Detachment
Most of us find social encounters rewarding, especially when we encounter those with whom we are familiar and have built up a relationship. From an evolutionary point of view, this is not surprising; human beings are fundamentally social organisms, and human development and functioning occur within a social context. The origin of individual differences in the capacity to experience social reward is likely to involve a complex interplay of genetic and environmental variables, including genetic variation, early experience and current situational factors. A few individuals seem to lie at the lower extreme of this continuum, experiencing little or no positive feelings during affiliative interactions. This chapter deals with the psychological and behavioral traits that characterize these uncommon individuals and reviews the mechanisms likely to cause their emotional detachment. The chapter then discusses the importance of aversive early experience in promoting an avoidant style of adult attachment and the role of the brain opioid system and genetic polymorphisms in mediating diminished hedonic response to affiliative interactions.