Human male pair bonding and testosterone

Previous research in North America has supported the view that male involvement in committed, romantic relationships is associated with lower testosterone (T) levels. Here, we test the prediction that undergraduate men involved in committed, romantic relationships (paired) will have lower T levels than men not involved in such relationships (unpaired). Further, we also test whether these differences are more apparent in samples collected later, rather than earlier, in the day. For this study, 107 undergraduate men filled out a questionnaire and collected one saliva sample (from which a subject’s T level was measured) at various times across the day. As in previous studies, men involved in committed, romantic relationships had lower salivary T levels, though only during later times of the day. Furthermore, additional analysis of the variation among unpaired subjects indicated that men without prior relationship experience had lower T levels than experienced men. Finally, while paired men as a group had lower T levels than unpaired men, those men at the earliest stage (less than six months) of a current relationship had higher T levels than unpaired men as well as men in longer-term relationships. These results suggest that variation in male testosterone levels may reflect differential behavioral allocation to mating effort. Peter Gray recently completed his Ph.D. in biological anthropology at Harvard with a dissertation entitled, "Human Male Reproductive Strategies: Cross-Cultural and Endocrine Aspects." He is now a postdoctoral fellow at Charles Drew University of Medicine and Science, working with Dr. Shalender Bhasin on human androgen research. Judith Flynn Chapman and Matthew McIntyre are Ph.D. candidates inbiological anthropology at Harvard University. Judith Flynn Chapman focuses on variation in human ovarian function. Matthew McIntyre studies the role of testosterone in psychological development. Terry Burnham is an economist at the Harvard Business School. He studies economic behavior in a framework based in evolution by natural selection. Susan Lipson is a Lecturer in Anthropology and director of the Reproductive Ecology Laboratory at Harvard University. Her research includes work on the effects of age and energy balance on female reproductive function, and on hormonal correlates of conception and cancer risk. Peter Ellison is John Cowles Professor of Anthropology and Dean of the Graduate School of Arts and Sciences at Harvard University. He studies hormones, behavior, and the reproductive ecology of humans and nonhuman primates.