Social Endocrinology Hormones and Social Motivation

P sychologists have long understood that research on the biological systems of social behavior is critical to our understanding of human social functioning. In his 1967 book titled The Biological Basis of Personality, for example, Hans Eysenck reviewed the extant research on personality and physiology and called for continued research on the topic. Despite the importance that Eysenck placed on biology, biological processes were largely ignored by social and personality psychologists in the following several decades. In recent years, however, psychologists have begun to examine links between biology, personality, and social behavior. As a result, new discoveries about personality and social processes are emerging that could not have emerged with traditional social psychology methods alone. Along with advances in molecular genetics, social neuroscience, and behavioral endocrinology, the potential contributions of biological research to social psychology are greater than they’ve ever been. Social endocrinology is an emerging interdisciplinary field that bridges behavioral endocrinology (the study of the interaction between hormones and behavior) with social and personality psychology. Over a century of animal research has shown that variation in hormone levels influences a variety of social behaviors. For example, testosterone increases aggression and dominance behavior in many species (Giammanco, Tabacchi, Giammanco, Di Majo, & La Guardia, 2005). Testosterone levels also rise during periods of high competition such as the mating season (Wingfield, Hegner, Dufty, & Ball, 1990), and these testosterone rises promote further dominance (Trainor, Bird, & Marler, 2004). Other animal studies show that oxytocin and progesterone promote affiliative behavior, such as parental care, social bonding, and monogamy (Bartz & Hollander, 2006). It has also been well established that glucocorticoids increase during periods of physical and