Figure 2.

Adaptive modulation of behavioural profile in adolescent males. Variation in social environment (low versus high individual numbers) during this phase of life triggers endocrine pathways that result in behavioural profiles and strategies that match the current environmental situations. Note that concerning testosterone a specific organizational effect on HPA responsiveness is suggested that probably occurs at just this period of life. Possible activational effects of increased testosterone on aggression are not addressed. Reprinted from Sachser et al. [4] with permission from Elsevier.