The Sex Ratio as a Predictor of Cross-National Variation in Violent Crime

Abstract

Because low-sex-ratio societies are likely to have increased family conflict, and because family conflict increases aggression, it was predicted that these societies would have higher rates of violent crimes such as homicide, rape, and assaults. These predictions were supported in regression analyses of Interpol data for 70 countries that used a variety of controls for level of economic development, ecology (mean temperature, population density, population movement), marriage system, and geographical region. The results indicate that family variables can account for a substantial amount of the crossnational variance in violent crime.

Inequality and risk-taking behaviour

“…Further, while the underlying causation for these differing customs may be economic, such institutions change slowly and most individuals would plausibly take them as fixed. Indeed, broadly consistent with the hypotheses advanced here, existing cross-cultural studies (Bacon et al, 1963;Barber, 2000) find that polygamy is associated with higher levels of violent crime. More recently, Wei and Zhang (2011) find that more risk-taking behaviour is to be found in provinces in China where the male-female gender ratio is high and thus marriage opportunities for males are more fiercely competed.…”

Too many men: the violence problem?

“…Likewise, 'tough on crime' policies that incarcerate increasing numbers of men might be contributing to higher rates of violence, rather than alleviating them, through the resulting sex ratio imbalance in highly policed communities (e.g., [54]). Similarly appeals to abolish polygyny because of the dangerous emergence of a class of unmarried men rely on equally flawed logic [7], especially given the evidence that rates of rape, sexual assault [42,43], and male-male homicide [55] are lower where men are in excess. In short, the 'more men more violence' expectation derives from a simplistic interpretation of Trivers' original paper and a failure to appreciate more recent theoretical developments.…”

“…and sexual assault [42,43]. However, several USA studies looking to intimate partner violence and female homicide victimization found more violence directed against women by their partners when men were in excess [44][45][46].…”

Violence, Teenage Pregnancy, and Life History

“…An increase in population density (especially in an area of already limited resource) exacerbates these stress levels, as competition increases. A negative sex-ratio is also associated with family breakdown (Guttentag & Secord, 1983;Barber, 2000aBarber, , 2000b. When women are abundant, men find it easy to move from mate to mate, reducing parental investment in offspring, increasing the number of female-headed households and implicitly conveying to children that monogamy and paternal provision are not expectable.…”

“…South and Messner (1987) showed that an excess of women increases female crime rates. Barber (2000a) demonstrated cross-culturally that low sex ratios predicted higher homicide levels. Messner and Sampson (1991) reached similar conclusions examining 153 American cities.…”