Partner choice in human evolution: The role of cooperation, foraging ability, and culture in Hadza campmate preferences

Abstract

The ability to choose the partners we interact with is thought to have been an important driver in the evolution of human social behavior, and in particular, our propensity to cooperate. Studies showing that humans prefer to interact with cooperative others is often cited as support for partner choice driving the evolution of cooperation. However, these studies are largely drawn from Western samples, where conditions for partner choice to operate may be especially favorable. Here, we investigate qualities associated with being a preferred partner (i.e., campmate) in Hadza hunter-gatherers of Tanzania in 2016 and 2019. A total of 156 Hadza participants from 17 camps ranked their campmates on generosity, foraging ability, and their preference for them as future campmates. In 2016, Hadza preferred more generous people and better hunters as campmates, with evidence suggesting a stronger preference for better hunters; however, the relationship between generosity and being a preferred campmate was greater in 2019 than in 2016, such that the preference for generous people was stronger than the preference for better foragers, suggesting that campmate preferences are changing. These new findings contrast with reports on data from nearly a decade ago, suggesting that the Hadza do not prefer more cooperative campmates. Further, in 2019, there was anecdotal evidence that Hadza with greater exposure to outside cultural institutions (e.g., schooling, having a job, or living in a village) had a stronger preference for generous campmates than those with less exposure. Taken together, the results suggest that preferences for social partners may, in part, be culturally shaped.

Hadza Hunter-Gatherers Disagree on Perceptions of Moral Character

“…These results further support recent research finding that character and moral reputation do not play a role in Hadza campmate preferences. When asked who they prefer to live with, Hadza do not choose the most generous people, whether generosity is measured using an economic game (Apicella, Marlowe, Fowler, & Christakis, 2012) or via reputation (Smith & Apicella, 2019). Rather, Hadza prefer to live with better hunters (Smith & Apicella, 2019; Wood, 2006).…”

“…When asked who they prefer to live with, Hadza do not choose the most generous people, whether generosity is measured using an economic game (Apicella, Marlowe, Fowler, & Christakis, 2012) or via reputation (Smith & Apicella, 2019). Rather, Hadza prefer to live with better hunters (Smith & Apicella, 2019; Wood, 2006). If moral behavior changes across time and situations as our results here suggest, then choosing campmates based on their current behavior is useless.…”

The benefits of being seen to help others: indirect reciprocity and reputation-based partner choice

“…Furthermore, competition for partners leads individuals to share honest gossip about others [96]. There is evidence that generosity is displayed publicly [97], but whether individuals do choose the most cooperative others as alliance partners seems context dependent [98]. In fact the prediction that individuals will ostentatiously display higher generosity is simplistic, because it may then be apparent that the helper is motivated by strategic gains rather than a cooperative disposition.…”

A Cultural Species and its Cognitive Phenotypes: Implications for Philosophy

“…It's the people in Chicago who are peculiar when placed in a global and historical perspective. A wide range of other evidence, much of it collected since Miller's early work, confirms that WEIRD people are particularly inclined toward dispositional inferences (Chiu et al 2000;Heine 2016;Nisbett 2003;Smith and Apicella 2020). The centrality of dispositions in the social sciences, using acontextual traits like 'extroverted', 'inequality averse,' or 'moral', reflect WEIRD biases in thinking.…”