Currently much debate surrounds the significance of cross-cultural variation in mother-infant attachment. Is only one form of attachment “healthy,” or are different types of attachment adaptations to local socioecological conditions? Juvenile mortality rates have been promoted as important features of local environments that shape attachment, which in turn affects later reproductive strategies. To this we add fertility. Fertility changes the environment of a child by influencing the number of potential caregivers and competitors for care, and the cultural ethos regarding the (...) rights of children. Different combinations of fertility and mortality will likely give rise to different attachment forms, and only under one regime (low fertility and mortality) do we expect exclusivity in attachment. (shrink)