This article tests the effect of environmental risk on parental investment, differentiating between maternal and paternal care. Results indicate that the saturation point of parental investment may be a function of environmental risk, as parental care experiences diminishing returns due to extrinsic risks.

This study examines the relationship between pairbonds and lactation, specifically the relationship between pairbond stability, alloparenting, and cross-cultural trends in breastfeeding. Findings show that both conjugal stability and availability of alloparental care are associated with age at weaning.

This study tests a broad "risk response" hypothesis: environmental risk can reduce parents' involvement and care which, through its effects on children's behavioral strategies later in life, ultimately produces a larger cultural model favoring risky behavior. Examinations of extramarital sex, aggression, theft, and witchcraft support this hypothesis, leading the authors to suggest that child development is the underpinning of cultural adaptation in the face of environmental change.

Possible explanations for human pair-bonding are discussed: provisioning, breastfeeding, alloparenting, subsistence complementarity, and mating competition, male aggression, men’s show-off work, socioecological variation, and child development are all considered. The author does not conduct empirical analyses, but reviews primate comparisons, earlier cross-cultural analyses, and ethnographic case studies.

This study tests three hypotheses on the evolution of the human pair-bond: male-provisioning, male mating competition, and the defense of offspring from other males. Findings indicate that male provisioning and mating competition are factors in the development of the pair-bond. Additional findings indicate that alloparentling, polygyny, and equal contribution to subsistence by each sex contribute to the security of the pair-bond.

This study provides the first tests of the relationships between population-level adolescent fertility rates and mortality risk at two different time points. The hypotheses are based in life-history theory, which predicts that human reproductive choices are shaped by mortality. The authors find that reproductive strategies are significantly predicted by both early (between ages 1-7) risks of mortality and current cues of mortality risk.

In this article, the authors seek to understand dog-human coevolution by considering predictors of different aspects of dog-human relationships across cultures. In order to measure dog-human relationships, the researchers created three indexes: dogs' utility for humans (DUH), humans' utility for dogs (HUD), and the personhood of dogs (PD). Each of these indexes were tested against various pre-coded variables that were empirically and theoretically relevant to this subject.

This article explains the variation in inequality using a model in which a population's inequality depends on the extent to which its most important forms of wealth are transmitted within families across generations. Results suggest that economic systems differ substantially in the intergenerational transmission of wealth.

In this article, the authors reconsider the polygyny threshold model in order to account for the "polygyny paradox." This paradox, as the authors define it, is the trend away from polygyny as societies adopt stratified agricultural economies. This is despite an increase in both the importance of material wealth and greater leaves of wealth inequality both of which would otherwise suggest increased polygyny. The authors develop a new model that does account for this paradox.