INDIVIDUAL DIFFERENCES AND FAMILY EE- 

 SEMBLANCES IN ANIMAL BEHAVIOR 



HALSEY J. BAGG 

 Instructor nr Biology, New York University 



In experimental work on animal behavior, but little 

 attention has been paid to individual differences, and 

 practically none to family resemblances. 1 In studying the 

 inheritance of conduct in man, experimental methods can 

 not be used. Students of eugenics depend on observa- 

 tions difficult to verify. In the work here described an 

 attempt has been made to apply the methods of genetics 

 to the study of conduct. Such work was begun by Pro- 

 fessor J. McKeen Cattell some fifteen years ago, but the 

 results obtained by him and his students were not pub- 

 lished, and the problem has been given to me. 2 



The plan of the experiment is to measure individual 

 differences in behavior, to determine the extent to which 

 the animal which departs from the average in one direc- 

 tion will depart in others, to measure the resemblances in 

 families and in lines of descent, and to determine the 

 degree to which kinds of conduct can be established in 

 family lines by selection. It is evident that such a prob- 

 lem can be solved only by many years of work and with 

 the facilities of a research institution. In the present 

 paper there are described the individual differences and 

 family resemblances of 90 mice, as determined by the time 

 required to find their way through a maze. The same mice 

 have been tested in other ways, and further experiments 

 are now in progress with the F 5 and F 6 generations. 



i Basset has recently published an article on "Habit Formation in a 

 Strain of White Eats with Less than Normal Brain Weight." Behavior 

 Monograph Series, No. 9, 1914. Macdowell in Science for November, 12, 

 1915, gives a brief abstract of work on "Parental Alcoholism and Mental 

 Ability. A Comparative Study of Habit Formation in the White Rat. ' ' 



lumbia University, the results being used for a master's thesis. 



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