Testosterone influences volitional, but not reflexive orienting of attention in human males

The impact of testosterone (T) on the exogenous (Experiment 1) and endogenous (Experiment 2) orienting of visual attention in males was examined. Sixteen male participants completed both an exogenous and an endogenous cuing task on two separate days. About 2-3h prior to testing, either a placebo or a dose of T was administered. The inhibition of return (IOR) phenomenon was observed during the exogenous cuing task, but IOR was not influenced by T. During the endogenous task, participants demonstrated the expected cuing effects on both days. However, longer reaction time to invalid target locations was observed following T-administration. The manipulation of T-levels in males provides converging evidence of dissociation between reflexive and volitional orienting of attention.