itj'^ to learn. 



Yerkea-^ raised the question of the relation of age to 

 habit formation in the dancing mouse. Ee worked first on the 

 acqi:isition of the v;hite-black disorimination hubit, and later 

 on the learning of simple labyrinth pathways. The indices of 

 modif iabiliti as given by the number of training tests requir- 

 ed to complete the habit for dancers of one and four months 

 respectively, show that the males learned the -.vl.ite -black dis- 

 crimination habit more quickly at one month (30 days) than at 

 four months (120 days) while the reverse was true of the fe- 

 males. The female was superior to the male, however, in the 

 formation of the labyrinth habit. In later work he finds 

 that male dancers ten months old learn the labyrinth more rapid- 

 ly than those one to two months old, while there is practical- 

 ly no difference in rapidity of learning of one to two month 

 and ten month females. The old dancers are somewhat suj,erior 

 to the young in their ability to learn the labyrinth paths. 

 With regard to the sensory habit he says: 



"1. The dancer at one month of age acquires a particular 

 white-blac]; visual discrimination habit more rapidly than do 

 older in'\ividuals. Prom the first until the seventh month there 



1. Yerkes, R.i:., The Dancing Mouse , The :acmillan Co., Ii07. 

 Z, Loc. cit. p. 2 74. 

 5. Log. cit. i . 275. 



4. Yerkes, R.I.:., L^odif icability of Behavior in its relation to 

 the Age and Sex of the Dancin.- House, Journ. Comp. rieurol. 

 and Psychol. 19, (150&) 257-2 71. 



5. loc. cit. pp. 266-267. 



