736 



W. LYNN BROWN AND ARNOLD A. McDOWELL 



O CONTROL 



• LOW DOSE 



A- — INTERMEDIATE DOSE 

 n HIGH DOSE 



Fig. 5. Mean errors to achievement of the criterion for each group on each of the 

 eight successive problems. 



dose irradiated subjects was still manifested 3 years after exposure. Inter- 

 mediate dose subjects (308 rep) that had shown no visual acuity deficit 

 during the 1st year after exposure, manifested such a deficit 3 years after 

 exposure. An interpretation of the results in terms of a basic deficit in 

 learning ability for these two groups was contraindicated by their superi- 

 ority over normal and low dose irradiated subjects on the initial and easiest 

 problem. 



Before proceeding to the research results on the second group of monkeys, 

 the field-exposed males and females, it would seem in order to show why 

 it was deemed necessary to analyze the test results in terms of the sex factor 

 as well as the radiation factor. 



Recent findings by McDowell ct al. (I960), with respect to sex as an 

 inherent difference between subjects are strikingly comparable to those with 

 respect to radiation as an experimentally induced difference. These research- 

 ers conducted a study to determine if male and female monkeys of com- 



