Stephen John Suomi, Ph.D.

Senior Investigator

Laboratory of Comparative Ethology


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Research Topics

Genetic and Environmental Determinants of Primate Biobehavioral Development

Our research involves broad-based investigations of primate biological and behavioral development through comparative longitudinal studies of rhesus monkeys and other primates. Our primary goals are to characterize distinctive biobehavioral phenotypes in our rhesus monkey colony, to determine how genetic and environmental factors interact to shape the developmental trajectories of each phenotype, and to assess the long-term behavioral and biological consequences for monkeys from various genetic backgrounds when they are reared in different physical and social environments. A second major program of research investigates how rhesus monkeys and other non-human primate species born and raised under different laboratory conditions adapt to placement into environments that model specific features of their natural habitat.


Stephen J. Suomi, Ph.D. is Chief of the Laboratory of Comparative Ethology in NICHD. He holds research professorships at the University of Virginia, the University of Maryland, College Park, the Johns Hopkins University, Georgetown University, the Pennsylvania State University, and the University of Maryland, Baltimore County. Dr. Suomi earned his B.A. in psychology at Stanford University in 1968, and his M.A. and Ph.D. in psychology at the University of Wisconsin-Madison in 1969 and 1971, respectively. He then joined the Psychology faculty at the University of Wisconsin-Madison, where he eventually attained the rank of Professor before moving to the NICHD in 1983.

Dr. Suomi’s initial postdoctoral research successfully reversed the adverse effects of early social isolation, previously thought to be permanent, in rhesus monkeys. His subsequent research at Wisconsin led to his election as Fellow in the American Association for the Advancement of Science “for major contributions to the understanding of social factors that influence the psychological development of nonhuman primates.” His present research at NICHD focuses on three general issues: the interaction between genetic and environmental factors in shaping individual developmental trajectories, the issue of continuity vs. change and the relative stability of individual differences throughout development, and the degree to which findings from monkeys studied in captivity generalize not only to monkeys living in the wild but also to humans living in different cultures.

Throughout his professional career Dr. Suomi has been the recipient of numerous awards and honors, the most recent of which include the Donald O. Hebb Award from the American Psychological Association, the Distinguished Primatologist Award from the American Society of Primatologists, and the Arnold Pfeffer Prize from the International Society of Neuropsychoanalysis. To date, he has authored or co-authored over 400 articles published in scientific journals and chapters in edited volumes.

Selected Publications

  1. Massart R, Suderman MJ, Nemoda Z, Sutti S, Ruggiero AM, Dettmer AM, Suomi SJ, Szyf M. The Signature of Maternal Social Rank in Placenta Deoxyribonucleic Acid Methylation Profiles in Rhesus Monkeys. Child Dev. 2017;88(3):900-918.

  2. Dettmer AM, Novak MF, Novak MA, Meyer JS, Suomi SJ. Hair cortisol predicts object permanence performance in infant rhesus macaques (Macaca mulatta). Dev Psychobiol. 2009;51(8):706-13.

  3. Ferrari PF, Paukner A, Ionica C, Suomi SJ. Reciprocal face-to-face communication between rhesus macaque mothers and their newborn infants. Curr Biol. 2009;19(20):1768-72.

  4. Paukner A, Suomi SJ, Visalberghi E, Ferrari PF. Capuchin monkeys display affiliation toward humans who imitate them. Science. 2009;325(5942):880-3.

  5. Dettmer AM, Murphy AM, Guitarra D, Slonecker E, Suomi SJ, Rosenberg KL, Novak MA, Meyer JS, Hinde K. Cortisol in Neonatal Mother's Milk Predicts Later Infant Social and Cognitive Functioning in Rhesus Monkeys. Child Dev. 2017.

This page was last updated on July 12th, 2017