{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T00:13:10Z","timestamp":1792627990027,"version":"4.5.0"},"reference-count":81,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2020,1,15]],"date-time":"2020-01-15T00:00:00Z","timestamp":1579046400000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2020,1,15]],"date-time":"2020-01-15T00:00:00Z","timestamp":1579046400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Sci Rep"],"abstract":"<jats:title>Abstract<\/jats:title><jats:p>The Male Warrior Hypothesis (MWH) establishes that men\u2019s psychology has been shaped by inter-group competition to acquire and protect reproductive resources. In this context, sex-specific selective pressures would have favored cooperation with the members of one\u2019s group in combination with hostility towards outsiders. We investigate the role of developmental testosterone, as measured indirectly through static markers of prenatal testosterone (2D:4D digit ratio) and pubertal testosterone (body musculature and facial masculinity), on both cooperation and aggressive behavior in the context of intergroup conflict among men. Supporting the MWH, our results show that the intergroup conflict scenario promotes cooperation within group members and aggression toward outgroup members. Regarding the hormonal underpinnings of this phenomenon, we find that body musculature is positively associated with aggression and cooperation, but only for cooperation when context (inter-group competition) is taken into account. Finally, we did not find evidence that the formidability of the group affected individual rates of aggression or cooperation, controlling for individual characteristics.<\/jats:p>","DOI":"10.1038\/s41598-019-57259-0","type":"journal-article","created":{"date-parts":[[2020,1,15]],"date-time":"2020-01-15T11:03:00Z","timestamp":1579086180000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":31,"title":["The Male Warrior Hypothesis: Testosterone-related Cooperation and Aggression in the Context of Intergroup Conflict"],"prefix":"10.1038","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6275-8456","authenticated-orcid":false,"given":"J. A.","family":"Mu\u00f1oz-Reyes","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P.","family":"Polo","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"N.","family":"Valenzuela","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"P.","family":"Pavez","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"O.","family":"Ram\u00edrez-Herrera","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"O.","family":"Figueroa","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"C.","family":"Rodriguez-Sickert","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7149-0535","authenticated-orcid":false,"given":"D.","family":"D\u00edaz","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"M.","family":"Pita","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2020,1,15]]},"reference":[{"key":"57259_CR1","doi-asserted-by":"crossref","unstructured":"Bowles, S. & Gintis, H. A cooperative species: Human reciprocity and its evolution. 262 (Princeton University Press, 2011).","DOI":"10.1515\/9781400838837"},{"key":"57259_CR2","doi-asserted-by":"publisher","first-page":"326","DOI":"10.1038\/456326a","volume":"456","author":"S Bowles","year":"2008","unstructured":"Bowles, S. Being human: Conflict: Altruism\u2019s midwife. Nature 456, 326\u2013327 (2008).","journal-title":"Nature"},{"key":"57259_CR3","doi-asserted-by":"publisher","first-page":"405","DOI":"10.1111\/j.1467-9280.2008.02100.x","volume":"19","author":"N Halevy","year":"2008","unstructured":"Halevy, N., Bornstein, G. & Sagiv, L. \u201cIn-group love\u201d and \u201cout-group hate\u201d as motives for individual participation in intergroup conflict: A new game paradigm. Psychol. Sci. 19, 405\u2013411 (2008).","journal-title":"Psychol. Sci."},{"key":"57259_CR4","doi-asserted-by":"publisher","first-page":"394","DOI":"10.1038\/nature16477","volume":"529","author":"MM Lahr","year":"2016","unstructured":"Lahr, M. M. et al. Inter-group violence among early Holocene hunter-gatherers of West Turkana, Kenya. Nature 529, 394\u2013398 (2016).","journal-title":"Nature"},{"key":"57259_CR5","doi-asserted-by":"publisher","first-page":"985","DOI":"10.1126\/science.239.4843.985","volume":"239","author":"NA Chagnon","year":"1988","unstructured":"Chagnon, N. A. Life histories, blood revenge, and warfare in a tribal population. Science 239, 985\u2013992 (1988).","journal-title":"Science"},{"key":"57259_CR6","doi-asserted-by":"publisher","first-page":"249","DOI":"10.1017\/S0140525X09990951","volume":"32","author":"J Archer","year":"2009","unstructured":"Archer, J. Does sexual selection explain human sex differences in aggression? Behav. Brain Sci. 32, 249\u2013266 (2009).","journal-title":"Behav. Brain Sci."},{"key":"57259_CR7","unstructured":"Brown, D. E. Human universals. (McGraw-Hill New York, 1991)."},{"key":"57259_CR8","doi-asserted-by":"publisher","first-page":"670","DOI":"10.1098\/rstb.2011.0301","volume":"367","author":"MM McDonald","year":"2012","unstructured":"McDonald, M. M., Navarrete, C. D. & Van Vugt, M. Evolution and the psychology of intergroup conflict: the male warrior hypothesis. Philos. Trans. R. Soc. Lond., Ser. B: Biol. Sci. 367, 670\u2013679 (2012).","journal-title":"Philos. Trans. R. Soc. Lond., Ser. B: Biol. Sci."},{"key":"57259_CR9","doi-asserted-by":"publisher","first-page":"263","DOI":"10.1016\/j.tics.2011.04.008","volume":"15","author":"C Eisenegger","year":"2011","unstructured":"Eisenegger, C., Haushofer, J. & Fehr, E. The role of testosterone in social interaction. Trends Cogn. Sci. 15, 263\u2013271 (2011).","journal-title":"Trends Cogn. Sci."},{"key":"57259_CR10","doi-asserted-by":"publisher","first-page":"309","DOI":"10.1016\/j.evolhumbehav.2011.10.008","volume":"33","author":"L Betzig","year":"2012","unstructured":"Betzig, L. Means, variances, and ranges in reproductive success: comparative evidence. Evol. Hum. Behav. 33, 309\u2013317 (2012).","journal-title":"Evol. Hum. Behav."},{"key":"57259_CR11","doi-asserted-by":"publisher","first-page":"1294","DOI":"10.1126\/science.206.4424.1294","volume":"206","author":"N Howell","year":"1979","unstructured":"Howell, N. Sociobiological Hypotheses Explored. Science 206, 1294\u20131295 (1979).","journal-title":"Science"},{"key":"57259_CR12","unstructured":"Trivers, R. In Sexual selection and the descent of man 1871\u20131971 (ed Bernard Campbell) 136\u2013179 (Aldine-Atherton, 1972)."},{"key":"57259_CR13","unstructured":"Tooby, J. & Cosmides, L. The evolution of war and its cognitive foundations. 1\u201315 (Institute for Evolutionary Studies, Palo Alto, CA, 1988)."},{"key":"57259_CR14","doi-asserted-by":"publisher","first-page":"19","DOI":"10.1111\/j.1467-9280.2007.01842.x","volume":"18","author":"M Van Vugt","year":"2007","unstructured":"Van Vugt, M., Cremer, D. D. & Janssen, D. P. Gender differences in cooperation and competition: The male-warrior hypothesis. Psychol. Sci. 18, 19\u201323 (2007).","journal-title":"Psychol. Sci."},{"key":"57259_CR15","doi-asserted-by":"publisher","first-page":"933","DOI":"10.1037\/a0017931","volume":"98","author":"CD Navarrete","year":"2010","unstructured":"Navarrete, C. D., McDonald, M. M., Molina, L. E. & Sidanius, J. Prejudice at the nexus of race and gender: An outgroup male target hypothesis. J. Pers. Soc. Psychol. 98, 933\u2013945 (2010).","journal-title":"J. Pers. Soc. Psychol."},{"key":"57259_CR16","doi-asserted-by":"publisher","DOI":"10.1038\/srep29819","volume":"6","author":"A Tognetti","year":"2016","unstructured":"Tognetti, A., Dubois, D., Faurie, C. & Willinger, M. Men increase contributions to a public good when under sexual competition. Sci. Rep. 6, 29819, https:\/\/doi.org\/10.1038\/srep29819 (2016).","journal-title":"Sci. Rep."},{"key":"57259_CR17","doi-asserted-by":"publisher","first-page":"101","DOI":"10.1177\/1368430209342258","volume":"13","author":"M Van Vugt","year":"2010","unstructured":"Van Vugt, M. & Hardy, C. L. Cooperation for reputation: Wasteful contributions as costly signals in public goods. Group Process. Interg. 13, 101\u2013111 (2010).","journal-title":"Group Process. Interg."},{"key":"57259_CR18","doi-asserted-by":"publisher","first-page":"611","DOI":"10.1002\/ajhb.22281","volume":"24","author":"JA Mu\u00f1oz-Reyes","year":"2012","unstructured":"Mu\u00f1oz-Reyes, J. A., Gil-Burmann, C., Fink, B. & Turiegano, E. Physical strength, fighting ability, and aggressiveness in adolescents. Am. J. Hum. Biol. 24, 611\u2013617 (2012).","journal-title":"Am. J. Hum. Biol."},{"key":"57259_CR19","doi-asserted-by":"publisher","first-page":"718","DOI":"10.1177\/0956797611435133","volume":"23","author":"M Stirrat","year":"2012","unstructured":"Stirrat, M. & Perrett, D. I. Face structure predicts cooperation: Men with wider faces are more generous to their in-group when out-group competition is salient. Psychol. Sci. 23, 718\u2013722 (2012).","journal-title":"Psychol. Sci."},{"key":"57259_CR20","doi-asserted-by":"publisher","first-page":"258","DOI":"10.1002\/ab.20384","volume":"37","author":"AC Gallup","year":"2011","unstructured":"Gallup, A. C., O\u2019Brien, D. T. & Wilson, D. S. Intrasexual peer aggression and dating behavior during adolescence: an evolutionary perspective. Aggressive Behav. 37, 258\u2013267 (2011).","journal-title":"Aggressive Behav."},{"key":"57259_CR21","doi-asserted-by":"crossref","first-page":"296","DOI":"10.1177\/147470491201000209","volume":"21","author":"EH de Bruyn","year":"2012","unstructured":"de Bruyn, E. H., Cillessen, A. H. N. & Weisfeld, G. E. Dominance-popularity status, behavior, and the emergence of sexual activity in young adolescents. Evol. Psychol. 21, 296\u2013319 (2012).","journal-title":"Evol. Psychol."},{"key":"57259_CR22","doi-asserted-by":"publisher","first-page":"427","DOI":"10.1098\/rspb.1998.0312","volume":"265","author":"G Roberts","year":"1998","unstructured":"Roberts, G. Competitive altruism: from reciprocity to the handicap principle. Proc. R. Soc. Lond. B. Biol. Sci. 265, 427\u2013431 (1998).","journal-title":"Proc. R. Soc. Lond. B. Biol. Sci."},{"key":"57259_CR23","doi-asserted-by":"crossref","unstructured":"Cosmides, L. & Tooby, J. Cognitive adaptations for social exchange in The adapted mind: evolutionary psychology and the generation of culture (eds. Barkow, J. H., Cosmides, L. & Tooby, J.) 163\u2013228 (Oxford University Press, 1992).","DOI":"10.1093\/oso\/9780195060232.003.0004"},{"key":"57259_CR24","doi-asserted-by":"publisher","first-page":"103","DOI":"10.1037\/a0030398","volume":"104","author":"JT Cheng","year":"2013","unstructured":"Cheng, J. T., Tracy, J. L., Foulsham, T., Kingstone, A. & Henrich, J. Two ways to the top: Evidence that dominance and prestige are distinct yet viable avenues to social rank and influence. J. Pers. Soc. Psychol. 104, 103\u2013125 (2013).","journal-title":"J. Pers. Soc. Psychol."},{"key":"57259_CR25","doi-asserted-by":"publisher","first-page":"319","DOI":"10.1016\/j.neubiorev.2004.12.007","volume":"30","author":"J Archer","year":"2006","unstructured":"Archer, J. Testosterone and human aggression: an evaluation of the challenge hypothesis. Neurosci. Biobehav. Rev. 30, 319\u2013345 (2006).","journal-title":"Neurosci. Biobehav. Rev."},{"key":"57259_CR26","unstructured":"Breedlove, S. & Watson, N. Biological Psychology: An Introduction to Behavioral, Cognitive, and Clinical Neuroscience. 7th edn, 650 (Sinauer, 2013)."},{"key":"57259_CR27","doi-asserted-by":"publisher","first-page":"221","DOI":"10.1016\/j.neubiorev.2019.01.010","volume":"98","author":"Nicholas M. Grebe","year":"2019","unstructured":"Grebe, N. M., Sarafin, R. E., Strenth, C. R. & Zilioli, S. Pair-bonding, Fatherhood, and the Role of Testosterone: A Meta-Analytic Review. Neurosci. Biobehav. Rev.; https:\/\/doi.org\/10.1016\/j.neubiorev.2019.01.010 (2019).","journal-title":"Neuroscience & Biobehavioral Reviews"},{"key":"57259_CR28","doi-asserted-by":"publisher","first-page":"829","DOI":"10.1086\/285134","volume":"136","author":"JC Wingfield","year":"1990","unstructured":"Wingfield, J. C., Hegner, R. E., Dufty, A. M. Jr. & Ball, G. F. The \u201cchallenge hypothesis\u201d: Theoretical implications for patterns of testosterone secretion, mating systems, and breeding strategies. Am. Nat. 136, 829\u2013846 (1990).","journal-title":"Am. Nat."},{"key":"57259_CR29","doi-asserted-by":"publisher","unstructured":"Manning, J., Kilduff, L., Cook, C., Crewther, B. & Fink, B. Digit Ratio (2D:4D): A Biomarker for Prenatal Sex Steroids and Adult Sex Steroids in Challenge Situations. Front. Endocrinol., 5, https:\/\/doi.org\/10.3389\/fendo.2014.00009 (2014).","DOI":"10.3389\/fendo.2014.00009"},{"key":"57259_CR30","doi-asserted-by":"publisher","first-page":"2651","DOI":"10.1098\/rspb.2008.0873","volume":"275","author":"JM Carr\u00e9","year":"2008","unstructured":"Carr\u00e9, J. M. & McCormick, C. M. In your face: facial metrics predict aggressive behaviour in the laboratory and in varsity and professional hockey players. Proc. R. Soc. Lond. B. Biol. Sci. 275, 2651\u20132656 (2008).","journal-title":"Proc. R. Soc. Lond. B. Biol. Sci."},{"key":"57259_CR31","doi-asserted-by":"publisher","first-page":"163","DOI":"10.1016\/j.yfrne.2005.10.003","volume":"26","author":"CL Sisk","year":"2005","unstructured":"Sisk, C. L. & Zehr, J. L. Pubertal hormones organize the adolescent brain and behavior. Front. Neuroendocrinol. 26, 163\u2013174 (2005).","journal-title":"Front. Neuroendocrinol."},{"key":"57259_CR32","unstructured":"Manning, J. T. Digit ratio: A pointer to fertility, behavior, and health. (Rutgers University Press, 2002)."},{"key":"57259_CR33","doi-asserted-by":"crossref","unstructured":"Hodges-Simeon, C. R., Hanson Sobraske, K. N., Samore, T., Gurven, M. & Gaulin, S. J. C. Facial Width-To-Height Ratio (fWHR) Is Not Associated with Adolescent Testosterone Levels. PLoS One., 11, e0153083.","DOI":"10.1371\/journal.pone.0153083"},{"key":"57259_CR34","doi-asserted-by":"publisher","first-page":"e112157","DOI":"10.1371\/journal.pone.0112157","volume":"9","author":"S Sanchez-Pages","year":"2014","unstructured":"Sanchez-Pages, S., Rodriguez-Ruiz, C. & Turiegano, E. Facial Masculinity: How the Choice of Measurement Method Enables to Detect Its Influence on Behaviour. PLoS One 9, e112157, https:\/\/doi.org\/10.1371\/journal.pone.0112157 (2014).","journal-title":"PLoS One"},{"key":"57259_CR35","doi-asserted-by":"publisher","first-page":"534","DOI":"10.1177\/0363546503262202","volume":"32","author":"NA Evans","year":"2004","unstructured":"Evans, N. A. Current Concepts in Anabolic-Androgenic Steroids. Am. J. Sports Med. 32, 534\u2013542 (2004).","journal-title":"Am. J. Sports Med."},{"key":"57259_CR36","doi-asserted-by":"publisher","first-page":"215","DOI":"10.1016\/j.biopsycho.2004.05.001","volume":"68","author":"AA Bailey","year":"2005","unstructured":"Bailey, A. A. & Hurd, P. L. Finger length ratio (2D:4D) correlates with physical aggression in men but not in women. Biol. Psychol. 68, 215\u2013222 (2005).","journal-title":"Biol. Psychol."},{"key":"57259_CR37","doi-asserted-by":"publisher","first-page":"51","DOI":"10.1016\/j.avb.2017.01.008","volume":"33","author":"JJ Turanovic","year":"2017","unstructured":"Turanovic, J. J., Pratt, T. C. & Piquero, A. R. Exposure to fetal testosterone, aggression, and violent behavior: A meta-analysis of the 2D:4D digit ratio. Aggr. Violent Behav. 33, 51\u201361 (2017).","journal-title":"Aggr. Violent Behav."},{"key":"57259_CR38","doi-asserted-by":"publisher","first-page":"755","DOI":"10.1016\/j.paid.2006.08.009","volume":"42","author":"MH McIntyre","year":"2007","unstructured":"McIntyre, M. H. et al. Finger length ratio (2D: 4D) and sex differences in aggression during a simulated war game. Pers. Individ. Dif. 42, 755\u2013764 (2007).","journal-title":"Pers. Individ. Dif."},{"key":"57259_CR39","unstructured":"Isbell, J. Status relevant social context, group membership, and finger length ratio (2D:4D) as predictors of online socioeconomic behavior Doctor of Philosophy thesis, University of Oregon, (2017)."},{"key":"57259_CR40","doi-asserted-by":"publisher","first-page":"e0132726","DOI":"10.1371\/journal.pone.0132726","volume":"10","author":"SN Geniole","year":"2015","unstructured":"Geniole, S. N., Denson, T. F., Dixson, B. J., Carr\u00e9, J. M. & McCormick, C. M. Evidence from Meta-Analyses of the Facial Width-to-Height Ratio as an Evolved Cue of Threat. PLoS One 10, e0132726, https:\/\/doi.org\/10.1371\/journal.pone.0132726 (2015).","journal-title":"PLoS One"},{"key":"57259_CR41","doi-asserted-by":"publisher","first-page":"e0122637","DOI":"10.1371\/journal.pone.0122637","volume":"10","author":"MP Haselhuhn","year":"2015","unstructured":"Haselhuhn, M. P., Ormiston, M. E. & Wong, E. M. Men\u2019s Facial Width-to-Height Ratio Predicts Aggression: A Meta-Analysis. PLoS One 10, e0122637, https:\/\/doi.org\/10.1371\/journal.pone.0122637 (2015).","journal-title":"PLoS One"},{"key":"57259_CR42","doi-asserted-by":"publisher","first-page":"e30399","DOI":"10.1371\/journal.pone.0030399","volume":"7","author":"BR Spisak","year":"2012","unstructured":"Spisak, B. R., Dekker, P. H., Kr\u00fcger, M. & Van Vugt, M. Warriors and peacekeepers: Testing a biosocial implicit leadership hypothesis of intergroup relations using masculine and feminine faces. PLoS One 7, e30399, https:\/\/doi.org\/10.1371\/journal.pone.0030399 (2012).","journal-title":"PLoS One"},{"key":"57259_CR43","doi-asserted-by":"publisher","first-page":"334","DOI":"10.1016\/j.evolhumbehav.2016.11.002","volume":"38","author":"A Sell","year":"2017","unstructured":"Sell, A. et al. Physically strong men are more militant: A test across four countries. Evol. Hum. Behav. 38, 334\u2013340 (2017).","journal-title":"Evol. Hum. Behav."},{"key":"57259_CR44","doi-asserted-by":"publisher","first-page":"151","DOI":"10.1348\/000712608X324359","volume":"100","author":"K Millet","year":"2009","unstructured":"Millet, K. & Dewitte, S. The presence of aggression cues inverts the relation between digit ratio (2D: 4D) and prosocial behaviour in a dictator game. Br. J. Psychol. 100, 151\u2013162 (2009).","journal-title":"Br. J. Psychol."},{"key":"57259_CR45","doi-asserted-by":"publisher","first-page":"e60419","DOI":"10.1371\/journal.pone.0060419","volume":"8","author":"P Bra\u00f1as-Garza","year":"2013","unstructured":"Bra\u00f1as-Garza, P., Kov\u00e1\u0159\u00edk, J. & Neyse, L. Second-to-fourth digit ratio has a non-monotonic impact on altruism. PLoS One 8, e60419, https:\/\/doi.org\/10.1371\/journal.pone.0060419 (2013).","journal-title":"PLoS One"},{"key":"57259_CR46","doi-asserted-by":"publisher","first-page":"355","DOI":"10.1016\/j.physbeh.2009.11.013","volume":"99","author":"S Sanchez-Pages","year":"2010","unstructured":"Sanchez-Pages, S. & Turiegano, E. Testosterone, facial symmetry and cooperation in the prisoners\u2019 dilemma. Physiol. Behav. 99, 355\u2013361 (2010).","journal-title":"Physiol. Behav."},{"key":"57259_CR47","doi-asserted-by":"publisher","first-page":"111","DOI":"10.1016\/j.biopsycho.2005.06.001","volume":"71","author":"K Millet","year":"2006","unstructured":"Millet, K. & Dewitte, S. Second to fourth digit ratio and cooperative behavior. Biol. Psychol. 71, 111\u2013115 (2006).","journal-title":"Biol. Psychol."},{"key":"57259_CR48","doi-asserted-by":"publisher","first-page":"427","DOI":"10.1016\/j.evolhumbehav.2013.08.002","volume":"34","author":"A Tognetti","year":"2013","unstructured":"Tognetti, A., Berticat, C., Raymond, M. & Faurie, C. Is cooperativeness readable in static facial features? An inter-cultural approach. Evol. Hum. Behav. 34, 427\u2013432 (2013).","journal-title":"Evol. Hum. Behav."},{"key":"57259_CR49","doi-asserted-by":"publisher","unstructured":"Kaltwasser, L., Mikac, U., Bu\u0161ko, V. & Hildebrandt, A. No Robust Association between Static Markers of Testosterone and Facets of Socio-Economic Decision Making. Front. Behav. Neurosci., 11, https:\/\/doi.org\/10.3389\/fnbeh.2017.00250 (2017).","DOI":"10.3389\/fnbeh.2017.00250"},{"key":"57259_CR50","doi-asserted-by":"publisher","first-page":"636","DOI":"10.1016\/j.paid.2010.12.009","volume":"50","author":"ME Price","year":"2011","unstructured":"Price, M. E., Kang, J., Dunn, J. & Hopkins, S. Muscularity and attractiveness as predictors of human egalitarianism. Pers. Individ. Dif. 50, 636\u2013640 (2011).","journal-title":"Pers. Individ. Dif."},{"key":"57259_CR51","doi-asserted-by":"publisher","first-page":"170","DOI":"10.1016\/j.evolhumbehav.2017.12.006","volume":"39","author":"PK Durkee","year":"2018","unstructured":"Durkee, P. K., Goetz, A. T. & Lukaszewski, A. W. Formidability assessment mechanisms: Examining their speed and automaticity. Evol. Hum. Behav. 39, 170\u2013178 (2018).","journal-title":"Evol. Hum. Behav."},{"key":"57259_CR52","doi-asserted-by":"publisher","first-page":"46","DOI":"10.1016\/j.cognition.2012.12.002","volume":"127","author":"C Holbrook","year":"2013","unstructured":"Holbrook, C. & Fessler, D. M. Sizing up the threat: The envisioned physical formidability of terrorists tracks their leaders\u2019 failures and successes. Cognition 127, 46\u201356 (2013).","journal-title":"Cognition"},{"key":"57259_CR53","doi-asserted-by":"publisher","first-page":"15073","DOI":"10.1073\/pnas.0904312106","volume":"106","author":"A Sell","year":"2009","unstructured":"Sell, A., Tooby, J. & Cosmides, L. Formidability and the logic of human anger. Proc. Natl. Acad. Sci. USA 106, 15073\u201315078 (2009).","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"57259_CR54","doi-asserted-by":"publisher","first-page":"921","DOI":"10.1098\/rsbl.2012.0591","volume":"8","author":"G Stulp","year":"2012","unstructured":"Stulp, G., Kordsmeyer, T., Buunk, A. P. & Verhulst, S. Increased aggression during human group contests when competitive ability is more similar. Biol. Lett. 8, 921\u2013923 (2012).","journal-title":"Biol. Lett."},{"key":"57259_CR55","doi-asserted-by":"publisher","unstructured":"Mu\u00f1oz-Reyes, J. A. et al. Muscularity and Strength Affect Individual Variation in Self-Perception of Fighting Ability in Men. Front. Psychol., 10, https:\/\/doi.org\/10.3389\/fpsyg.2019.00018 (2019).","DOI":"10.3389\/fpsyg.2019.00018"},{"key":"57259_CR56","doi-asserted-by":"crossref","unstructured":"Puts, D. A., Bailey, D. H. & Reno, P. L. Contest competition in men in The handbook of evolutionary psychology (ed. Buss, D. M.) 835\u2013402. (Hoboken: Wiley, 2015)","DOI":"10.1002\/9781119125563.evpsych113"},{"key":"57259_CR57","doi-asserted-by":"publisher","first-page":"339","DOI":"10.1007\/BF00435849","volume":"75","author":"DR Cherek","year":"1981","unstructured":"Cherek, D. R. Effects of smoking different doses of nicotine on human aggressive behavior. Psychopharmacology 75, 339\u2013345 (1981).","journal-title":"Psychopharmacology"},{"key":"57259_CR58","doi-asserted-by":"publisher","first-page":"59","DOI":"10.1016\/0162-3095(85)90041-X","volume":"6","author":"M Wilson","year":"1985","unstructured":"Wilson, M. & Daly, M. Competitiveness, risk taking, and violence: The young male syndrome. Ethol. Sociobiol. 6, 59\u201373 (1985).","journal-title":"Ethol. Sociobiol."},{"key":"57259_CR59","doi-asserted-by":"publisher","first-page":"118","DOI":"10.1016\/j.evolhumbehav.2013.11.005","volume":"35","author":"JA Mu\u00f1oz-Reyes","year":"2014","unstructured":"Mu\u00f1oz-Reyes, J. A., Pita, M., Arjona, M., Sanchez-Pages, S. & Turiegano, E. Who is the fairest of them all? The independent effect of attractive features and self-perceived attractiveness on cooperation among women. Evol. Hum. Behav. 35, 118\u2013125 (2014).","journal-title":"Evol. Hum. Behav."},{"key":"57259_CR60","doi-asserted-by":"publisher","first-page":"619","DOI":"10.1002\/ajhb.21054","volume":"22","author":"J H\u00f6nekopp","year":"2010","unstructured":"H\u00f6nekopp, J. & Watson, S. Meta\u2010analysis of digit ratio 2D: 4D shows greater sex difference in the right hand. Am. J. Hum. Biol. 22, 619\u2013630 (2010).","journal-title":"Am. J. Hum. Biol."},{"key":"57259_CR61","doi-asserted-by":"publisher","first-page":"319","DOI":"10.1080\/02109395.2014.922259","volume":"35","author":"J-A Mu\u00f1oz-Reyes","year":"2014","unstructured":"Mu\u00f1oz-Reyes, J.-A., Gil-Burmann, C. & Turiegano, E. Digit Ratio 2D:4D, facial masculinization and aggressiveness in Spanish adolescents \/ \u00cdndice 2D:4D, masculinizaci\u00f3n facial y agresividad en adolescentes espa\u00f1oles. Estud. Psicol. 35, 319\u2013340 (2014).","journal-title":"Estud. Psicol."},{"key":"57259_CR62","doi-asserted-by":"publisher","first-page":"e23235","DOI":"10.1002\/ajhb.23235","volume":"31","author":"P Polo","year":"2019","unstructured":"Polo, P., Mu\u00f1oz\u2010Reyes, J. A., Pita, M., Shackelford, T. K. & Fink, B. Testosterone\u2010dependent facial and body traits predict men\u2019s sociosexual attitudes and behaviors. Am. J. Hum. Biol. 31, e23235 (2019).","journal-title":"Am. J. Hum. Biol."},{"key":"57259_CR63","doi-asserted-by":"publisher","first-page":"1061","DOI":"10.1038\/ejcn.2017.27","volume":"71","author":"A Bosy-Westphal","year":"2017","unstructured":"Bosy-Westphal, A. et al. Quantification of whole-body and segmental skeletal muscle mass using phase-sensitive 8-electrode medical bioelectrical impedance devices. Eur. J. Clin. Nutr. 71, 1061\u20131067 (2017).","journal-title":"Eur. J. Clin. Nutr."},{"key":"57259_CR64","doi-asserted-by":"publisher","first-page":"610","DOI":"10.1016\/j.clnu.2011.04.001","volume":"30","author":"CHY Ling","year":"2011","unstructured":"Ling, C. H. Y. et al. Accuracy of direct segmental multi-frequency bioimpedance analysis in the assessment of total body and segmental body composition in middle-aged adult population. Clin. Nutr. 30, 610\u2013615 (2011).","journal-title":"Clin. Nutr."},{"key":"57259_CR65","doi-asserted-by":"publisher","first-page":"103","DOI":"10.1016\/j.yhbeh.2016.04.006","volume":"92","author":"SN Geniole","year":"2017","unstructured":"Geniole, S. N., MacDonell, E. T. & McCormick, C. M. The Point Subtraction Aggression Paradigm as a laboratory tool for investigating the neuroendocrinology of aggression and competition. Horm. Behav. 92, 103\u2013116 (2017).","journal-title":"Horm. Behav."},{"key":"57259_CR66","unstructured":"Baron, R. & Richardson, D. Human aggression. (Plenum Press, 1994)."},{"key":"57259_CR67","doi-asserted-by":"publisher","first-page":"299","DOI":"10.1023\/A:1026277420119","volume":"6","author":"J Zelmer","year":"2003","unstructured":"Zelmer, J. Linear public goods experiments: A meta-analysis. Exper. Econ. 6, 299\u2013310 (2003).","journal-title":"Exper. Econ."},{"key":"57259_CR68","doi-asserted-by":"publisher","first-page":"171","DOI":"10.1007\/s10683-006-9159-4","volume":"10","author":"U Fischbacher","year":"2007","unstructured":"Fischbacher, U. z-Tree: Zurich toolbox for ready-made economic experiments. Exper. Econ. 10, 171\u2013178 (2007).","journal-title":"Exper. Econ."},{"key":"57259_CR69","unstructured":"Burnham, K. P. & Anderson, D. Model selection and multi-model inference. A Pratical information-theoric approch. 2nd edn, 488 (Springer, 2002)."},{"key":"57259_CR70","doi-asserted-by":"crossref","unstructured":"West, B. T., Welch, K. B. & Galecki, A. T. Linear mixed models: a practical guide using statistical software. (Chapman & Hall, 2007).","DOI":"10.1201\/9781420010435"},{"key":"57259_CR71","doi-asserted-by":"publisher","first-page":"271","DOI":"10.1016\/j.jesp.2008.08.018","volume":"45","author":"M Yuki","year":"2009","unstructured":"Yuki, M. & Yokota, K. The primal warrior: Outgroup threat priming enhances intergroup discrimination in men but not women. J. Exp. Soc. Psychol. 45, 271\u2013274 (2009).","journal-title":"J. Exp. Soc. Psychol."},{"key":"57259_CR72","doi-asserted-by":"publisher","first-page":"1293","DOI":"10.1126\/science.1168112","volume":"324","author":"S Bowles","year":"2009","unstructured":"Bowles, S. Did Warfare Among Ancestral Hunter-Gatherers Affect the Evolution of Human Social Behaviors? Science 324, 1293\u20131298 (2009).","journal-title":"Science"},{"key":"57259_CR73","doi-asserted-by":"publisher","first-page":"636","DOI":"10.1126\/science.1144237","volume":"318","author":"J-K Choi","year":"2007","unstructured":"Choi, J.-K. & Bowles, S. The coevolution of parochial altruism and war. Science 318, 636\u2013640 (2007).","journal-title":"Science"},{"key":"57259_CR74","doi-asserted-by":"publisher","first-page":"0141539","DOI":"10.1098\/rspb.2014.1539","volume":"281","author":"H Rusch","year":"2014","unstructured":"Rusch, H. The evolutionary interplay of intergroup conflict and altruism in humans: a review of parochial altruism theory and prospects for its extension. Proc. R. Soc. Lond. B. Biol. Sci. 281, 0141539, https:\/\/doi.org\/10.1098\/rspb.2014.1539 (2014).","journal-title":"Proc. R. Soc. Lond. B. Biol. Sci."},{"key":"57259_CR75","doi-asserted-by":"publisher","first-page":"2329","DOI":"10.1177\/0956797613493294","volume":"24","author":"SMM Goetz","year":"2013","unstructured":"Goetz, S. M. M. et al. Social Status Moderates the Relationship Between Facial Structure and Aggression. Psychol. Sci. 24, 2329\u20132334 (2013).","journal-title":"Psychol. Sci."},{"key":"57259_CR76","doi-asserted-by":"publisher","first-page":"512","DOI":"10.1002\/ab.21771","volume":"44","author":"ET MacDonell","year":"2018","unstructured":"MacDonell, E. T., Geniole, S. N. & McCormick, C. M. Force versus fury: Sex differences in the relationships among physical and psychological threat potential, the facial width-to-height ratio, and judgements of aggressiveness. Aggressive Behav. 44, 512\u2013523 (2018).","journal-title":"Aggressive Behav."},{"key":"57259_CR77","doi-asserted-by":"publisher","first-page":"627","DOI":"10.1016\/j.paid.2007.01.005","volume":"43","author":"J Archer","year":"2007","unstructured":"Archer, J. & Thanzami, V. The relation between physical aggression, size and strength, among a sample of young Indian men. Pers. Individ. Dif. 43, 627\u2013633 (2007).","journal-title":"Pers. Individ. Dif."},{"key":"57259_CR78","doi-asserted-by":"publisher","first-page":"575","DOI":"10.1098\/rspb.2008.1177","volume":"276","author":"A Sell","year":"2009","unstructured":"Sell, A. et al. Human adaptations for the visual assessment of strength and fighting ability from the body and face. Proc. R. Soc. Lond. B. Biol. Sci. 276, 575\u2013584 (2009).","journal-title":"Proc. R. Soc. Lond. B. Biol. Sci."},{"key":"57259_CR79","unstructured":"Bra\u00f1as-Garza, P., Esp\u00edn, A. M., Garcia, T. & Kov\u00e1\u0159\u00edk, J. Digit ratio (2D: 4D) predicts pro-social behavior in economic games only for unsatisfied individuals. MPRA Paper No. 89142 (2018)."},{"key":"57259_CR80","doi-asserted-by":"publisher","unstructured":"Galizzi, M. M. & Nieboer, J. Digit ratio (2D: 4D) and altruism: evidence from a large, multi-ethnic sample. Front. Behav. Neurosci., 9, https:\/\/doi.org\/10.3389\/fnbeh.2015.00041 (2015).","DOI":"10.3389\/fnbeh.2015.00041"},{"key":"57259_CR81","doi-asserted-by":"publisher","first-page":"E4","DOI":"10.1038\/nature11136","volume":"485","author":"J van Honk","year":"2012","unstructured":"van Honk, J., Montoya, E. R., Bos, P. A., Van Vugt, M. & Terburg, D. New evidence on testosterone and cooperation. Nature 485, E4\u2013E5 (2012).","journal-title":"Nature"}],"container-title":["Scientific Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.nature.com\/articles\/s41598-019-57259-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-019-57259-0","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-019-57259-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,7,30]],"date-time":"2024-07-30T04:24:12Z","timestamp":1722313452000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.nature.com\/articles\/s41598-019-57259-0"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,1,15]]},"references-count":81,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2020,12]]}},"alternative-id":["57259"],"URL":"https:\/\/doi.org\/10.1038\/s41598-019-57259-0","relation":{},"ISSN":["2045-2322"],"issn-type":[{"value":"2045-2322","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,1,15]]},"assertion":[{"value":"15 August 2019","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"20 December 2019","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"15 January 2020","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"The authors declare no competing interests.","order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}}],"article-number":"375"}}