Religious parents receive more alloparental aid in rural Bangladesh.

Researchers have long speculated about the evolutionary benefits of religiosity. One explanation for the evolution of religious ritual is that rituals signal commitment to co-religionists. As a major domain of prosocial behaviour, alloparental care - or care directed at children by non-parents - is a plausible benefit of religious signalling. The religious alloparenting hypothesis posits that parents who signal religious commitment receive greater alloparental support. Prior research on religiosity, cooperation, and allocare tends to treat individuals as isolated units, despite the inherent collective nature of religious cooperation. Here, we address this limitation in a survey-based study of 710 parents in rural Bangladesh. Instead of focusing only on mothers, we consider the interplay between both mothers and fathers in eliciting allocare, and leverage variation in the covertness of religious rituals to test a key mechanistic assumption linking religious ritual with cooperation. We find that parents who practice religious rituals more frequently receive greater alloparental support from co-religionists. This effect is moderated by parent gender, as well as variation in the visibility of religious rituals. Women's private practices positively affect only those alloparents with whom they share a household, whereas men's public practices positively affect alloparents more broadly.