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

博士生艾米丽·斯通（犹他大学）将在伊丽莎白·卡什丹博士的指导下，研究男女比例（成人性别比例）的变化如何影响男性和女性的社交策略。关于性别比例不平等的社会影响的跨文化研究一直发现一种违反直觉的攻击模式：当女性数量超过男性、伴侣数量充足时，男性会犯下更多的杀人和攻击行为，这是一种男性对伴侣的竞争，但当男性数量超过女性、伴侣数量减少时，竞争就会减弱。这项研究检验了两种可供选择的解释假说：一种是“男性的交配机会假说”，该假说遵循的格言是，男性的忠诚程度与他们的选择一样高，因此当女性数量超过他们时，他们会更积极地竞争，因为有更多的交配机会；还有一个“女性选择假说”，该假说预测，当女性稀缺时，男性的暴力倾向会降低，因为在这种情况下，女性有讨价还价的能力，不会觉得伴侣有攻击性。该研究将作为自然实验在雅浦州的两个外岛进行。在一个岛上，男人多于女人，在另一个岛上，女人多于男人。研究人员将使用多种方法收集数据，包括行为观察、焦点跟踪、半结构化访谈和标准化量表的管理。本研究具有重要的理论和实践意义。推动男性择偶机会假说的逻辑是基于新的理论模型，这些模型挑战了过去30年来普遍存在的关于如何预测配偶竞争的突出观点。这项研究将是这些新理论的第一个实证现场测试之一。这个项目也解决了为什么男人选择或不选择侵略性的配偶竞争模式的问题；女性是否以及如何竞争配偶；以及达尔文关于女性在指导男性竞争中的重要性的观点是否适用于人类。本研究结果将应用于多种社会情境下的攻击行为控制。资助这项研究也支持了社会科学家的教育。

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.