22 WALTER S. HUNTER 



3. Raccoons 



Four raccoons, two males — Bob and Jack — and two females 

 — Betty and Jill, were tested. Bob and Betty had been pets 

 and were secured from their owner when about five or six months 

 old. Jack and Jill were caught in the woods when about two 

 and a half months old. Preliminary experiments were started 

 almost immediately with all four. The raccoons were and 

 remained in perfect health throughout the experiments. The 

 only physical defects possessed by any of them were the cata- 

 racts which developed in Bob's eyes about a month after his 

 purchase. Although this interfered with his accurate vision of 

 objects and resulted in his colliding frequently with them, he 

 was able to distinguish such changes in brightness as were 

 necessary in the experiments. This fact was demonstrated 

 conclusively by many control tests which will be described 

 later. Of the four, Betty was the quietest and most timid. 

 She w^as the least promising subject among them. Further 

 facts about these animals are given in the appendix. 



4. Children 



Five children were used in the course of the present tests: 

 two boys, Hd and L, and three girls, F, M, and H. H, Hd 

 and L were each approximately six years old. M was about 

 eight years old; and F, about two and a half. Hd and L were 

 in kindergarten work, and M and H were in the graded schools. 

 The indications were that they were children both of normal 

 ability and of nonnal intellectual advancement for their ages. 

 F was a bright little girl and made an excellent subject. All 

 of the children were more or less timid at first; but this was 

 overcome, in all save possibly H's case, before tests were begun. 

 Particular pains were taken with F. The experimenter was in 

 her company a great deal, and by the beginning of the tests 

 w^as a gladly accepted play-fellow. 



IV. APPARATUS AND GENERAL METHOD 



The plan of box A is presented in Fig. i. (This box was used 

 for the raccoons.) The box is made of I'' boards and is 2 V high 

 with doors 7 J" wide and 13" high. The light stimulus came 

 from 3 c.p. 8 volt miniature carbon lamps, so wired that they 

 might be switched on one at a time. The current was obtained 



