London School of Hygiene & Tropical Medicine

Abstract: In recent years there has been much interest regarding the extent to which social relationships are related to various aspects of human wellbeing. The vast majority of studies looking at the interplay between the structure of social relationships and wellbeing have applied social network measures based on interview-derived friendships and social contacts. However, recent advances in the application of bio-loggers in biological studies have made it possible to quantify social relationships based on in-person, rather than perceived, social interactions. Nevertheless, little is known about the degree to which interview-derived and in-person social ties jointly affect health as these two types of social relationships have been considered separately in human studies. In this study, I used interview-derived perceived friendship networks and GPS-derived proximity data in order to determine to what extent perceived and proximity ties are related to physiological stress levels in the Hadza, hunter-gatherers living in North Tanzania. The results of this study show that the overall strength of proximity ties but not network centrality of an individual was positively associated with stress levels among the Hadza. Moreover, although interview-derived friendship networks had no significant effect on stress, individuals who spent more time in close proximity to their nominated best friends experienced significantly lower levels of physiological stress compared to those who had less opportunity to interact with their perceived friends. Overall, the results of my study suggest that the physiological costs related to group living observed in small-scale societies, such as the Hadza, might be mitigated by in-person interactions with perceived friends. This study also highlights the potential advantages of applying an integrated approach in quantifying social network integration in human studies on health by combining measures based on interview-derived and proximity networks.

Bio: Piotr Fedurek is a PhD student at the Department of Life Sciences, University of Roehampton investigating the effects of social integration on physiological stress levels in The Hadza, hunter-gatherers living in Tanzania.