Chicks trained to take a food reward at the end of a runway can be distracted by changes in the appearance of either the food dish towards which they are running or of the walls of the runway remote from the food dish. Testosterone (administered as a long lasting ester 48 hours before testing) increases distraction produced by the former and decreases distraction produced by the latter manipulation. Here it is shown that these effects can be mimicked by an appropriate dose of estradiol given 30 minutes before testing. Higher doses of estradiol increase distraction (relative to controls) in both tests. The central mechanism underlying these effects may be closely linked to or identical with that responsible for the effects of testosterone on a passive avoidance task described elsewhere; these effects are also estrogenic and occur at short latency. The mechanism itself is likely to influence aspects of attention and memory processing.