近日，美国J Pers Soc Psychol杂志发表的一项研究"The financial consequences of too many men: Sex ratio effects on saving, borrowing, and spending"表明，当男女出生比例的失衡，男性数量大于女性时，男人对女人会更大方。
研究人员让参加实验的男人阅读一份报告，报告称男女比例已经严重失调，在未来女人会更少。然后，研究人员让实验者写下他们未来的储蓄计划及负债预期。结果显示，男人们愿意每个月花掉比过去多42%的工资，以及承担比过去多84%的债务。
这项研究的负责人，美国明尼苏达州大学教授Vladas Griskevicius表示，造成这种现象的主要原因在于择偶竞争激烈，使得男人需要更多的金钱投入来获得女人的青睐，这与自然界中雄性之间的竞争是一样的。当动物世界中雌性出生率下降时，雄性往往变得更好斗，因为它们需要更多的竞争去获得交配的机会。而人类与之不同的是，动物们比拼的是体力，而人类则竞争金钱、地位与权力。
接着，研究人员将同样的实验用于女人，结果显示，当女人得知本地区男性比例高于女性时，都期望自己的男友花更多钱用在约会上，比如选择更高级的餐厅等。Griskevicius表示：“当女人意识到自己很抢手时，会希望男人竭尽全力的讨好自己。”
而对此，大多数男人表示认同，他们认为当男性数量大于女性时，自己会比过去更愿意花钱做些浪漫事儿。（生物谷Bioon.com）
doi:10.1037/a0024761
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The financial consequences of too many men: Sex ratio effects on saving, borrowing, and spending
Griskevicius V, Tybur JM, Ackerman JM, Delton AW, Robertson TE, White AE.
The ratio of males to females in a population is an important factor in determining behavior in animals. We propose that sex ratio also has pervasive effects in humans, such as by influencing economic decisions. Using both historical data and experiments, we examined how sex ratio influences saving, borrowing, and spending in the United States. Findings show that male-biased sex ratios (an abundance of men) lead men to discount the future and desire immediate rewards. Male-biased sex ratios decreased men's desire to save for the future and increased their willingness to incur debt for immediate expenditures. Sex ratio appears to influence behavior by increasing the intensity of same-sex competition for mates. Accordingly, a scarcity of women led people to expect men to spend more money during courtship, such as by paying more for engagement rings. These findings demonstrate experimentally that sex ratio influences human decision making in ways consistent with evolutionary biological theory. Implications for sex ratio effects across cultures are discussed.
