Cooperation in Polygynous Households: Experimental Evidence from Northern Benin

In the literature, polygyny is frequently associated with intrahousehold inefficiencies, commonly attributed to a lack of cooperation between co-wives. In this paper, we challenge this claim by investigating the extent to which co-wives are inclined to cooperate when mutual gains are at stake. Additionally, we examine whether the lack of voice in intrahousehold decision-making contributes to explaining the commonly observed inefficiencies. Using public good games in northern Benin, we find that co-wives are not more likely to cooperate with their husband than with one another. Moreover, when they share mutual interests, they tend to coalesce and act against their husband’s interests. These findings are particularly strong among women with low levels of agency. We argue that co-wives with low agency have greater incentive to unite in order to collectively improve their access to household resources, because individually they are marginalized. Finally, the comparison between monogamous and polygynous households reveals that efficiency levels and the determinants of cooperative behavior are similar in both types of households (at least when household members themselves set the rules regarding the allocation of the public good).