The relationship between hormones and behavior is no longer viewed as a simple unidirectional effect of hormones on behavior. Rather, the view emerging from studies on animals observed in complex physical and social situations is that there is a sophisticated interplay between social contexts and hormonal status in the production of behavioral interactions. The present studies will further illuminate these relationships in callitrichid primates (marmosets and tamarins). Dr. French has previously shown that social relationships within mated pairs are extremely important in regulating the influence of hormones on behavior. The current studies will evaluate the effects of other social factors in modulating hormones effects on behavior. Specifically, Dr. French will assess whether or not responses of tamarins to unfamiliar intruders differ as a function of the intruding or resident female's reproductive status, will assess whether or not reproductively suppressed subordinate females are capable of expressing patterns of reproductive behavior when removed from the social context that produces suppression, and will evaluate the influence of visual access to unfamiliar pairs on patterns of reproductive behavior across the ovarian cycle. These studies are important in a number of ways. First, the work is relevant to propagation of endangered species. All marmosets and tamarins are considered threatened or endangered, and for some species (e.g., lion tamarins) there are more individuals in captivity than in the wild. It is highly likely that information critical for the enhancement of the propagation of these species in captivity will be the direct result of these studies. Hence, this research may have a profound impact on the maintenance of the biodiversity of tropical animals. Second,these studies will show how complex social settings can influence (reduce or magnify) the effects of internal physiological functions on behavior. These findings as a whole will contribute to a more complex and realistic view of hormones and behavior. Finally, these studies will evaluate hormone-behavior relationships in species of primates that have a social system with many common features of human societies (e.g., high degree of cooperative behavior, joint rearing of offspring, residence of older offspring in family or social groups).
