256 F. M. GREGG AND C. A. McPHEETERS 



as we have asserted, the two groups are relative to each other, 

 yet they cannot be completely relative. The stimuli must 

 also possess certain fixed, definite and absolute attributes and 

 this feature is furnished by the above characteristics of differ- 

 ence or identity of component elements. The group 3-2-1, 

 given in conjunction with 1-1-1, would be selected as negative 

 so far as the animal was depending upon the factor of relativity 

 of depth distinctions, but it would likewise be regarded as posi- 

 tive in so far as the animal was influenced by this definite char- 

 acteristic, viz., a series composed of different elements. The 

 anomalous results of the first test are thus explicable on the 

 assumption that the two effective factors of each group stim- 

 ulus were brought into antagonism. In the normal series, one 

 stimulus invariably consisted of a succession of identical ele- 

 ments (3-3-3), while the other stimulus was invariably composed 

 of a succession of different elements (1-2-3). O ne nas a right 

 to assume that the animal in learning to distinguish the two 

 will rely to some extent upon every available distinctive aspect 

 — upon the factor of identity versus difference of elements as 

 well as upon relative nearness or distance of the groups. The 

 writers incline to this hypothesis because it harmonizes with 

 and supplements the conclusions previously enunciated. This 

 explanation of the results of test no. 1 furnishes additional 

 evidence in support of our previous contention as to effective- 

 ness of the second member of the group stimulus. 



It is evident from our results that Cole's conclusion as to 

 a discrimination based upon visual peculiarities of the cards 

 is an unwarranted assumption. He did not (so far as can be 

 determined from his account) eliminate the possibility of a 

 discrimination based upon cues from the experimenter, or upon 

 his method of lever manipulation. The discrimination may 

 have been tactual as in the case of our animal. Cole describes 

 his animals as standing with forepaws upon the card displayer 

 and clawing at the levers, and our raccoon which stood in such 

 a position that contact was impossible failed to master the 

 problem. However, we do not wish to make any conclusions 

 as to Cole's animals; we merely wish to point out the naive 

 anthropomorphism underlying his statement of fact. 



His conclusion as to the efficacy of the third lever in the 

 positive series is valid, but he fails to distinguish between a 



