INSTINCTS AND HABITS IN CHICKS 



49 



are described only by reference to the catalogue name or num- 

 ber of the papers. Measurement of tint (or brightness) was 

 attempted in only a few special cases. The purpose of these 

 experiments at their inception was not to investigate the color 

 reception of chicks, but to test modification of behavior. How- 

 ever, the reactions to reflected colored light proved so interesting 

 that a slight digression from the central interest of the research 

 was later made in the effort to gather some new facts in this 

 closely related field. 



Chicks were tried first with Bradley black and white. Most 

 of the first tests involved many elements of irregularity. In 

 some the right and left exchanges of cards were not balanced 

 in the series. In others, chicks had been shocked too severely 

 and either hesitated about entering the electric boxes or balked 

 completely. Again, work was carried over from the preliminary 

 to the new apparatus. The best of these first results are pre- 

 sented below. Chick no. 7, after being given preference trials 

 which were of questionable value, was regularly trained to 

 avoid white and go to black.' 



TABLE 8 

 Black- White Reactions 

 Chick no. 7. Hatched 12/10, '07. Sex, F.^ 

 Series^ Date Right Wrong 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



15 : 



16 



' In all the tables of results in discrimination work the stimulus to which a chick 

 was forming the habit of positive reaction is each time mentioned first. It is to 

 be assumed that the animals were without previous training unless a definite state- 

 ment to tlie contrary is made. 



^ All sex determinations were made by dissection. 



^ In some of the preliminary work the regular 10-trial series was doubled. 



