Department of Anthropology, University of Washington, , Seattle, WA 98195, USA.
Proc Biol Sci. 2012 Jul 22;279(1739):2907-12. doi: 10.1098/rspb.2012.0455. Epub 2012 Mar 28.
The challenge hypothesis posits that acute increases in testosterone (T) during male-male competition enhance performance and survivability while limiting the physiological costs of consistently high T. Human challenge hypothesis research focuses on young men in industrial populations, who have higher baseline T levels than men in subsistence populations. We tested whether the Tsimane, pathogenically stressed forager-horticulturalists of the Bolivian Amazon, would express acute T increases in response to physical competition. Saliva was collected from 88 Tsimane men (aged 16-59 years) before and after a competitive soccer match. Tsimane men had significantly lower baseline levels of T (β = -0.41, p < 0.001) when compared with age-matched United States (US) males. Linear mixed-effects models were used to establish that T increased significantly immediately following competition (β = 0.23, p < 0.001), remaining high 1 h later (β = 0.09, p = 0.007); equivalent to 30.1 and 15.5 per cent increases in T, respectively. We did not find larger increases in T among winners (p = 0.412), although T increases were positively associated with self-rated performance (β = 9.07, p = 0.004). These results suggest that despite lower levels of T than US males, Tsimane males exhibit acute increases in T at the same relative magnitude reported by studies in industrialized settings, with larger increases in T for those who report better individual performance.
挑战假说认为，雄性间竞争时睾丸酮（T）的急性增加可以提高表现能力和生存能力，同时限制 T 持续升高的生理成本。人类挑战假说的研究集中在工业人群中的年轻男性，他们的基础 T 水平高于自给自足人群中的男性。我们测试了玻利维亚亚马逊地区的 Tsimane 觅食者-园艺人群是否会对身体竞争做出急性 T 增加的反应，他们受到病原体的压力。在一场竞争性足球比赛前后，我们从 88 名 Tsimane 男性（年龄在 16-59 岁之间）中采集了唾液。与年龄匹配的美国男性相比，Tsimane 男性的 T 基础水平明显较低（β=-0.41，p<0.001）。线性混合效应模型表明，T 在比赛后立即显著增加（β=0.23，p<0.001），1 小时后仍保持较高水平（β=0.09，p=0.007）；分别相当于 T 增加了 30.1%和 15.5%。我们没有发现胜利者的 T 增加更大（p=0.412），尽管 T 的增加与自我评估的表现呈正相关（β=9.07，p=0.004）。这些结果表明，尽管 Tsimane 男性的 T 水平低于美国男性，但他们表现出与工业化环境中研究报告的相对幅度相同的急性 T 增加，而那些报告个人表现更好的人 T 增加幅度更大。
