DELAYED REACTION 65 



tors should have exercised a determining influence on the 

 reactions. 



Let us grant for the moment that such objective factors 

 were present, could they alone control successful reactions, i.e., 

 could they be the determining factors in initiating correct de- 

 layed reactions? Since x, y and z are present simaltaneonsly at 

 every response, they per se cannot be the bases for differential 

 responses. The subject must select one of the boxes. Hence 

 the hypothesis would need to assume that the subjects are not 

 reacting merely to x, but to x-where-the-light-has-just-been. 

 Here we are forced face to face with the problem from which 

 we started: What represents, or is a substitute for, the light? 

 What is the element attaching to x that is equivalent to " where - 

 the -light -has just-been " ? There can be no question but that 

 x, y and z in some form constituted a part of the general stim- 

 ulus, for the subject must apprehend the different spatial loca- 

 tions of the boxes in order to react to them. The objection 

 may be offered that this contention as to the effectiveness of 

 these objective stimuli is inconclusive, inasmuch as the animals 

 may have been reacting entirely in terms of kinaesthesis, i.e., 

 had learned the fixed order in which the three boxes were pre- 

 sented. This possibility was adequately eliminated by control 

 tests whose results are discussed on p. 67. The point to be 

 established here is that x, y and z could not have been the 

 crucial substitutes for the lights. These must have been fac- 

 tors which were not all simultaneously present, each in its 

 entirety, at every response, i.e., they must have alternated 

 from trial to trial, depending therefore on the position of the 

 light. The question now is: Were there any such factors in 

 the objective environment? 



(b) Alternating objective cues. — Controls were instituted: 

 (i) To prove that during the learning series the light (an alter- 

 nating factor) was the determining cue for the reactions ; and 

 (2), to prove that in the absence of the light no other external 

 factor took its place as a determinant of the reactions. 



I. The reagents did not derive any cues from the experi- 

 menter. Screens were so arranged that the operator was never 

 visible to the dogs. Control tests were also made under these 

 conditions with the rats, raccoons and children. The constant 

 beating of a metronome covered up any noises due to the ex- 



