Response of adolescent bonnet macaques to an acute fear stimulus as a function of early rearing conditions.

When primate infants are reared during the first half-year of life in an environment in which their mothers face uncertain requirements for food procurement (variable foraging demand [VFD]), long-lasting behavioral and neurodevelopmental consequences ensue, including increases in timidity and social subordinance as well as alterations in stress-related neuroendocrine profiles. We examined the nature and persistence of the effects of VFD rearing by exposing VFD-reared and normally reared adolescent bonnet macaques to a mild fear-provoking stimulus 2 years after the end of differential rearing. VFD-reared subjects at baseline were less gregarious than normally reared monkeys. VFDs also were considerably less responsive to the fear stimulus, and their behavior and affect returned to baseline levels more quickly than normally reared subjects. The extent and persistence of the sequelae of VFD rearing suggest parallels with predisposing factors in human anxiety disorders.