102 JOSEPH U. YARBROUGH 



TABLE VI — Continued 



Maximal Number Per cent 



Animal delay of trials correct 

 Raccoons — ■ 



Jill 3 sees. . . . 93 



Jack 20 sees. ... 85 



Bob 25 sees. ... 90 



Walton Dogs 10 sees. ... 64 



Present work . . Cats — 



Set A (light) Bobbv 4 sees. 160 85 



Jim... 4 sees. 120 78 



Set B (sound) Bess . 4 sees. 170 71 



Phil . 2 sees. 40 83 



It will be noted that the longest delay mastered by the cats 

 was a period of four seconds. I am sure that with continued 

 training they can bridge a much longer period than this. But, 

 since I was more interested in the behavior during delay than 

 in the maximum period of delay; and since at this point there 

 had developed a tendency to drop out the middle box; and, again, 

 since time was limited, I thought it best not to give further 

 training on three boxes. 



(d) Longer delays. — ■ 



Scattered throughout the experiments are correct reactions 

 over periods of delay much longer than those mastered in the 

 regular series. These periods were willingly lengthened by the 

 subjects themselves. This in itself is good evidence that with 

 sufficient training a much longer interval of delay could be 

 mastered. At three different times Bess made 9 correct reac- 

 tions out of 10 trials with a delay period of six seconds. And, 

 at another time she made, with the same interval of delay, 17 

 correct responses out of 20 trials. Twice she responded cor- 

 rectly after a delay period of twenty-six seconds. It will be 

 recalled that Bess was tested on sound. Jim, also tested on 

 sound, bridged at one time a period of eight seconds, at another 

 a period of eighteen seconds, and a third of thirty-four seconds. 

 The cats on light seemed not to have hesitated so often as did 

 those on sound. In all the work on the three box experiments, 

 Bobby was the only cat tested on light who voluntarily length- 

 ened her period of delay. On this occasion she sat for sixty-six 

 seconds in the release box, after which she went directly to the 

 proper compartment. All the periods of hesitation were not 

 measured and tabulated. Animals, both of Set A and Set B, 



