SOME NOTES ON THE AUDITORY SENSITIVITY OF 

 THE WHITE RAT 



WALTER S. HUNTER 

 University of Kansas 



Since the publication of the earlier work on the auditory sen- 

 sitivity of the white rat (1), it has been possible to secure addi- 

 tional data that merit publication. Inasmuch as the material, 

 however, comes from several diverse lines of work rather than 

 from one systematic study, it is thought best to present it in the 

 form of notes. 



Mr. Otto Weir tested the sensitivity of eight rats to the tone 

 4096 d.v. sounded on a tuning fork. Of the eight rats, six 

 (rats 1 to 6) were adults and two (rats 7 and 8) were young rats. 

 Rat 6 was a female; the sex of rat 4 was undetermined; and the 

 others were males. All of the rats were untrained save rats 1 

 and 2 who had mastered the Watson circular maze. Ten trials 

 daily with punishment and reward were given using a varying 

 presentation to prevent the formation of position habits. The 

 apparatus was the same as that used in the earlier experiments, 

 consisting of the T-shaped discrimination box wired for the ad- 

 ministration of an electric shock when errors were made. This 

 box is illustrated in figure 1. The tuning fork was securely 

 clamped by the shank about 12 inches above the center of the 

 apparatus. Contact with the apparatus was possible through 

 the clamps, rods and table upon which latter the apparatus rested. 

 Pads of cotton were placed between the shank of the fork and 

 the clamps partly in order to reduce accessory vibrations and 

 partly to produce a clearer tone. No resonator was used. The 

 tuning fork was activated by striking with a metallic hammer 

 especially constructed for the purpose by the instrument maker. 



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PSTCHOBIOLOGY, VOL. I, NO. 5 



