Title: Genetic and Developmental Risk Factors for Impulsivity and Aggression in Rhesus Macaques (Macaca mulatta)
Name: Erin Kinnally
Year: 2007
Type: Dissertation Fellowship
Summary: One of the primary psychological foundations of characteristic exhibition of aggression is trait impulsiveness. Individuals who are unable to plan ahead or to inhibit their behavior are more likely to exhibit violence (humans, Caspi and Silva, 1995; rhesus macaques, Heinz et al., 1998). The development of impulsivity as a trait depends on gene-environment interactions that impact brain development, brain function during infancy, early temperament, and ultimately, adult behavior. Rhesus macaques provide an excellent model for human bases of aggression. Exhibiting similar genetic, physiological, and early environmental risk factors for developing aggressive tendencies, the rhesus macaque model allows us to trace more specifically the causal pathways of aggression than is possible in human research. The work completed during the award period aimed to assess psychological endophenotypes of aggression and to assess the contribution of genetic and environmental factors to putative temperamental predictors of these endophenotypes early in life in rhesus macaques. I found that caution in response to a series of novel tasks was negatively associated with aggression in familiar and novel social settings in adult males, indicating that common psychological processes guided impulsive response within disparate conditions. I further found that the experience of early adversity in the form of nursery rearing, combined with alleles of two candidate gene promoter polymorphisms (serotonin transporter and monoamine oxidase A), interacted to predict behavioral inhibition, a temperamental predictor of adult aggression in humans, in infant rhesus macaques. Together, this work demonstrates some of the complex developmental, genetic, and psychological processes that may put individuals at risk for aggressive behavior.
Bibliography: Karere, G.M., Kinnally, E.L, Sanchez, J. N., Famula, T., Lyons, L.A., & Capitanio, J.P. "What is Early Adversity? Monoamine Oxidase A Promoter Polymorphism Variation Influences Infant Response to a Human Intruder in Rhesus Macaques." (Published online ahead of print.) Biological Psychiatry (2008).

Kinnally, E.L., Whiteman, H.J., Mendoza, S.P. & Capitanio, J.P. "Dimensions of Response to Novelty are Associated with Aggression and Social Engagement in Adult Male Rhesus Macaques." Journal of Comparative Psychology 122.2(2008): 195-203.

Kinnally, E.L., Lyons, L.A., Abel, K., Mendoza, S.P. & Capitanio, J.P. "The Effects of Experience and Genotype on Serotonin Transporter Gene Expression in Response to Maternal Separation in Infant Rhesus Macaques." Genes Brain and Behavior 7.4(2008):481-6.