Yerkes, ModifiahiUty of Behavior 



239 



The habit whose formation was studied quantitatively, in the case 

 of groups of dancers consisting of five pairs each, for the ages of one 

 month, four months, seven months, and ten months, may be called 

 the white-black discrimination habit. It involved the discrimination 



Fig. 1. Fig. 2. 



Fig. 1. — Discrimination box. W, electric box with white cardboards ; B, 

 electric box with black cardboards. 



Fig. 2. — Ground plan of discrimination box. A, nest-l>ox ; B, entrance 

 chamber ; W W, electric boxes ; L. doorway of left electric box ; R, doorway 

 from right electric box to alley; O, swinging door l>etween alley and A; IC, 

 induction apparatus ; C, electric battery ; K, key in circuit. 



of the entrances to two boxes, one of which was white and the other 

 black, and the entering of the white box. Any attempt to enter the 

 black box was punished by an electric shock. 



Figures 1 and 2 show the experiment box in perspective and in 



