Vashro Layne, Padilla Lace, Cashdan Elizabeth
University of Utah, 270 South 1400 East, Salt Lake City, UT, 84112, USA.
Department of Psychology, University of Utah, 380 S 1530 E Beh S 502, Salt Lake City, UT, 84112, USA.
Hum Nat. 2016 Mar;27(1):16-34. doi: 10.1007/s12110-015-9247-2.
The fertility and parental care hypothesis interprets sex differences in some spatial-cognitive tasks as an adaptive mechanism to suppress women's travel. In particular, the hypothesis argues that estrogens constrain travel during key reproductive periods by depressing women's spatial-cognitive ability. Limiting travel reduces exposure to the dangers and caloric costs of navigating long distances into unfamiliar environments. Our study evaluates a collection of predictions drawn from the fertility and parental care hypothesis among the Twe and Himba people living in a remote region of Namibia. We find that nursing mothers travel more than women at any other stage of their reproductive career. This challenges the assumption that women limit travel during vulnerable and energetically demanding reproductive periods. In addition, we join previous studies in identifying a relationship between spatial ability and traveling among men, but not women. If spatial ability does not influence travel, hormonally induced changes in spatial ability cannot be used as a mechanism to reduce travel. Instead, it appears the fitness consequences of men's travel is a more likely target for adaptive explanations of the sex differences in spatial ability, navigation, and range size.
生育与亲代抚育假说将某些空间认知任务中的性别差异解释为一种抑制女性出行的适应性机制。具体而言，该假说认为雌激素通过降低女性的空间认知能力，在关键生殖期限制其出行。限制出行可减少接触进入陌生环境长途导航的危险和热量消耗。我们的研究评估了从生育与亲代抚育假说得出的一系列预测，这些预测针对生活在纳米比亚偏远地区的特维人和辛巴人。我们发现，哺乳期母亲的出行比处于生殖生涯其他任何阶段的女性都多。这对女性在脆弱且精力需求高的生殖期限制出行这一假设提出了挑战。此外，我们与之前的研究一致，发现空间能力与男性的出行之间存在关联，但与女性无关。如果空间能力不影响出行，那么激素诱导的空间能力变化就不能用作减少出行的一种机制。相反，男性出行对适应性的影响似乎更有可能成为对空间能力、导航和活动范围大小方面性别差异进行适应性解释的目标。
