Competition for Cooperation: variability, benefits and heritability of relational wealth in hunter-gatherers.

Many defining human characteristics including theory of mind, culture and language relate to our sociality, and facilitate the formation and maintenance of cooperative relationships. Therefore, deciphering the context in which our sociality evolved is invaluable in understanding what makes us unique as a species. Much work has emphasised group-level competition, such as warfare, in moulding human cooperation and sociality. However, competition and cooperation also occur within groups; and inter-individual differences in sociality have reported fitness implications in numerous non-human taxa. Here we investigate whether differential access to cooperation (relational wealth) is likely to lead to variation in fitness at the individual level among BaYaka hunter-gatherers. Using economic gift games we find that relational wealth: a) displays individual-level variation; b) provides advantages in buffering food risk, and is positively associated with body mass index (BMI) and female fertility; c) is partially heritable. These results highlight that individual-level processes may have been fundamental in the extension of human cooperation beyond small units of related individuals, and in shaping our sociality. Additionally, the findings offer insight in to trends related to human sociality found from research in other fields such as psychology and epidemiology.

Rapidly rising food prices and the experience of food insecurity in urban Ethiopia: impacts on health and well-being.

The rise in food prices since 2007 is widely recognized as signaling a crisis of food insecurity among the world's poor. Scholars sought to chart the impacts of the crisis on food insecurity by conducting simulation studies, assessing anthropometric outcomes, and evaluating shifts in experience-based measures of food security. Few studies, however, have investigated the broader impacts on those most vulnerable and how rapid rises in food prices play out in the everyday lives of those most impacted. We used qualitative methods to investigate the impact of the rise in food prices on the urban poor in Ethiopia. Twenty semi-structured interviews were conducted in August 2011, in the provincial town of Jimma. Themes identified in these interviews included coping strategies, consumption priorities, and impacts on institutional networks of sharing. Our results suggest that several important cultural practices, including funerals and coffee ceremonies, were undermined by the rise in prices, and that respondents linked food prices to increasing food insecurity, which they in turn linked to high levels of stress, poor mental health, and reduced physical health. Our results are consistent with several other studies that suggest that food insecurity has a range of non-nutritional consequences, and that these are due in part to the highly social nature of food. Recognizing the effects of food insecurity on dimensions of everyday life such as interaction with neighbors, and feelings of shame, draws attention to the potential for food price increases to have erosive effects on communal social capital, and to increase the vulnerability of affected peoples to future shocks.