172 



BINNIE D. PEARCE 



The object of control 2 was to determine the similarity of the 

 8 and 32 c.p. stimuli in terms of response. A summary of the 

 control tests is given in table 2. The chronological order of 

 records has been preserved. The per cents represent correct 

 responses in a given daily series of 10 trials. The low percent- 

 ages made with control 1 indicate the rats' dependence upon 

 the light as a determining stimulus. The high percentages made 

 with control 2 indicate that the rats sensed the light and that 

 it meant to turn to the right in order to secure food. The ex- 

 ceptions to this statement are shown in the table. 



TABLE 2 



Controls Used With Habit No. 1 



Rats 



Control 1 2 3 4 10 13 14 15 



Control 1 50% 80% 40% 50% 60% 60% 50% 50% 



Control 1 60 ' 



Normal 90 100 90 100 90 100 90 90 



Normal 90 



Control 1 50 . . 60 50 20 50 40 70 



Normal 100 .. 90 90 60 100 90 90 



Normal 90 



Control 2 50 90 70 80 80 100 70 100 



Control 2 80 



Normal 60 100 90 90 90 100 70 100 



Normal 100 



Control 2 50 60 70 70 70 90 40 80 



II 



Training on the second habit was instituted in the case of 

 each rat as soon as the results of the first test had been analysed 

 by controls as shown above. The second habit furnished a 

 problem the opposite of habit No. 1. Its purpose was to train 

 the rats to associate turning to the left with the presence of 

 light and to the right for the absence of light. The 8 c.p. light 

 of the control tests was the stimulus here. At first it was 

 shaded by three thicknesses of the writing paper. But when 

 rat No. 3, the first rat tested on habit 2, persisted in reacting 

 to this stimulus as he did to the absence of light, I removed one 

 thickness. The purpose was to secure a light which would be 

 treated the same as the standard light and yet which should 



