Testosterone Rex

by Cordelia Fine

  61. For example, Apicella & Dreber (2015), ibid.; Dreber et al. (2014), ibid.; Flory, J. A., Leibbrandt, A., & List, J. A. (2015). Do competitive work places deter female workers? A large-scale natural field experiment on gender differences on job-entry decisions: Review of Economic Studies, 82(1) 122–155; Grosse, N. D., Riener, G., & Dertwinkel-Kalt, M. (2014). Explaining gender differences in competitiveness: Testing a theory on gender-task stereotypes: working paper, University of Mannheim; Günther, C., Ekinci, N. A., Schwieren, C., & Strobel, M. (2010). Women can’t jump?—An experiment on competitive attitudes and stereotype threat. Journal of Economic Behavior and Organization, 75(3), 395–401; Wieland, A., & Sarin, R. (2012). Domain specificity of sex differences in competition. Journal of Economic Behavior and Organization, 83(1), 151–157.

  62. See discussion in Khachatryan, K., Dreber, A., von Essen, E., & Ranehill, E. (2015). Gender and preferences at a young age: Evidence from Armenia. Journal of Economic Behavior and Organization, 118, 318–332. See also Sutter, M., & Glätzle-Rützler, D. (2014). Gender differences in the willingness to compete emerge early in life and persist. Management Science, 61(10), 2339–2354.

  63. Cameron, L., Erkal, N., Gangadharan, L., & Meng, X. (2013). Little emperors: Behavioral impacts of China’s one-child policy. Science, 339(6122), 953–957; Cárdenas, J.-C., Dreber, A., von Essen, E., & Ranehill, E. (2012). Gender differences in competitiveness and risk taking: Comparing children in Colombia and Sweden. Journal of Economic Behavior and Organization, 83(1), 11–23; Khachatryan et al. (2015), ibid.; Zhang, Y. (2015). Culture, institutions, and the gender gap in competitive inclination: Evidence from the Communist experiment in China. Available at SSRN: http://ssrn.com/abstract=2268874 or http://dx.doi.org/10.2139/ssrn.2268874.

  64. Gneezy, U., Leonard, K. L., & List, J. A. (2009). Gender differences in competition: Evidence from a matrilineal and a patriarchal society. Econometrica, 77(5), 1637–1664.

  65. Andersen, S., Ertac, S., Gneezy, U., List, J. A., & Maximiano, S. (2013). Gender, competitiveness, and socialization at a young age: Evidence from a matrilineal and a patriarchal society. Review of Economics and Statistics, 95(4), 1438–1443.

  66. Sutter & Glätzle-Rützler (2014), ibid.

  67. Kay, J. (December 10, 2013). Is it better to play it safe or to place bets that risk bankruptcy? Financial Times. Retrieved from http://www.ft.com/intl/cms/s/0/292e514e-60ff-11e3-b7f1-00144feabdc0.html#axzz3wbxCXczm on January 8, 2016. Kay does note that “Like all attempts to account for our behaviour by delving into our evolutionary past, this story should be taken with a large pinch of salt. But there does not have to be any historic truth in my narrative for its fundamental premise to be true. People who take foolish risks which mostly come off are likely to appear attractive mates and leaders.” Given the prior evolutionary story, it seems to propose that by “people” here, he means “men.”

  68. Butt, C. (September 10, 2015). Female surgeons feel obliged to give sexual favours, report finds. Sydney Morning Herald. Retrieved from http://www.smh.com.au/national/bullying-endemic-among-surgeons-but-victims-too-scared-to-speak-up-report-finds-20150909-gjiuxl.html on September 10, 2015.

  69. Silvester, M., & Perkins, M. (December 9, 2015). Shame files: Policewomen targeted for sex from the day they join the force. The Age. Retrieved from http://www.theage.com.au/victoria/a-new-report-says-policewomen-are-targeted-for-sex-from-the-day-they-join-20151208-glidtv.html on December 30, 2015.

  CHAPTER 6: THE HORMONAL ESSENCE OF THE T-REX?

  1. Adkins-Regan, E. (2005). Hormones and animal social behavior. Princeton, NJ: Princeton University Press. Quoted on p. 21.

  2. Browne, K. R. (2012). Mind which gap? The selective concern over statistical sex disparities. Florida International University Law Review, 8, 271–286. Quoted on pp. 284–285, references removed.

  3. For example, Hoffman, M., & Yoeli, E. (Winter, 2013). The risks of avoiding a debate on gender differences. Rady Business Journal; Cronqvist, H., Previtero, A., Siegel, S., & White, R. E. (2016). The fetal origins hypothesis in finance: Prenatal environment, the gender gap, and investor behavior. Review of Financial Studies, 29(3), 739–786.

  4. Herbert, J. (2015). Testosterone: Sex, power, and the will to win. Oxford, UK: Oxford University Press. Quoted on p. 22.

  5. Herbert, J. (May 14, 2015). Sex, cars, and the power of testosterone. OUP Blog. Retrieved from http://blog.oup.com/2015/05/sex-cars-testosterone/ on July 16, 2015.

  6. Francis, R. C. (2004). Why men won’t ask for directions: The seductions of sociobiology. Princeton, NJ: Princeton University Press. Quoted on p. 147. First reference to “Teststerone Rex” on p. 143.

  7. For humans, the primary account is the biosocial model of Mazur (1985) and Mazur and Booth (1998). This proposes reciprocal influences between T and status seeking, in both women and men. Thus, higher levels of T promote status-seeking behaviour, and success feeds back to increase T levels (while failure decreases it). Mazur, A. (1985). A biosocial model of status in face-to-face primate groups. Social Forces, 64(2), 377–402; Mazur, A., & Booth, A. (1998). Testosterone and dominance in men. Behavioral and Brain Sciences, 21, 353–397. The other major theoretical framework is the challenge hypothesis, in which T changes are assumed to facilitate trade-offs between competition (or “challenge”) and parenting. Wingfield, J. C., Hegner, R. E., Dufty, A. M., Jr., & Ball, G. F. (1990). The “challenge hypothesis”: Theoretical implications for patterns of testosterone secretion, mating systems, and breeding strategies. American Naturalist, 136(6), 829–846.

  8. van Anders, S. M. (2013). Beyond masculinity: Testosterone, gender/sex, and human social behavior in a comparative context. Frontiers in Neuroendocrinology, 34(3), 198–210. One primary and important purpose of this paper is to show how the common conflation of high T with “masculinity” and low T with “femininity,” rather than more specifically with competition and nurturance, has led to inaccurate predictions that, for instance, high T will be associated with sexuality and low T with parenting. But, as van Anders points out, sexual behaviour can be either competitive or nurturant, or even both, and there are both nurturant and competitive elements to parenting. Van Anders shows how moving beyond the “pretheory” assumption that “T = masculinity” can help make sense of apparently contradictory findings, and guide better research.

  9. What follows borrows extensively from Francis (2004), ibid.

  10. Francis, R. C., Jacobson, B., Wingfield, J. C., & Fernald, R. D. (1992). Castration lowers aggression but not social dominance in male Haplochromis burtoni (Cichlidae). Ethology, 90(3), 247–255.

  11. Francis, R. C., Soma, K., & Fernald, R. D. (1993). Social regulation of the brain-pituitary-gonadal axis. Proceedings of the National Academy of Sciences, 90(16), 7794–7798.

  12. Francis et al. (1992), ibid. Quoted on p. 253.

  13. Also see discussion in van Anders, S., & Watson, N. (2006). Social neuroendocrinology: Effects of social contexts and behaviors on sex steroids in humans. Human Nature, 17(2), 212–237.

  14. Hrdy, S. B. (1986). Empathy, polyandry, and the myth of the coy female. In R. Bleier (Ed.), Feminist approaches to science (pp. 119–146). New York: Pergamon Press. Quoted on p. 141, referring to the work of Van den Berghe, E. (1984). Female competition, parental care, and reproductive success in salmon. Paper presented at Animal Behavior Society Meetings, Cheney, Washington, August 13–17.

  15. Adkins-Regan (2005), ibid. Quoted on p. 51.

  16. Joel, D. (2012). Genetic-gonadal-genitals sex (3G-sex) and the misconception of brain and gender, or, why 3G-males and 3G-females have intersex brain and intersex gender. Biology of Sex Differences, 3(27). Quoted on p. 4.

  17. Sapolsky, R. (1997). Junk food monkeys: And other essays on the biology of the human predicament. London: Headline. Quoted on p. 127, footnote removed at the end of the second quotation.

  18. See Freeman, E. R., Bloom, D. A., & McGuire, E. J. (2001). A brief history of testosterone. Journal of Urology, 165(2), 371–373. See also Adkins-Regan
(2005), ibid.

  19. Adkins-Regan (2005), ibid. Quoted on p. 3.

  20. Moore, C. (1992). The role of maternal stimulation in the development of sexual behavior and its neural basis. Annals of the New York Academy of Sciences, 662(1), 160–177.

  21. Oliveira (2004) describes this as the effect of testosterone on “somatic releasers”—that is, bodily effects that then influence the behaviour of conspecifics. Oliveira, R. F. (2004). Social modulation of androgens in vertebrates: Mechanisms and function. Advances in the Study of Behavior, 34, 165–239. For examples, see Table 1 on p. 172. Oliveira also provides examples of effects of testosterone on the sensory system and “effectors” (for example, effects on the muscles involved in producing mate calls in birds).

  22. Account drawn from a far more detailed description provided by Adkins-Regan (2005), ibid.

  23. See Adkins-Regan (2005), ibid., pp. 13–16, referring to both genomic (slower) and non-genomic (faster) effects. This is also well summarized in Oliveira, R. F. (2009). Social behavior in context: Hormonal modulation of behavioral plasticity and social competence. Integrative and Comparative Biology, 49(4), 423–440. See also Cardoso et al. (2015), who categorize three different types of social plasticity: fixed alternative phenotypes (not applicable in the case of humans, but in other species); developmental plasticity (such as the transition between pre- and post-pubescence), and behavioural flexibility. To focus on the two categories relevant to humans, developmental plasticity is proposed to involve (re)organization of structures (including the brain) and epigenetic effects, while behavioural flexibility is activational and involves biochemical switching at the neural level, and transient changes in gene expression at the genomic level. Cardoso, S. D., Teles, M. C., & Oliveira, R. F. (2015). Neurogenomic mechanisms of social plasticity. Journal of Experimental Biology, 218(1), 140–149. See Table 1, p. 142.

  24. Described in Pfaff, D. W. (2010). Man and woman: An inside story. Oxford, UK: Oxford University Press. See also Dufy, B., & Vincent, J. D. (1980). Effects of sex steroids on cell membrane excitability: A new concept for the action of steroids on the brain. In D. de Wied & P. van Keep (Eds.), Hormones and the brain (pp. 29–41). Lancaster, UK: MTP Press.

  25. Adkins-Regan (2005), ibid. Quoted on p. 15.

  26. See Chapter 1, Adkins-Regan (2005), ibid.

  27. Adkins-Regan (2005), ibid. Quoted on p. 16.

  28. Francis (2004), ibid., makes the point that “Of all the factors relevant to sexual development, steroid hormones, such as testosterone, are perhaps the easiest to measure, manipulate, and monitor, so they tend to be accorded more explanatory weight than other developmental factors.” Quoted on pp. 143–144.

  29. Gleason, E. D., Fuxjager, M. J., Oyegbile, T. O., & Marler, C. A. (2009). Testosterone release and social context: When it occurs and why. Frontiers in Neuroendocrinology, 30(4), 460–469. Quoted on p. 460.

  30. See, for example, Adkins-Regan (2005), ibid., pp. 218–222. See also Adkins-Regan, E. (2012). Hormonal organization and activation: Evolutionary implications and questions. General and Comparative Endocrinology, 176(3), 279–285.

  31. It’s surprisingly hard to find male/female norms for testosterone levels. As a methods paper on T measurement by van Anders et al. (2014) makes clear, any such “norms” would have to take into account the considerable variability introduced by factors such as season, time of day, relationship status, body weight, and so on. van Anders, S. M., Goldey, K. L., & Bell, S. N. (2014). Measurement of testosterone in human sexuality research: Methodological considerations. Archives of Sexual Behavior, 43(2), 231–250. But with all due caveats in place, an effect size of about d = 3 is estimated from samples from work by van Anders and colleagues, who commonly include both sexes in their research. For reference ranges for testosterone for children and adults, using a more sensitive measurement technique, see Kushnir, M. M., Blamires, T., Rockwood, A. L., Roberts, W. L., Yue, B., Erdogan, E., et al. (2010). Liquid chromatography: Tandem mass spectrometry assay for androstenedione, dehydroepiandrosterone, and testosterone with pediatric and adult reference intervals. Clinical Chemistry, 56(7), 1138–1147.

  32. For example, de Vries, G. (2004). Sex differences in adult and developing brains: Compensation, compensation, compensation. Endocrinology, 145(3), 1063–1068.

  33. For example, Bancroft, J. (2002). Sexual effects of androgens in women: Some theoretical considerations. Fertility and Sterility, 77(Suppl. 4), 55–59; Bancroft, J. (2005). The endocrinology of sexual arousal. Journal of Endocrinology, 186(3), 411–427.

  34. Sherwin, B. (1988). A comparative analysis of the role of androgen in human male and female sexual behavior: Behavioral specificity, critical thresholds, and sensitivity. Psychobiology, 16(4), 416–425. For evidence of sex differences in oestrogen receptors, see Gillies, G. E., & McArthur, S. (2010). Estrogen actions in the brain and the basis for differential action in men and women: A case for sex-specific medicines. Pharmacological Reviews, 62(2), 155–198.

  35. Bancroft (2002, 2005), ibid.

  36. A point made by van Anders (2013), ibid.; Adkins-Regan (2005), ibid. The absence of T research in women is also observed by Fausto-Sterling, A. (1992). Myths of gender: Biological theories about women and men. New York: Basic Books. It should be said, however, that the relative dearth of evidence with women was not simply due to a lack of interest in testosterone’s effects on women, but was also related to technical difficulties accurately measuring their lower levels, misplaced concerns that the menstrual cycle might lead to significant variation in T (it doesn’t), and the lowering of T by the use of oral contraceptives. However, these lower levels don’t affect change in T in response to competition. For discussion of these and other issues, see van Anders et al. (2014), ibid.

  37. van Anders (2013), ibid. Quoted on p. 198.

  38. Healy, M., Gibney, J., Pentecost, C., Wheeler, M., & Sonksen, P. (2014). Endocrine profiles in 693 elite athletes in the postcompetition setting. Clinical Endocrinology, 81(2), 294–305.

  39. Adkins-Regan, (2005), ibid. Quoted on p.4.

  40. See discussion in Oliveira (2009), ibid.

  41. Dixson, A. F., & Herbert, J. (1977). Testosterone, aggressive behavior and dominance rank in captive adult male talapoin monkeys (Miopithecus talapoin). Physiology and Behavior, 18(3), 539–543. Quoted on p. 542.

  42. See Wallen, K. (2001). Sex and context: Hormones and primate sexual motivation. Hormones and Behavior, 40(2), 339–357.

  43. Wallen (2001), ibid. Quoted on p. 340.

  44. Described in Wallen (2001), ibid. Wallen notes that additional possible contributing factors are the impoverished social environment (leaving little else to do) and the absence of social repercussions, due to the lack of a full social group.

  45. Wallen (2001), ibid. Quoted on p. 346.

  46. Adkins-Regan (2005), ibid. Quoted on p. 3.

  47. Oliveira (2009), ibid. Quoted on p. 423.

  48. See, for example, previously cited articles by R. Oliveira. This is also the principle underlying Mazur’s biosocial model; Mazur (1985), ibid.; Mazur & Booth (1998), ibid. Oliveira (2009), ibid., (p. 427) summarizes it as follows: “The social interactions in which an individual participates or to which he is exposed, influence its androgen levels, which in turn will modulate perceptive, motivational, and cognitive mechanisms that will affect his subsequent behavior in social interactions.” See also van Anders & Watson (2006), ibid.

  49. Oliveira, R. F., Almada, V. C., & Canario, A. V. M. (1996). Social modulation of sex steroid concentrations in the urine of male cichlid fish, Oreochromis mossambicus. Hormones and Behavior, 30(1), 2–12.

  50. Oliveira (2009), ibid. Quoted on p. 426.

  51. Fuxjager, M. J., Forbes-Lorman, R. M., Coss, D. J., Auger, C. J., Auger, A. P., & Marler, C. A. (2010). Winning territorial disputes selectively enhances androgen sensitivity in neural pathways related to motivation and social aggression. Proceedings of the National Academy of Sciences, 107(27), 12393–12398. See also Burmeister, S. S., Kailas
anath, V., & Fernald, R. D. (2007). Social dominance regulates androgen and estrogen receptor gene expression. Hormones and Behavior, 51(1), 164–170.

  52. Oliveira (2004), ibid. Quoted on p. 194. Note that reference is not being made here to T levels, but the ratio of 11-ketotestosterone to testosterone, indicating the conversion of the latter into the former; 11-ketotestosterone is an androgen found only in teleost fish.

  53. Ziegler, T. E., Schultz-Darken, N. J., Scott, J. J., Snowdon, C. T., & Ferris, C. F. (2005). Neuroendocrine response to female ovulatory odors depends upon social condition in male common marmosets, Callithrix jacchus. Hormones and Behavior, 47(1), 56–64. Paired non-fathers also showed T increases but the authors noted that these pairings were, at that point, short-lived.

  54. Briefly but helpfully reviewed in van Anders (2013), ibid. There are subtle differences between men and women in the relations between T and sexual behaviour and relationship orientation that, I suspect, may have to do with the effect of double standards on women’s and men’s willingness to report interest in casual sex.

  55. Mazur, A., & Michalek, J. (1998). Marriage, divorce, and male testosterone. Social Forces, 77(1), 315–330. Quoted on p. 327.

  56. Mazur & Michalek (1998), ibid. Quoted on p. 327.

  57. Gettler, L., McDade, T., Feranil, A., & Kuzawa, C. (2011). Longitudinal evidence that fatherhood decreases testosterone in human males. Proceedings of the National Academy of Sciences, 108(39), 16194–16199.

  58. Muller, M., Marlowe, F., Bugumba, R., & Ellison, P. (2009). Testosterone and paternal care in East African foragers and pastoralists. Proceedings of the Royal Society B, 276, 347–354.

  59. Helpful reviews regarding testosterone and social status and testosterone and sexuality, respectively, are provided in Hamilton, L. D., Carré, J. M., Mehta, P. H., Olmstead, N., & Whitaker, J. D. (2015). Social neuroendocrinology of status: A review and future directions. Adaptive Human Behavior and Physiology, 1(2), 202–230; van Anders (2013), ibid.