Marriage markets and mating aggression help explain societal differences in violent crime

Violent crimes (murders, rapes, and assaults) are higher in countries with a relative scarcity of men according to research using both United Nations and INTERPOL data and controlling for economic development, income inequality, urbanization, population density, police presence, and drug trafficking (Barber, 2009a). This is an apparent contradiction given that males are more criminally violent and I argue that the most plausible explanation is that there is more direct mating effort, and hence more violent crime, in countries having a relative scarcity of men (or a low sex ratio). Alternative explanations that are discussed and found wanting include cultural determinism. Causal links connecting the marriage market and violent crime include possible sociological, physiological, and developmental mechanisms that offer exciting prospects for future researchers.

Research Highlights► Societal differences in sexual, reproductive behavior, crime, religion. ► Marriage markets and sex ratios. ► Formulated Evolutionary Social Science. ► Recent books: Kindness in a Cruel World, The Myth of Culture. ► Blogs at Psychology Today and Huffington Post.