27G ARTHUR C. WALTON 



The usual methods of avoiding possibilities of rhythm were 

 used, with the modification of keeping up the trials on one 

 compartment until a successful reaction to it was obtained. 

 The method of the experiment eliminated all possible olfactory 

 orientation or position cues. 



Delays Longer Than Fifteen Seconds. The records quoted 

 above were the highest and best results obtained, for problems 

 of the "C" types that are complete enough to be the basis of 

 claims of mastery. However, shorter series of the longer delay 

 periods were given, with the view of discovering as to whether 

 the cues used could bridge delay periods of longer duration 

 than ten seconds. On February 10th, 1914, a series of ten 

 trials of "Twenty Seconds Delay" "C3" were given, with 90% 

 of the reactions correct. In the case of the error, an interesting 

 sidelight was noticed : The dog did not 'see the stimulus, to the 

 knowledge of the observer who had watched the animal carefully, 

 but seemed intent on rubbing his nose with his paw. On re- 

 lease he automatically hurried out until in front of the com- 

 partment toward which he had faced at release. Just at the 

 entrance he seemed to realize that a choice was to be made and 

 paused suddenly, then he slowly walked to each entrance in 

 turn and looked up at the light bulb as if seeking for a cue. 

 Then he gave up and returned to the release box without making 

 an attempt to enter any of the compartments. What the mental 

 attitude of the dog may have been, the writer leaves to some 

 experienced animal psychologist to explain. On the same day, 

 the dog gave four out of five reactions correctly on "Five Seconds 

 Light and Thirty Seconds Delay," which on February 12th, 

 1914 he reacted correctly in nine out of eleven trials of the same 

 length of delay for a percentage of eighty-three. Five trials 

 on the fourteenth were all correct and of the whole number 

 of thirty-one trials, twenty-seven, or 87% were successful re- 

 actions. These trials, though rather few in number showed 

 such a constancy in the per cent of successes that the experi- 

 menters believed that strong evidence of mastery of the problem 

 was presented. 



Two series of trials of "Forty-five Seconds Delay" were given 

 on February 14th and 16th, 1914. Ten trials on the first day 

 showed only five correct responses and ten trials on the second 

 showed but six correct. Of the nine errors, five were for No. 2 



