BEHAVIORAL EFFECTS OF RADIATION ON PRIMATES 721 



Observations of behavior were made at frequent intervals by various in- 

 vestigators, including H. W. Nissen, A. A. McDowell, C. S. Ferster, L. J. 

 Peacock, C. M. Rogers, and myself. Tests were selected to cover a wide 

 range of performances and to challenge a variety of skills and capacities at 

 difTerent levels of complexity. 



In some tests the animal was required to move quickly; in others, it had 

 to make an appropriate repetitive response. Tests involved food and other 

 rewards. Some tests required the detection of small or obscure stimulus dif- 

 ferences; in others, spatial memory was challenged. 



Many of the tests were presented in the apparatus shown in Fig. 1. A 

 retractable gray tray bearing test stimuli is propelled against the wire mesh 

 of the cage. The stimuli, in this case two different wood objects, cover food 

 wells. If the animal displaces the correct stimulus, he obtains food. Usually 

 the animal's task is to discover (learn) which object consistently covers the 

 food. An opaque screen immediately in front of the animal can be lowered 

 while the stimuli and rewards are being arranged for the next trial. 



/ Results 



The adults, especially the females, appeared to show the effects of radia- 

 tion sickness more than younger animals. Onset of the acute deterioration 



Fh;. 1. Ciliiiiijjaiizee displacing stimulus object from food well to obtain reward. 



