104 FLETCHER, COWAN AND ARLITT 



left untampered with, ten were merely pierced with the dis- 

 secting needle and sealed, twenty-five were injected with five 

 drops of distilled water in place of the alcohol, and twenty-five 

 were injected with alcohol as usual. The incubator was always 

 divided into compartments which prevented the chicks from the 

 different groups of eggs from mixing as they hatched. As the 

 chicks were taken from the incubator they were marked with 

 pigeon markers having numbers on them and from that time 

 on were kept together and treated in exactly the same way 

 except in the case of a few which were isolated as a check on 

 the imitation factor. For purposes of convenience the chicks 

 which were hatched from normal eggs will be designated " nor- 

 mal;" those hatched from alcoholized eggs will be designated 

 " alcohol;" those hatched from eggs with distilled water in 

 them will be designated " water;" and those hatched from eggs 

 with holes in them will be designated " holes." 



In observing the behavior of the chicks their reactions were 

 divided into two groups, inherited and acquired. The inherited 

 reactions studied were, reactions to light, pecking and drinking 

 reactions, and reactions to height. The acquired reactions were 

 those involved in choice between two visual stimuli presented 

 by means of the Yerkes apparatus, as modified by Breed, 1 and 

 those involved in learning to run mazes. Promptness and direc- 

 tion of response to light, speed and accuracy of the pecking 

 and drinking reactions, and the height from which a chick 

 would jump were used as criteria of the types of behavior of 

 the first group. The number of trials necessary before making 

 ten correct choices and the time spent in the mazes were criteria 

 of the second group of reactions. 



The instinctive reactions of alcohol chicks differed little, if 

 at all, from those of normal chicks except in the case of reac- 

 tions to height. After the fifteenth day the alcohol chicks 

 jumped from greater heights than did the normal. Alcohol 

 chicks were, as a group, slower in reacting within the mazes 

 and had to be given more trials before they made ten correct 

 choices in the Yerkes apparatus. The water chicks and the 

 hole chicks were tested only for pecking reactions and mazes. 

 Their behavior resembled much more nearlv that of the alcohol 



1 Breed, F. S. The Development of Certain Instincts and Habits in Chicks. 

 Behav. Mono?,., vol. 1, no. 1, 1911. 



