Environmental contingency in life history strategies: The influence of mortality and socioeconomic status on reproductive timing.

TLDR

Reproductive timing is predicted to vary with mortality risk and resource availability according to life‑history theory. The study used experimental manipulations of mortality cues to assess their effect on reproductive timing preferences. Mortality cues prompted earlier reproduction among those raised in poverty but delayed it among those raised in wealth, indicating that childhood socioeconomic status moderates the life‑history response to mortality risk.

Abstract

Why do some people have children early, whereas others delay reproduction? By considering the trade-offs between using one's resources for reproduction versus other tasks, the evolutionary framework of life history theory predicts that reproductive timing should be influenced by mortality and resource scarcity. A series of experiments examined how mortality cues influenced the desire to have children sooner rather than later. The effects of mortality depended critically on whether people grew up in a relatively resource-scarce or resource-plentiful environment. For individuals growing up relatively poor, mortality cues produced a desire to reproduce sooner--to want children now, even at the cost of furthering one's education or career. Conversely, for individuals growing up relatively wealthy, mortality cues produced a desire to delay reproduction--to further one's education or career before starting a family. Overall, mortality cues appear to shift individuals into different life history strategies as a function of childhood socioeconomic status, suggesting important implications for how environmental factors can influence fertility and family size.