Marriage Markets and Male Mating Effort: Violence and Crime Are Elevated Where Men Are Rare

Abstract

The negative social outcomes in populations with male-biased sex ratios are a growing concern. In general, the expectation is of heightened violence as a result of excess men engaging in antisocial behavior and crime, thereby threatening societal stability. While intuitive, these claims are largely unsupported in the literature. Using mating market theory as our guide, we examine indicators of male mating effort, including (1) violent competition between men (homicide, aggravated assault) and (2) indicators of uncommitted sexual behavior (rape, sex offenses, and prostitution). Our unit of analysis is U.S. county-level data. We find that counties with more men have lower rates of crime and violent behavior. Our findings challenge conventional claims of male excess leading to elevated levels of violence. Instead, in support of mating market predictions, we find that criminal and violent behavior related to male mating effort is least common in male-biased sex ratios. We discuss the implications of our findings for public policy regarding incarceration and criminal behavior.

The potential pitfalls of studying adult sex ratios at aggregate levels in humans

“…[43,77]) for most of our analyses, but other operationalizations are perhaps somewhat narrower (e.g. 15-45 as used in [47] or 15 -49 in [72]) and better map on to 'operational sex ratio'. Worrisome for this area of research is that sex ratios might only correlate moderately with each other when using different age cut-offs (see [126] for a discussion with US census data).…”

Not all sex ratios are equal: the Fisher condition, parental care and sexual selection

“…In addition, recent phylogenetic comparative analyses in shorebirds show that the ASR is correlated with breeding system evolution (Liker et al 2013), divorce rates (Liker et al 2014), and sex differences in parental care (Liker et al 2015); and studies of humans link the ASR to mating competition, dispersal patterns, and parental care (e.g. Schacht & Borgerhoff Mulder 2015;Schacht et al 2016;Kramer et al this volume;Schacht & Smith, this volume;Uggla & Mace, this volume). Finally, we ask what data we need to test sex role models (see §7).…”

Does Adult Sex Ratio Predict Regional Variation in Facial Dominance Perceptions? Evidence From an Analysis of U.S. States

“…By contrast with previous assumptions, recent research suggests that direct (i.e., violent) competition among men is greater in geographic regions where the adult sex ratio of the local population is more female biased (Schacht, Rauch, & Mulder, 2014;Schacht, Tharp, & Smith, 2016). This relationship is thought to occur because the rarer sex, having greater "market value," is better positioned to pursue their sextypical optimal mating strategy (Pollet & Nettle, 2008).…”