title: Testosterone and androgen receptor gene polymorphism are associated with confidence and competitiveness in men.
abstract: A contribution to a special issue on Hormones and Human Competition. Studies in non-human animals and humans have demonstrated the important role of testosterone in competitive interactions. Here, we investigated whether endogenous testosterone levels predict the decision to compete, in a design excluding spite as a motive underlying competitiveness. In a laboratory experiment with real monetary incentives, 181 men solved arithmetic problems, first under a noncompetitive piece rate, followed by a competition incentive scheme. We also assessed several parameters relevant to competition, such as risk taking, performance, and confidence in one's own performance. Salivary testosterone levels were measured before and 20min after the competition task using mass spectrometry. Participants were also genotyped for the CAG repeat polymorphism of the androgen receptor gene, known to influence the efficacy of testosterone signaling in a reciprocal relationship to the number of CAG repeats. We observed a significant positive association between basal testosterone levels and the decision to compete, and that higher testosterone levels were related to greater confidence in one's own performance. Whereas the number of CAG repeats was not associated with the choice to compete, a lower number of CAG repeats was related to greater confidence in those who chose to compete, but this effect was attributable to the polymorphism's effect on actual performance. An increase in testosterone levels was observed following the experiment, and this increase varied with self-reported high-school math grades. We expand upon the latest research by documenting effects of the androgen system in confidence in one's own ability, and conclude that testosterone promotes competitiveness without spite.
authors.affiliation: Neuropsychopharmacology and Biopsychology Unit, Faculty of Psychology, University of Vienna, Austria. Electronic address: christoph.eisenegger@univie.ac.at.
authors.forename: Christoph
authors.initials: C
authors.lastname: Eisenegger
authors.affiliation: Department of Genetic Psychology, Faculty of Psychology, Ruhr-University Bochum, Germany. Electronic address: robert.kumsta@rub.de.
authors.forename: Robert
authors.initials: R
authors.lastname: Kumsta
authors.affiliation: Department of Economics, Royal Holloway, University of London, United Kingdom.
authors.forename: Michael
authors.initials: M
authors.lastname: Naef
authors.affiliation: Department of Reproductive Medicine, University of Münster, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Gromoll
authors.affiliation: Department of Psychology, Laboratory for Biological and Personality Psychology, University of Freiburg, Freiburg, Germany; Freiburg Brain Imaging Center, University Medical Center, University of Freiburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Heinrichs
mesh_terms: D000328:Adult; D003163:Competitive Behavior / Q000502:physiology*; D056726:Genetic Association Studies; D005838:Genotype; D006801:Humans; D008297:Male; D010551:Personality / Q000235:genetics*; D011110:Polymorphism, Genetic; D011340:Problem Solving / Q000502:physiology; D011944:Receptors, Androgen / Q000235:genetics*; D013739:Testosterone / Q000032:analysis*; D018911:Trinucleotide Repeats; D055815:Young Adult
chemical_list: D011944:Receptors, Androgen; D013739:Testosterone