64 WALTER S. HUNTER 



sibly olfactory differences in the boxes used by the animals due 

 to the animal odor itself and (in the case of the rats and rac 

 coons) to a food odor set up by the milk that was on the fore- 

 feet of these animals. Suppose now that these simultaneously 

 present external factors be treated in their entirety for each box 

 and be represented by the letters x, y and z. It may be assumed 

 that the subjects learned to react not to the lights — a, b and c 

 — alone, but to the complexes ax, by and cz. Then when the 

 delays were begun, the reactions were made to x, y and z, either 

 immediately or after a period of learning. Here we would have 

 three cues governing as many reactions, and all three cues 

 would be presented simultaneously at the moment of release 

 whereupon the reaction would take place. 



This hypothesis is not supported by the experimental facts. 

 If the reactions during the delay were determined by these 

 stimuli present at the moment of release, the animals should 

 have learned to delay for almost any interval of time. It should 

 be no more difficult to react to x, y and z, than to the lights, 

 since the reactions during delays were just as "precipitate" 

 and "headlong" as when the lights were present. Now it was 

 demonstrated that all of the animals could react perfectly when 

 held in the release i min. with the light on. Why then could 

 they not delay a minute with the factors x, y and z which were 

 also constantly present? Further, if the subjects succeeded in 

 reacting to x, y and z for intervals of 5 or 6 sees., why should 

 . they be unable to reach 7 or 8 sees. ? In other words, why, 

 if they reached one stage of delay on this basis, should the 

 subjects not go a little beyond and so up to a large delay? There 

 is no answer to this, if one assumes, as we have done, that the 

 cues are simultaneously present at the moment of response. 



In the section on experimental results, tests were described 

 where the entire sides of the problem box surrounding the 

 entrances to the light boxes were covered with cardboards of 

 widely separated grades of brightness. This device accentuated 

 (from the experimenter's point of view) the constant differences 

 between the hypothetical stimuli x, y and z, yet under these 

 conditions neither rats, dogs nor raccoons showed improvement 

 in their abilities to react. This series does not prove that no 

 objective factors x, y and z were influential in initiating behav- 

 ior; but, in conjunction with the immediately following theoret- 

 ical discussion, it does make it very improbable that such fac- 



