AUDITORY SENSITIVITY OF THE WHITE RAT 351 



clearly rejected from the class of interrupted noises. Because of 

 the rat's refusal to class the metronome at 160 with the 

 intermittent noises, the results are not so clear cut as might be 

 desired. However, as with rat 7, the indication is that the 

 frequencies around 200 are the critical ones. 



It seems probable that the discriminations here made by the 

 two animals were discriminations of " qualities" rather than of 

 "rates." The difference between the noise group of hissing, 

 buzzing and "rush of air" and the noise group of handclaps and 

 slow metronome beats is the qualitative difference of continu- 

 ous and intermittent pointed out by Hensen. The indications 

 are, therefore, that for the white rat there are two classes of 

 noises beats are apparently not sensed. 



REFERENCES 



(1) HUNTER, W. S. : The auditory sensitivity of the white rat. Jr. Animal 



Behav., 1914, 4, 215-222; and 1915, v, 312-329. 

 HUNTER, W. S., and YABBROUGH, Jos. U. : The interference of auditory 



habits in the white rat. Jr. Animal Behav., 1917, vii, 49-65. 

 BARBER, A. G. : The localization of sound in the white rat. Jr. Animal 



Behav., 1915, v, 292-311: 



(2) WYLIE, H. H. : Some experiments on transfer of training. Psych. Bull., 



1916, xiii, 78-79. 



