How Hungry is the Selfish Gene?
研究美国和南非继亲家庭中，孩子与父母的经济和基因联系如何影响家庭食物支出，发现非生母抚养的孩子家庭食物支出更少，南非家庭则减少健康食品、增加烟酒消费。
We examine resource allocation in step-households in the United States and South Africa to test whether child investments vary according to economic and genetic bonds between parent and child. In the United States, households spend less on food when a child is raised by a non-biological mother. The reduction is identical for step, adoptive, and foster households, consistent with the hypothesis that genetic ties are the ones that binds. In South Africa, where food spending can be disaggregated, households spend less on milk, fruit and vegetables, and more on tobacco and alcohol, in the absence of a child's birth mother.