Effects of testosterone on the behaviour of the domestic chick. II. Effects present in both sexes.

In female chicks, testosterone increases both binocular fixation of the thrusting hand and avoidance of direct gaze. The hand is thus treated as though it had become more conspicuous. Males show signs of such changes, which are obscured by a progressive locking of attention on the hand, along with which develop head shaking and pecking. These latter three effects, together with later full attacks, may be a consequence of increased persistence in males due to testosterone. In both sexes testosterone facilitates waltzing and three characteristic calls, probably by specific effects. Latencies and dosage dependency are similar in both sexes. Ten changes in behaviour due to testosterone can be explained by as few as five basic effects, both general and specific.