New Findings In Developmental Research With Animals

Abstract

Contained in this month's Journal is a review article by Stevens and coworkers ( p. 114 ) that summarizes research on gene-environment interactions in macaque monkeys. Whereas studies in humans have received a tremendous amount of recent interest within our field, there has been a great deal of parallel research in animals that is less known. Beginning with some of the landmark work by Harlow and colleagues 1 Harlow HF Dodsworth RO Harlow MK Total social isolation in monkeys. Proc Natl Acad Sci USA. 1965; 40: 338-352 Google Scholar on the long-standing effects on young monkeys of early maternal deprivation, research has continued to extend and refine these early studies. Young rhesus macaques show a range of temperamental traits in proportions similar to infants and toddlers. These traits show some stability into adulthood. Peer-reared animals and those raised under variable foraging conditions show higher levels of both anxious and aggressive behavior through development—a combination commonly seen in child clinics but one that often presents challenges to the diagnostician. These behaviors are correlated with alterations in brain function. As in humans, the behavioral and physiological effects of these early experiences seem to be moderated by genes. In addition, an infant monkey's genotype, perhaps operating through its temperament, can elicit suboptimal parenting responses in otherwise competent macaque mothers.