Paternity confidence and social obligations explain men's allocations to romantic partners in an experimental giving game

Paternal care in humans is facultative, with investment decisions responsive to socioecological context. In particular, paternity confidence is thought to have a significant impact on men's provisioning. However, various aspects of the relationship a man has with his partner can also influence the way he provides for his children. Previous papers have tended to focus either on these kinds of relationship dynamics or on the impact of paternity confidence. However, these categories are often intertwined and parsing their contributions can be conceptually and methodologically difficult. To better understand how paternity confidence and relationship dynamics impact men's investment decisions, we used a series of pictorial vignettes to assess the resource allocation strategies of Himba men. We focus on three traits: mate fidelity, partner type (marital or non-marital), and relationship status (current or former). Results suggest that men prioritize mate fidelity and current reproductive partners in investment decisions, but social obligations to past and current partners and the presence of other male investors also influence decisions. Himba men appear to be balancing social norms related to marriage and fatherhood with individually-driven incentives to invest in current and more faithful partners.