Introduction

The study of hormones has always been linked to the study of social behavior. There is a consensus that modern behavioral endocrinology started with Arnold Berthold's experiments on male chickens, in which he castrated them at a young age and then reimplanted the excised testes in some, noting the effects this had on bodily development and behaviour. At the same time, social neuroendocrinology shares key aspects with behavioral endocrinology. Both disciplines have strong roots in biopsychology and its use of animal models for the experimental study of causal mechanisms in the interactions between hormones, brain, and behavior that would be difficult or impossible to conduct in humans. Both disciplines are interested in how evolutionary forces have shaped continuity and change in hormone-brain-behavior relationships. What sets social neuroendocrinology apart from the more general science of behavioral endocrinology is that social neuroendocrinology studies the relationships that hormones, brain, and behavior have with the social world. The chapter also presents an overview of the key concepts discussed in this book.