Jenna Jackson, Brigham Young University
Psychology
We examined the effect of social separation stress and serotonin transporter genotype (5HTT) on behavior during mother-infant (MI) reunions using infant rhesus macaques. Based on previous studies, we predicted that infants and mothers who posses the less efficient short (s) allele would display more anxious and aggressive behaviors in both their relationship and also within the larger social group. MI behaviors were recorded during a reunion period after being separated for five days from their mothers. Subjects were 140 rhesus macaques that were tested in one of two separation conditions: mother removed from the social group with the infant left behind, or the mother and infant were each housed alone in single cages. Time spent in behaviors that characterize MI and peer relationships were recorded as dependent variables, while genotype was used as the independent variable. Results showed that MI interactions were especially affected if both the mother and the infant possessed the Ls genotype. Moreover, infants with the Ls genotype also displayed less social contact with other group members, and higher rates of aggression with their peers. Our findings suggest that when both the mother and the infant possess the 5HTT short allele, the MI relationship is strained, showing higher levels of stress and that peer bonds are also affected negatively by the Ls genotype. To the extent that our findings generalize to the human condition, they suggest that the 5HTT genotype influences environmental conditions to influence the mother-infant bond and other social interactions.