Dr. Stephen J. Suomi, chief of the Laboratory of Comparative Ethology at the National Institute of Child Health and Human Development, gave a presentation in March as part of Marymount’s Distinguished Visiting Professor Colloquium Series.
Dr. Suomi’s research on biobehavioral development in rhesus monkeys and other primate species has received worldwide attention. His work focuses on the interaction between genetic and environmental factors in shaping individual development; issues of continuity versus change and the relative stability of individual differences throughout development; and the degree to which findings from monkeys studied in captivity can be generalized to monkeys living in the wild, and even to humans living in different cultures. Since rhesus monkeys mature four times faster than humans, Dr. Suomi has been able to study several generations of the animals during the course of his career.
In his presentation at Marymount, Dr. Suomi highlighted the fascinating links between humans and rhesus monkeys, noting that the two species have 95% of the same genes in common. In the wild, rhesus monkeys live in troops organized around a matriarchal society and develop strong family loyalties. They are also resilient, like humans, and can adapt to living in diverse environments.
Dr. Sumoni’s research confirms that, just as with humans, rhesus monkeys’ early environmental experiences make a difference in the development of their personalities and social skills. His work has shown that, under the best circumstances, infant monkeys have strong bonds with their mothers. As they grow, they spend several years in their troop’s protective care, playing with their peers, and developing good socialization skills. But those monkeys who are deprived of a mother figure are peer-raised and suffer from the lack of parental attachment. This upbringing often leads to aggressive and risk-taking behavior, especially in those individuals that are genetically predisposed to such behaviors.
Dr. Suomi also examines the monkeys’ genetic make-up, with a specific focus on alleles that affect serotonin production. Monkeys with low levels of serotonin, a brain chemical that affects mood, are more predisposed to aggressive, violent behavior. However, Dr. Suomi concludes from this research that such genetic tendencies can be mitigated by the right kind of interaction between mother and child. He told his Marymount audience, “Early experience is absolutely crucial. Good mothering has a buffering effect on aggressive behavior.”