A STUDY OF THE BEHAVIOR OF THE PIG 193 



sible boxes. Let us suppose that the animal enters directly 

 box 3. Immediately the experimenter lowers the entrance door 

 and thus confines the animal in the small compartment as 

 punishment for an incorrect choice. At the expiration of one 

 minute, the entrance door is raised and the pig is allowed to 

 retreat from the box and make another choice. We may now 

 suppose that the animal, after passing in front of boxes 2 and 1, 

 returns to 1 and enters it. The experimenter immediately stops 

 his stop-watch, lowers the entrance door, and, since this box is 

 by definition the right one, he immediately raises the exit door 

 and rewards the animal for correct choice by allowing it to eat 

 for a few seconds. He then, either by speaking to the pig or by 

 touching it with a whip, induces it to pass from the box by way 

 of the passage, D, and the alley, R or E, back to the appro- 

 priate yard, S. 



Having reset the apparatus, the experimenter now gives the 

 other pig a trial with the same problem and either with the same 

 or with a different setting of the doors. 



As a rule, the animals were fed only in the trough of the 

 apparatus. They were almost always hungry, and although 

 sufficiently well fed to keep them growing and in excellent 

 health, they usually seemed fairly hungry at the end of a day's 

 work. In no case was it necessary, in order to induce them to 

 work steadily, to have them extremely hungry. 



The influence of visual and olfactory factors was to be ex- 

 pected, and at various points in the investigation, precautions 

 had to be taken against following. 



PRELIMINARY TRAINING 



On June 2nd the pigs were brought to the Field Station and 

 placed in the shelter yard, and in the afternoon of the same 

 day, they were fed in the trough of the apparatus, all of the 

 doors of the boxes and the yards being raised. 



During the next six days they became thoroughly accustomed 

 to the apparatus and learned both to feed in the trough and to 

 make the trip readily from the yards, through the apparatus, 

 and back to the starting point. They very quickly and satis- 

 factorily adapted themselves to the situation, while at the same 

 time becoming thoroughly tame and indifferent to the presence 

 of the experimenter. 



