Physical competition increases testosterone among Amazonian forager-horticulturalists: A test of the 'challenge hypothesis'

Benjamin C. Trumble, Daniel Cummings, Christopher von Rueden, Kathleen A. O'Connor, Eric A. Smith, Michael Gurven, Hillard Kaplan

Research output: Contribution to journalArticlepeer-review

56 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)2907-2912
Number of pages6
JournalProceedings of the Royal Society B: Biological Sciences
Issue number1739
StatePublished - Jul 22 2012
Externally publishedYes


  • Challenge hypothesis
  • Competition
  • Testosterone
  • Tsimane

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Environmental Science(all)
  • Agricultural and Biological Sciences(all)


Dive into the research topics of 'Physical competition increases testosterone among Amazonian forager-horticulturalists: A test of the 'challenge hypothesis''. Together they form a unique fingerprint.

Cite this