STIMULI DURING DELAYED REACTION IN DOGS 283 



of seventy-one. On February 21st, twelve trials were given 

 and of these trials 2, 4, 5, 6, 7, 8, 9, 11 and 12 were correct re- 

 actions giving a percentage of seventy-five. This series gave 

 six successive correct reactions in trials four to nine. On the 

 19th, nine trials on a one minute delay were given and 66-2/3% 

 of them were correct reactions. The last five were 100% correct. 

 These experiments showed that the dog was able to accurately 

 discriminate the stimulus from four compartments, that were 

 only two feet apart, and that he was able to retain the cues 

 to this discrimination over a delay period of at least one minute, 

 without showing signs of a break-down in the cues to any one 

 of the compartments. 



RESUME OF RESULTS 



The first conclusion drawn from the records was that perfect 

 mastery could not be gained because of the vacillating factor 

 of attention. This factor was high enough to give practical 

 mastery of the problems, but failed to give perfect mastery. 

 Sheepish behavior was apparent whenever the dog did not feel 

 exactly right, or when he made several unsuccessful trials in 

 succession. After such a period of failure the dog would hesitate 

 for fear of more mistakes, and in doing so would fail to get the 

 stimulus and make the association. This sheepish action was 

 the cause of a large percentage of the failures to make the correct 

 reaction. It was found, however, that allowing the dog to 

 return to the release box at his own will did away, to a great 

 extent, with sheepish actions. If the dog was always called 

 back, after several failures he would become discouraged and 

 give up trying. If he was left to his own devices, after several 

 failures he would lie down and rest for perhaps two minutes 

 and then return of his own free w T ill and try over again with 

 his attention and interest as alert as ever. No sign of sheepish 

 behavior appeared then. 



The records also show the contrast between the different 

 parts of the experiments, i. e. the routine of leaving the release 

 box when the door was opened, and that of making the correct 

 reaction to the stimulus given. Often when he refused, through 

 discouragement, to make a choice of compartments, he went 

 through the routine part without a hitch. It was found, how- 

 ever, that extreme discouragement affected even the routine 



