EFFECTS OF RADIATION ON PSYCHOLOGIC PROCESSES 



733 



50 



2 40 



30 



1-6 



7-12 13-16 



DAYS 



Fig. 4. Facilitated reduced cue discrimination performance of high dose irradiated 

 monkeys. 



cue placed over the food well containing the food reward. During the test 

 trial, the discriminable cue is removed and correct response is to that position 

 rewarded during the training trial. Analysis of the data on which Fig. 4 is 

 based, again yielded a significant groups X practice interaction. The high 

 dose irradiated subjects showed significantly greater improvement with prac- 

 tice than did the low dose or control subjects. 



The same subjects then were tested by McDowell and Brown (1959a) 

 on an oddity-reversal problem which required the utilization of the same 

 stimulus cues in antagonistic response patterns for correct solution. In the 

 original training, each subject was tested on 24 trials a day to the criterion of 

 2 successive days with two or less errors per day on response to the object 

 which was odd in color. During reversal training, each was tested to the 

 same criterion on response to the object which was odd in form. No con- 

 sistent differences were observed in the number of errors recorded by control, 

 low dose irradiated, and high dose irradiated subjects in reaching either the 

 prereversal or postreversal criterion. In achieving the criterion, all groups 

 showed a statistically significant increase in errors on reversal learning over 

 errors on original learning. The groups did show a statistically significant 

 difference in negative savings scores with the controls manifesting the least 

 savings, and the high dose irradiated subjects showing the greatest savings. 

 These results were interpreted as indicating a superiority of the irradiated 

 subjects over the controls, with respect to reversal problems of this type. 



In another study reported by Overall and Brown (1958), each day sub- 

 jects were given 42 training trials on simple black-white discrimination. 

 Eight test trials presenting two black (positive) stimuli were interspersed 

 among each day's training trials. During the test trials, the position most 



