ON SOUND DISCRIMINATION BY CATS 71 



the Johns Hopkins University, got some positive results. How- 

 ever, I am informed in a verbal report of the experiments by Dr. 

 J. B. Watson, that an average of only about 60 per cent, of correct 

 responses was obtained. 



At the time the experiments herein reported were begun, one 

 of the animals was eighteen months old. Its only previous 

 training had been in some tests on discrimination of articulate 

 sounds, completed about nine months previously to those ex- 

 periments. The animal appeared to be of medium intelligence. 

 The other cat, the mother of the first, was about four years old. 

 It had received the same training in sound discrimination as 

 the other animal, and at the same time. The latter cat was of 

 average intelligence. Both were ordinary grey house cats. 



In the experiments on pitch discrimination to be reported in 

 this paper, I used the same plan as I had employed in the ex- 

 periments with the raccoons and with the monkeys, and which 

 is somewhat similar to the method Kalischer employed. The 

 cat was placed in a cage 66 centimeters in height. A wire netting 

 formed the front, and also the top of the cage. The experimenter 

 sat at a distance of about a meter from the cage and sounded a 

 certain note on the instrument used. At this note, in the case 

 of the first animal, Pet, the cat was to rear up with its paws on 

 the front of the cage and look up through the top of the cage 

 for food to be given it. At the other notes, it was not so to react. 

 In the case of the second animal, Mary, on account of its inactive 

 habits, as shown in previous experiments, it was deemed a suffi- 

 cient response if it merely looked up at the top of the cage for 

 food, when the ' feed " note was sounded. But whether or 

 not a positive response was obtained, the animals were fed when 

 the " feed " note was sounded. Ten seconds were allowed for a 

 response. In experiments 1 and 2, an ordinary harmonica, A, 

 was used; in experiment 3, a Bradbury piano; the procedure in 

 experiment 4 will be explained under that head. In each test, 

 care was taken not to give by looks, movements of the hands, or 

 in any other manner, any cue to the proper response. In order 

 that the animal might not react to the mere rhythm of the sounds, 

 they were sounded in an irregular order. 



1. Discrimination of a Difference of Two Octaves of Pitch 

 on a Harmonica. A-3, Food Note; A-l, Non-food Note. 



Pet. — In the first day's experiment, this animal showed 



