342 WALTER S. HUNTER 



exceed 60 per cent, although the normal conditions gave 73 to 

 80 per cent correct response. Clearly something was eliminated 

 that had served to determine the rats responses. The results, 

 however, do not prove tone sensitivity because the "thud" 

 caused by the free fork was different from the "thud" of the fork 

 when held and may have served as the basis of the original 

 discrimination. 



Control 2 did not disturb the accuracy of the rat's responses. 



Control 3 was given one day with an accuracy of 50 per cent; 

 two days, with 70 per cent; and one day each with 60, 50, and 

 40 per cent. In this control the stimulus used for each trial was 

 the same. The results of this control indicate, therefore, that 

 a high percentage may be made without using an auditory cue. 

 They are also partly in harmony with the view that the original 

 response was influenced by the differences in the noises involved. 



These three controls have not determined the exact basis of 

 the response during the normal tests. Inasmuch as the percent- 

 age of correct responses was not stable during those tests, and 

 was not particularly high, it seems probable in the light of these 

 controls and of other published work, that rat 3 was not reacting 

 to tone stimulation. 



ii 



The experiments on audition to be reported in this section 

 were made in the summer of 1914 and again in the spring of 1915 

 at the University of Texas. In the course of some correspond- 

 ence, Professor Carr of the University of Chicago described some 

 of the work then being carried out at that university by Mr. 

 Harry Wylie on transfer of training. At that time the present 

 writer was making a study of auditory sensitivity and of habit 

 interference as published in the 1915 and 1917 articles listed 

 above. The methods and apparatus employed were peculiarly 

 adapted to the study of Wylie's method dealing with transfer 

 between sense fields. The method of inter-sense transfer was 

 therefore employed with the result that valuable data bearing 

 upon tone sensitivity were secured. This data was not made 

 public until Wylie presented his report at the 1915 meeting of 



