Injected testosterone fails to influence schedule-induced attack.

Three pigeons attacked a rear-projected conspecific target during exposure to a response-independent Fixed-Time 120 sec (FT 120 sec) and food delivery schedule. After baseline attack rates were established, subjects experienced two conditions in which they received injections (IM) of testosterone (10 mg and 20 mg; 100 mg/ml, in suspension) twenty minutes before session start. No concomitant change in attack rate or temporal location of attack was observed. Findings support observations suggesting that social context is an important determiner of the effects of testosterone on aggressive behavior.