Early experience and socioemotional development in young rhesus monkeys

This project tests the novel hypothesis that exposure to moderate levels of maternal rejection early in life “inoculates” the developing infant by permanently altering cognitive appraisal of, and neuroendocrine sensitivity to, subsequent stressors (i.e., stress resilience). In contrast, we posit that exposure to too little or too much rejection-related stress leads to stress vulnerability later in life. We also test the hypotheses that these maternal influences on the development of stress resilience and vulnerability 1) result from long-term alterations in the activity of oxytocin biology, the serotonergic system, the hypothalamic-pituitary-adrenal HPA axis, and other stress-sensitive neurobiological systems, and 2) are modulated by risk or protective factors such as polymorphisms in the serotonin transporter gene and amount of social support. This 5-year project is being conducted with the free-ranging population of rhesus macaques on Cayo Santiago, PR. This research will provide original information on the neuroendocrine mechanisms through which exposure to variable parenting can affect the development of stress vulnerability and resilience in children, and how genetic and environmental factors may influence these development outcomes.