This project will examine the physiological processes involved in maintaining relationships in large scale communities (i.e. beyond the 150-level community of the personal network). In traditional small scale societies, communities are bonded through a variety of activities as diverse as music and dance, and the rituals of religion, often associated with a form of euphoria that Durkheim referred to as “effervescence”. This project will seek to test the hypothesis that, at both the dyadic level and the community level, it is beta-endorphins that underpin social bonding. In previous studies, we have found prima facie evidence that endorphins are involved in several candidate activities (notably laughter and music). In the context of relationships at the community level, synchronised co-action in groups seems to play a particularly important role. However, we also want to take this approach beyond the “normal” scale of personalised relationships to ask whether and how these same mechanisms are used to create a sense of community membership on the very large scale – in effect, allowing us to turn complete strangers into friends.