Cross-National Variation in the Motivation for Uncommitted Sex: The Role of Disease and Social Risks

Abstract

Evolutionary psychological meta-theory predicts that interest in “casual” sex should decline with its costs (e.g., acquiring HIV/AIDS or an infectious disease, unwanted pregnancy, loss of spousal commitment). Analyses of Schmitt's (2005) data on sociosexuality in 48 countries (including gender differences therein) tested these predictions using multiple regressions controlling for economic development and population density. Sociosexuality declined as HIV/AIDS increased and as teen births increased, supporting the hypothesis, but female sociosexuality increased with the risk of infectious disease. Sociosexuality was lower in countries in which there was a greater proportion of men in the population and marriages likely involved greater commitment. Country differences in sexual motivation partly reflect varying costs of extramarital sexuality with females possibly increasing their interest in sexual variety to boost heritable disease resistance.