The researchers operationalize new measures of Socially Imposed Monogamy (SIM) and Ecologically Imposed Monogamy (EIM) using scores from Murdock's (1986) Ethnographic Atlas in order to reevaluate Alexander et al.'s (1979) findings that sexual stature dimorphism is higher in SIM (monogamous and highly stratified) and polygynous societies compared to EIM (monogamous and egalitarian) ones. The expected associations between marriage system and sexual dimorphism are not robustly significant; however, an interaction effect is discovered between marriage system and stratification with regard to dimorphism.