The Neurobiology of Human Social Behavior: A Review of How Testosterone and Cortisol Underpin Competition and Affiliation Dynamics

The brain, behavior, and neuroendocrine system have coevolved to support human group living. Recent developments in behavioral endocrinology over last several decades increasingly point to the powerful role of social experiences in influencing and being influenced by hormones. Here, we review the accumulated empirical developments that link two hormones—testosterone and cortisol—to social competition and affiliation. We suggest that testosterone and cortisol both influence and reflect the dynamics of human social behavior in domains of competition and affiliation, albeit in very different ways. The evidence supports the notion that testosterone may function as a competition hormone that calibrates psychological systems to current social standing and adaptively guide status-seeking efforts. As for cortisol, much evidence reveals that cortisol modulates affiliative behaviors in ways that appear to be adaptive; cortisol is elevated during times of social threat, social isolation, and loneliness, possibly to mobilize responses geared toward seeking coping and support, but is dampened when individuals gain social control and affiliative support. Still, more work is needed to unpack the complex interplay between neurobiology and human sociality. We end with a number of methodological recommendations on how using salivary bioscience methods may ultimately lead to a richer understanding of the complex reciprocal ties between biology and human social behavior.