Although animal researchers established the role of testosterone as a 'social hormone' decades ago, the investigation of its causal influence on human social behaviors has only recently begun. Here, we review and discuss recent studies showing the causal effects of testosterone on social interactions in animals and humans, and outline the basic neurobiological mechanisms that might underlie these effects. Based on these recent findings, we argue that the role of testosterone in human social behavior might be best understood in terms of the search for, and maintenance of, social status.
Testosterone in contextTestosterone is one of the major sex hormones produced by the body, occurring in both men and women. In men, it is mainly produced by the Leydig cells of the testes, whereas the ovaries and placenta produce it in women. The adrenal cortex also secretes it in both sexes [1]. Testosterone has a well-known and important role in the development of secondary sexual attributes; for example, increased muscle, bone mass and body hair in men. However, it is also of special interest in the study of socio-emotional and economic behavior because it influences the brain in archetypical situations, such as fight, flight, mating and the search and struggle for status [2].Three recent developments argue for a causal role of testosterone as a 'social' hormone. First, recent years have seen the advent of acute single-dose testosterone administration studies in humans. This methodological innovation is important because it enables the study of the effect of testosterone on complex social interactions between human subjects, rather than its impact on the more difficult to interpret behavioral repertoire of non-human animals. Moreover, testosterone administration studies can establish the causality of testosterone in facilitating particular motives and behaviors.Second, the advent of sophisticated behavioral paradigms allows for the study of social emotional processes, such as threat vigilance, and affiliative behaviors, such as facial mimicry, emotion inference and trust. These paradigms not only make it possible to assess whether the hormone plays a role in modulating behavior, but also add to the understanding of the motives that might underlie human interactions. Third, the integration of experimental economic paradigms into the study of hormonal effects on behavior provides an opportunity to identify the precise channels through which testosterone affects social interaction in a controlled laboratory environment.Together, these advances offer an exciting new opportunity to reassess the role of testosterone in driving behavior. Here, we summarize recent evidence using these approaches and argue that the role of testosterone in social interaction in humans might be best conceptualized as bringing motives for seeking social status to the fore. We also discuss the psychological and neurobiological channels that might underlie these effects.Animal models of the role of testosterone in social interactions Early evidence for the r...