Their research tested the theory that couples reduce family sizes as demographic and economic changes cause heavier investment in fewer children (for example, through education and material goods). Such shifts to greater investment in fewer children may first be seen in wealthy families, since this strategy is risky in poor families where the likelihood of child death or ill-health may still be high.
The researchers found that, in both populations, greater wealth is associated with increased biases in child education. In richer families, early born children receive more education than later born children, though early born sons are favored in the patrilineal population and early born daughters in the matrilineal population. Poorer families invest less in their children’s education, but also discriminate less between their offspring. In terms of education, at least, richer parents do seem to be adopting a strategy of investing more in fewer children.
Does Wealth Increase Parental Investment Biases in Child Education? Evidence from Two African Populations on the Cusp of the Fertility Transition by Mhairi A. Gibson and Rebecca Sear in Current Anthropology