title: Flexibility in reproductive timing in human females: integrating ultimate and proximate explanations.
abstract: From an ultimate perspective, the age of onset of female reproduction should be sensitive to variation in mortality rates, and variation in the productivity of non-reproductive activities. In accordance with this prediction, most of the cross-national variation in women's age at first birth can be explained by differences in female life expectancies and incomes. The within-country variation in England shows a similar pattern: women have children younger in neighbourhoods where the expectation of healthy life is shorter and incomes are lower. I consider the proximate mechanisms likely to be involved in producing locally appropriate reproductive decisions. There is evidence suggesting that developmental induction, social learning and contextual evocation may all play a role.
authors.affiliation: Centre for Behaviour and Evolution, Institute of Neuroscience, Newcastle University, UK. daniel.nettle@ncl.ac.uk
authors.forename: Daniel
authors.initials: D
authors.lastname: Nettle
mesh_terms: D004739:England; D005260:Female; D006801:Humans; D008017:Life Expectancy; D008423:Maternal Age; D008954:Models, Biological; D043762:Reproductive Behavior / Q000502:physiology*; D012959:Socioeconomic Factors