Sex differences in jealousy: a meta-analytic examination

The theory of evolved sex differences in jealousy predicts sex differences in responses to sexual infidelities and emotional infidelities. Critics have argued that such differences are absent in studies that use continuous measures to assess responses to hypothetical infidelities or in studies that assess responses to real infidelities. These criticisms were tested in two random-effects meta-analyses of 40 published and unpublished papers (providing 209 effect sizes from 47 independent samples) that measured sex differences in jealousy using continuous measures. A significant, theory-supportive sex difference emerged across 45 independent samples using continuous measures of responses to hypothetical infidelities, g*=0.258, 95% confidence interval (CI) [0.188, 0.328], p<.00001. Measured emotion significantly moderated effect size. Effects were strongest when measures assessed distress/upset (g*=0.337) and jealousy (g*=0.309). Other commonly measured negative emotions yielded weaker effects, including hurt (g*=0.161), anger (g*=0.074), and disgust (g*=0.012). Across the 45 independent samples, six significant moderators emerged: random sampling, population type (student vs. nonstudent samples), age, inclusion of a forced-choice question, number of points in the response scale, and year of publication. A significant, theory-supportive effect also emerged across seven studies assessing reactions to actual infidelities, g*=0.234, 95% CI [0.020, 0.448], p=.03. Results demonstrate that the sex difference in jealousy neither is an artifact of response format nor is limited to responses to hypothetical infidelities.