WHITE RAT AND THE MULTIPLE CHOICE METHOD 



225 



The apparatus rested on the floor on the side of the room oppo- 

 site the only window, with the entrance box nearest the window 

 and the front doors of the compartments directed toward the 

 window. The experimenter sat about 10 feet distant behind 

 a table near the window. A large mirror, hung at an angle of 

 45 degrees from the wall above the apparatus, illuminated it 

 fairly uniformly and enabled the experimenter to observe the 

 animal in positions that could not be seen directly. 



PROBLEMS AND GENERAL METHOD 



The first two of the standard problems 2 were presented to the 

 various subjects, — viz. the selection of the first mechanism on 

 the right and the selection of the second mechanism from the 

 left. Below are given the ten settings of the doors which were 

 presented in succession together with the number of the given 

 setting in the series, the number of doors open and the number 

 of the correct door. The doors were numbered from right to 

 left as viewed by the subject. 



Problem 1. First mechanism at the right end of the group 



Settings Doors open No. of doors open No. of right door 



1 1.2.3 3 1 



2 8.9 2 8 



3 3.4.5.6.7 5 ...3 



4 7.8.9 3 7 



5 2.3.4.5.6 5 2 



6 6.7.8 3 6 



7 5.6.7 3 5 



8 4.5.6.7.8 5 4 



9 7.8.9 3 7 



10 1.2.3 3 1 



Total 35 



Problem 2. Second mechanism from the left end of the group 



Settings Doors open No. of doors open No. of correct door 



1 7.8.9 3 8 



2 1.2.3.4 4 3 



3 2.3.4.5.6.7 6 6 



4 1.2.3.4.5.6 6 5 



5 4.5.6.7.8 5 7 



6 1.2.3 3 2 



7 2.3.4.5 4 4 



8 1.2.3.4.5.6.7.8.9 9 8 



9 1.2.3.4 4 3 



10 3.4.5.6.7.8 6 7 



Total 50 



2 C/. footnote 1. 



