Doctoral Dissertation Research: The Social Effects of Male to Female Population Ratios

University Of Utah, Salt Lake City UT

Investigators

Abstract

Doctoral student Emily Stone (University of Utah), with the guidance of Dr. Elizabeth Cashdan, will investigate how variation in the ratio of men per 100 women (adult sex ratio) shapes men's and women's social strategies. Cross-cultural research on the social effects of unequal sex ratios consistently finds a counterintuitive pattern of aggression: men commit more homicides and assaults, a form of male competition over mates, when women outnumber men and mates are plentiful, but competition declines when men outnumber women and mates are less available. This study tests two alternative explanatory hypotheses: a "men's mating opportunities hypothesis," which follows the adage that men are as faithful as their options, and so are competing more when women outnumber them because there are more mating opportunities to go around; and a "female choice hypothesis," which predicts that men are less violent when women are scarce because women have bargaining power in this context and don't find aggression appealing in a mate. The research will be conducted as a natural experiment on two outer islands in Yap state. On one island, men outnumber women, and the other, women outnumber men. The researcher will gather data using multiple methods including behavioral observations, focal follows, semi-structured interviews, and the administration of standardized scales. This research is important for both theory and practice. The logic motivating the men's mating opportunities hypothesis is based on new theoretical models that challenge prominent ideas about what predicts mate competition that have been common for the past 30 years. This study will be one of the first empirical field tests of these new theories. This project also addresses questions about why men choose or do not choose aggressive modes of mate competition; whether and how women also compete over mates; and whether Darwin's ideas about the importance of females in guiding male competition apply to humans. Findings from this research will have application to controlling aggressive behavior in multiple social contexts. Funding this research also supports the education of a social scientist.