Early determinants of behaviour: evidence from primate studies.

The idea that early experiences disproportionately influence adult behaviour has long been a fixture of mainstream developmental theory. Although unambiguous empirical support for this view at the human level is surprisingly sparse, compelling evidence from animal studies abounds. Recent studies with rhesus monkeys have demonstrated dramatic short- and long-term effects of differential early social experiences on both behavioural and physiological functioning. Early social relationships with mothers or other caregivers appear to provide especially powerful determinants of behavioural propensities throughout the lifespan.