Sex hormones and cognitive functioning in men.

Blood and saliva samples were obtained from 117 healthy young men, following which radioimmunoassays were used to determine the serum concentrations of testosterone (Tser), 5 alpha-dihydrotestosterone (DHT), and the level of free testosterone (Tsal) in the saliva. The cognitive functioning was determined by five spatial and six verbal ipsative test scores, reflecting intra-individual variance in the performance of these tasks, independent of the person's general level of achievement. Within the normal physiological range of androgen levels--especially Tser and to a lesser extent DHT and Tsal--showed a significantly positive correlation with measures of spatial ability and field dependence-independence and a significantly negative correlation with measures of verbal production.