Children pose a problem. The extended period of childhood dependency and short inter-birth intervals mean that human mothers have to care for several dependent children simultaneously. It has long been argued that this is too much of an energetic burden for mothers to manage alone, and that they must enlist help from other relatives to share the costs of raising children. Which kin help is the subject of much debate. Here, we review the evidence for whether the presence of kin affects child survival rates, in order to infer whether mothers do receive help in raising offspring and who provides this help. These 45 studies come from a variety of (mostly) natural fertility populations, both historical and contemporary, across a wide geographical range. We find that in almost all studies, at least one relative (apart from the mother) does improve the survival rates of children, but that relatives differ in whether they are consistently beneficial to children or not. Maternal grandmothers tend to improve child survival rates, as do potential sibling helpers at the nest (though the latter observation is based on rather few studies). Paternal grandmothers show somewhat more variation in their effects on child survival. Fathers have surprisingly little effect on child survival, with only a third of studies showing any beneficial effects. Overall, this review suggests that while help from kin may be a universal feature of human childrearing, who helps is dependent on ecological conditions.

P o P u l at i o n a n d d e v e l o P m e n t r e v i e w 3 7 ( S u P P l e m e n t ) : 8 1 -1 1 2 ( 2 0 1 1 ) 8 1

Small-scale human societies range from foraging bands with a strong egalitarian ethos to more economically stratified agrarian and pastoral societies. We explain this variation in inequality using a dynamic model in which a population’s long-run steady-state level of inequality depends on the extent to which its most important forms of wealth are transmitted within families across generations. We estimate the degree of intergenerational transmission of three different types of wealth (material, embodied, and relational) as well as the extent of wealth inequality in 21 historical and contemporary populations. We show that intergenerational transmission of wealth and wealth inequality are substantial among pastoral and small-scale agricultural societies (on a par with or even exceeding the most unequal modern industrial economies) and quite limited among horticultural and foraging peoples (equivalent to the most egalitarian of modern industrial populations). Differences in the technology by which a people derive their livelihood and in the institutions and norms making up the economic system jointly contribute to this pattern.

Hypotheses for the evolution of human female life-history characteristics have often focused on the social nature of human societies, which allows women to share the burden of childcare and provisioning amongst other members of their kin group. We test the hypothesis that child health and survival probabilities will be improved by the presence of kin using a longitudinal database from rural Gambia. We find that the only kin to improve the nutritional status of children significantly (apart from mothers) are maternal grandmothers, and that this is reflected in higher survival probabilities for children with living maternal grandmothers. There is also evidence that the reproductive status of the maternal grandmother influences child nutrition, with young children being taller in the presence of non-reproductive grandmothers than grandmothers who are still reproductively active. Paternal grandmothers and male kin, including fathers, have negligible impacts on the nutritional status and survival of children.

This is an electronic version of an Article published in Demography, 39 (1). pp. 43-63