THE AUDITORY SENSITIVITY OF THE WHITE RAT 



WALTER S. HUNTER 

 The University of Texas 



(One Figure) 



The following is a report upon some studies of the auditory 

 sensitivity of the white rat which are in progress at the psychology 

 laboratory of the University of Texas. In January, 1913, tests 

 were begun upon the discrimination of noise and tone in order 

 to ascertain whether for the rat these are sensed as different. 

 The discrimination box was T shaped. (See figure 1.) The 



Figure 1. T-shaped discrimination box. F, food; R, release box; X, tuning 

 fork was held above this point; A, alley stop, can be placed in either alley; S, switches. 



animal was started at the base of the T and was required to turn 

 either to the left or to the right depending upon the stimulus 

 given. The source of the tone was a tuning fork held in a clamp 

 above the apparatus and actuated by striking with a rubber 

 hammer. The fork support was mounted independent of the 

 apparatus box so that mechanical jars could pass through the 

 floor only, if at all. The experimenter was prepared to intro- 

 duce electric tandem driven forks, but this was found unnecessary. * 



i In order to make it difficult to use the thud of striking the fork as a cue, the fork 

 was struck just as the rat was placed in the release box. In order to make the con- 

 trol more sure, the fork may be actuated even sooner. While in crucial cases, this 

 method cannot supersede the tandem driven forks, in the average case it may render 

 the use of such apparatus unnecessary. 



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