SIZE AND FORM PERCEPTION 85 



9. ro = Partial turn around, right to left; tz>, left to right. 



10. \\ = Position directly before division between each compartment; by turning 



head either stimulus area is visible. 



11. „ = Escape to nest box. 



12. E = Error in choosing; this is followed by time in seconds. 



13. 0= Correct choice; this is followed by time in seconds. 



The preliminary series were begun during the second week, 

 usually when the chicks were io days old. The experiments 

 were always conducted during the forenoon between the hours 

 of eight and twelve. I believe the best results would be obtained 

 from chicks if the work were begun earlier than eight. Chickens 

 naturally start out early in the morning for their food. That 

 is the time when they are most active. My observations do 

 not wholly agree with Breed's conclusion that "hunger did not 

 play a more important part than the reaction to confinement 

 and solitude." 8 My best results came when I took the chick 

 early in the morning and allowed it to earn its breakfast. The 

 chick from which I received the best results reached the stage 

 where it apparently took pleasure in the experiments. When 

 I placed it in the apparatus it regularly began to give the char- 

 acteristic "food twitter." This twittering was continued all of 

 the time the bird was choosing and after it had escaped to the 

 nest box where I was careful always to have a little food. 



In the matter of rewarding with food, however, great care 

 is necessary. A three-weeks-old chick will "fill up" in a very 

 short time and then experimental work is difficult. I was care- 

 ful to have only a few grains scattered in the litter of the nest 

 boxes so that the chick had to work to find them. After getting 

 this plan somewhat perfected I found that a chick could be 

 given as high as 50 trials with no more difficulty than was pre- 

 viously common in 20 trials. 



Until the chicks were five or six weeks old it was found best 

 to give them no more than one series daily. After they reached 

 this age the number of tests could be increased without harm- 

 ful results. The subjects had usually learned to solve their 

 problems by this time so that they expended much less energy 

 than they did during the earlier tests. Moreover, the experi- 

 menter had an opportunity to select from his group the most 

 promising subjects to which he could devote more time. 



Behavior Monographs, vol. 1, no. 1, S. N. 1, p. 47. 



