in three successive series of ten tests each, the tests ended 

 with the fifteenth series. 



The discrimination curve, Figure 29, is a graphic represen- 

 tation of the general averages of Table 41. It is an error 

 curve, therefore. Starting at 5.85 for the first preliminary 



