52 



WALTER S. HUNTER AND JOS. U. YARBROUGH 



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300 yoo 



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Figure 1. — Distribution curve of the original learning 



the least ambiguous. The accompanying table (No. 2), how- 

 ever, will show that an extended use of the control produced 

 low percentages. Control 2, where the buzzer was substituted, 

 gave the following results: On the first day, 7 rats (Nos. 15, 

 18, 20, 22, 9, 10, 11) made below 80%. On the second day, 5 

 rats (Nos. 20, 22, 10, 11, 14) made below 80%. On the third 

 day, 3 rats (Nos. 21, 8, 11) made below 80%. On the fourth 

 day, Nos. 9 and 14 fell below 80%. Seven rats (Nos. 1, 4, 7, 

 16, 17, 19, 23) never fell below 80%. The adjustment or trans- 

 fer was thus usually made either at once or by the end of the 

 second day. On control 3, 6 rats at different times made a 

 day's record with 80% correct. This occurred, however, with 

 a majority of days at 50, 60 and 70% and is to be regarded 

 not as evidence of auditory sensitivity, but as an accident in 

 the grouping of kinaesthetic factors. 



TABLE 2 



Records on Controls Giving Correct Choices Out of 10 

 The text states that not all records are from successive days 



Rat 



15 



16 



17 



18 



19 



20 



21 



22 



23 



1 



4 



7 



8 



9 



10 



11 



14 



Con. 1 



6,5, 6 



7, 4 5 



8! 5, 7, 8, 6, 5 



5, 6, 6 

 4,5,7 



6, 6, 6 

 6, 6, 5 



6, 5, 5 

 5, 5, 7 



6.5, 6 

 6,7,5 



7, 7, 6 

 5, 6, 6 



6.6, 6 

 6,3,4 



5, 3, 5 



6, 5, 6 



Con. 2 



5, 10, 8, 8 

 8, 9, 10, 8 



8, 9, 8, 9 



6, 8, 9, 10 

 10, 10, 9, 9 



7, 5, 10, 9 



9, 9, 6, 9 



7, 6, 8, 10 



8, 8, 9, 9 



10, 8 



9, 10, 8, 9 

 9, 10, 8, 8 

 9, 8, 7, 8 



6, 8, 9, 6 



7, 5, 8, 10 



7, 5, 6, 9 



8, 7, 9, 6 



Con. 3 



7,6, 7 

 6, 6, 8, 6 

 8, 7, 7, 10, 7, 7 

 8, 9, 5, 8, 5 

 6, 7, 8, 7 



6, 6, 5 



7, 6, 7 



6, 7, 4 



7, 8, 7, 7 

 6,5,5 

 6,7,5 

 5,7,7 

 6,6,7 

 5,6, 5 



7, 6, 6 

 7, 6, 8, 6 

 5,6,7 



