270 ARTHUR C. WALTON 



from the ease with which the dog made the reactions, the experi- 

 menters were satisfied that with the same degree of attention 

 as then displayed, further trials would only definitely show that 

 the dog could retain his cues to reaction over a delay period 

 of at least twenty seconds. As later trials will show, this assump- 

 tion was not unfounded. 



Condition "J3." — Condition "B" means that the results here 

 were made under conditions in which the release box faced 

 the food compartments only during the stimulus and delay 

 periods. The dog could not see the operator adjust the lights 

 and so could not gain any possible position cue to the right 

 compartment from his movements. Also the possibility of 

 smelling the food was removed, for in all the "B" trials, the 

 food was thrown to the animal after the successful completion 

 of the reaction. 



B2 — The results here embraced the following series: 



Light out at release .... 92 trials 44 correct 48% 



Five seconds delay 80 trials 48 correct . 60% 



Ten seconds delay 25 trials 1 1 correct 44% 



Fifteen seconds delay. . 14 trials 6 correct 45% 



These results are not high but nearly all well above a chance 

 percentage of successful reactions. The averages obtained were 

 about the same as those of the same length of delay in the "A" 

 types and the differences are too slight to be explained on any 

 ground, but that of the attention of the dog, which varied with 

 his physical and pyschical state. It was noticed that the mid- 

 dle compartment seemed to be discriminated more correctly 

 than the other two, so check experiments were given in the 

 "Out at Release" to see if this was really so. On No. 1 com- 

 partment, seventeen trials gave six correct reactions, or a per- 

 centage of 35. Compartment No. 2 gave seven out of ten, 

 or an average of 70%, while No. 3 compartment showed 

 only thirteen out of forty-five trials correct. This last result 

 confirmed the conclusion that the cues to No. 3 were weak and 

 that more training was necessary before correct discrimination 

 could be shown. 



Close observation of the behavior of the dog showed that he 

 avoided the right side of the room on which No. 3 compartment 

 was situated because of the intensity of the light. Finally he 



