36 WALTER S. HUNTER 



more or less completely broken down in their reactions to one 

 box. Tests with two boxes were never made on any subject, 

 unless the animal lost the cue to one box. It was this box 

 that was dropped from the series. The maximum delays made 

 by the rats under these conditions were increased. Nos. ii, 

 15 and 16 each made 5 sees, at from 76 to 90%. This must 

 mean that it is easier to use two cues than three. Further 

 comments will be added below (see p. 39). 



Of the dogs, Blackie made 10 sees, at 76% for 30 trials. She 

 then lost the cue to one of the boxes and was unable to react 

 successfully to that one. When tested with two boxes she 

 finally made a delay of 5 mins. for 5 trials at 80%; 86% had 

 been made at 3 mins. for 30 trials. Brownie was tested only 

 with three boxes. She made a delay of i sec. for 50 trials at 

 90% and 2 sees, for 70 trials at 68%. Both dogs were tested 

 for eight months. The results should be representative of what 

 dogs can do under the present conditions. 



Of the raccoons, Jack made 14 sees, at 70% for 30 trials. 

 Tested with two boxes, he finally made 85% at 20 sees, for 40 

 trials. He was tested for eight and one -half months. Betty 

 made 82% at 7 sees, for 50 trials. Tested with two boxes, she 

 reached 10 sees, at 86% for 30 trials. She was tested for one 

 year and three weeks. Jill was tested only with three boxes. 

 She made 3 sees, for 45 trials at 93%. The tests extended 

 over a period of seven months. Bob made 90% for 10 trials 

 at 15 sees. Tested with two boxes, he reached a delay of 25 

 sees, for 20 trials at 90%. Bob was tested steadily for a 

 year and five months. 



For fear that some critic would urge that the animals could 

 not have delayed longer than they did even though the light 

 had been constantly present, control tests were made as fol- 

 lows: The animals were taken at the stage when they had 

 just broken down at some (for them) long interval of delay 

 and were held in the release for one minute with the light on. 

 When they were released, the light was still left on. The results 

 show that the animals made a very high percentage of correct 

 behavior. Their failure to make correct long delayed reactions 

 must have been due, then, to their inability to use some cue 

 by which to guide their reactions after such an interval and not 

 to mere restlessness caused by the long confinement. 



