CHAPTER III 



THE INSTINCTIVE REACTIONS OF YOUNG CHICKS l 



THE data to be presented in this article were obtained in 

 the course of a series of experiments conducted in connec- 

 tion with the psychological laboratory of Harvard Univer- 

 sity during the year 1896-1897. About sixty chicks were 

 used as subjects. In general their experiences were entirely 

 under my control from birth. Where this was not true, the 

 conditions of their life previous to the experiments were 

 known, and were such as would have had no influence in 

 determining the quality of their reactions in the particular 

 experiments to which they were subjected. It is not worth 

 while to recount the means taken so to regulate the chick's 

 environment that his experience along certain lines should 

 be in its entirety known to the observer and that conse- 

 quently his inherited abilities could be surely differentiated. 

 The nature of the experiments will, in most cases, be such 

 that little suspicion of the influence of education by ex- 

 perience will be possible. In the other cases I will mention 

 the particular means then taken to prevent such influence. 



Some of my first experiments were on color vision in 

 chicks from 18 to 30 hours old, just old enough to move 

 about readily and to be hungry. On backgrounds of white 

 and black cardboard were pasted pieces of colored paper 

 about 2 mm. square. On each background there were six 



1 This chapter appeared originally in the Psychological Review, Vol. VI, 

 No. 3. 



