ISSN : 1229-0653
Recently, there has been an increased interest in the relationship between 2D:4D ratio (second-to-fourth digit ratio) and social behaviors. It is because 2D:4D can be used to explore a potential biological basis (the effect of prenatal testosterone) of individual differences in social behavior. Prenatal testosterone has organizational effects on brain development and finger length pattern, as well as permanent influence on behavior in later life. Low 2D:4D indicates high level of testosterone relative to estrogen in utero. If prenatal testosterone plays an important role in early brain development, digit ratio and later behavior, social behavior should be related to 2D:4D. In addition, if prenatal testosterone shapes the neural networks underlying social behaviors, these networks may be able to be activated by specific stimuli (e.g., social threat, testosterone administration) that provoke testosterone-dependent behaviors, and social behaviors expressed in response to those stimuli may be modulated by 2D:4D. Therefore, this review outlines research findings of the relationship between 2D:4D and social behaviors (e.g., social cooperation, risk taking, impulsivity, and aggression) using economic games (e.g., Trust game, Public goods game, Ultimatum game, etc) with a main focus on the role of 2D:4D dynamics in modulating social behaviors in response to certain stimuli. Studies have shown that 2D:4D affects on social decision making. Furthermore, prenatal testosterone may preprogram the neural mechanisms underlying social behaviors, and it may selectively modifies neural processing to facilitate or inhibit social behaviors in response to environmental or physiological cues.
Adler, N. E., Epel, E. S., Castellazzo, G., & Ickovics, J. R. (2000). Relationship of subjective and objective social status with psychological and physiological functioning: preliminary data in healthy white women. Health Psychology, 19, 586-592.
Anderson, T. (2012). Comparing risk-taking and digit ratio (2D: 4D) in offenders and non-offenders. The Plymouth Student Scientist, 5, 105-120.
Archer, J. (2004). Sex differences in aggression in real-world settings: A meta-analytic review. Review of General Psychology, 8, 291-322.
Arnold, A. P., & Breedlove, S. M. (1985). Organizational and activational effects of sex steroids on brain and behavior: a reanalysis. Hormones and Behavior, 19, 469-498.
Austin, E. J., Manning, J. T., McInroy, K., & Mathews, E. (2002). A preliminary investigation of the associations between personality, cognitive ability and digit ratio. Personality and Individual Differences, 33, 1115-1124.
Bailey, A. A., & Hurd, P. L. (2005). Finger length ratio (2D: 4D) correlates with physical aggression in men but not in women. Biological Psychology, 68, 215-222.
Benderlioglu, Z., & Nelson, R. J. (2004). Digit length ratios predict reactive aggression in women, but not in men. Hormones and Behavior, 46, 558-564.
Berenbaum, S. A., Bryk, K. K., Nowak, N., Quigley, C. A., & Moffat, S. (2009). Fingers as a marker of prenatal androgen exposure. Endocrinology, 150, 5119-5124.
Berenbaum, S. A., & Resnick, S. M. (1997). Early androgen effects on aggression in children and adults with congenital adrenal hyperplasia. Psychoneuroendocrinology, 22, 505-515.
Bescos, R., Esteve, M., Porta, J., Mateu, M., Irurtia, A., & Voracek, M. (2009). Prenatal programming of sporting success: Associations of digit ratio (2D: 4D), a putative marker for prenatal androgen action, with world rankings in female fencers. Journal of Sports Sciences, 27, 625-632.
Bos, P. A., Hermans, E. J., Ramsey, N. F., & van Honk, J. (2012). The neural mechanisms by which testosterone acts on interpersonal trust. Neuro Image, 61, 730-737.
Bos, P. A., Terburg, D., & van Honk, J. (2010). Testosterone decreases trust in socially naive humans. Proceedings of the National Academy of Sciences, 107, 9991-9995.
Breedlove, S. M. (1994). Sexual differentiation of the human nervous system. Annual Review of Psychology, 45, 389-418.
Breedlove, S. M. (2010). Minireview: Organizational hypothesis: instances of the fingerpost. Endocrinology, 151, 4116-4122.
Brown, W. M., Hines, M., Fane, B. A., & Breedlove, S. M. (2002). Masculinized finger length patterns in human males and females with congenital adrenal hyperplasia. Hormones and Behavior, 42, 380-386.
Buck, J. J., Williams, R. M., Hughes, I. A., & Acerini, C. L. (2003). In‐utero androgen exposure and 2nd to 4th digit length ratio- comparisons between healthy controls and females with classical congenital adrenal hyperplasia. Human Reproduction, 18, 976-979.
Buss, D. M. (2004). Evolutionary Psychology: the new science of the mind. Pearson Education, Inc.
Butovskaya, M. L., Vasilyev, V. A., Lazebny, O. E., Burkova, V. N., Kulikov, A. M., Mabulla, A., ... & Ryskov, A. P. (2012). Aggression, digit ratio, and variation in the androgen receptor, serotonin transporter, and dopamine D4 receptor genes in African Foragers: The Hadza. Behavior Genetics, 42, 647-662.
Carre, J. M., McCormick, C. M., & Hariri, A. R. (2011). The social neuroendocrinology of human aggression. Psychoneuroendocrinology, 36, 935-944.
Chapman, E., Baron-Cohen, S., Auyeung, B., Knickmeyer, R., Taylor, K., & Hackett, G. (2006). Fetal testosterone and empathy: Evidence from the empathy quotient (EQ) and the “reading the mind in the eyes” test. Social Neuroscience, 1, 135-148.
Coyne, S. M., Manning, J. T., Ringer, L., & Bailey, L. (2007). Directional asymmetry (right–left differences) in digit ratio (2D: 4D) predict indirect aggression in women. Personality and Individual Differences, 43, 865-872.
Crewther, B. T., Cook, C., Cardinale, M., Weatherby, R. P., & Lowe, T. (2011). Two emerging concepts for elite athletes. Sports Medicine, 41, 103-123.
Dabbs, J. M., & Dabbs, M. G. (2000). Heroes, rogues, and lovers: Testosterone and behavior. McGraw-Hill.
De Neys, W., Hopfensitz, A., & Bonnefon, J. F. (2013). Low second-to-fourth digit ratio predicts indiscriminate social suspicion, not improved trustworthiness detection. Biology Letters, 9, 20130037.
de Wit, H., Flory, J. D., Acheson, A., McCloskey, M., & Manuck, S. B. (2007). IQ and nonplanning impulsivity are independently associated with delay discounting in middle-aged adults. Personality and Individual Differences, 42, 111-121.
Eisenegger, C., Haushofer, J., & Fehr, E. (2011). The role of testosterone in social interaction. Trends in Cognitive Sciences, 15, 263-271.
Eisenegger, C., Naef, M., Snozzi, R., Heinrichs, M., & Fehr, E. (2010). Prejudice and truth about the effect of testosterone on human bargaining behaviour. Nature, 463, 356-359.
Elias, M. (1981). Serum cortisol, testosterone, and testosterone‐binding globulin responses to competitive fighting in human males. Aggressive Behavior, 7, 215-224.
Falter, C. M., Arroyo, M., & Davis, G. J. (2006). Testosterone: Activation or organization of spatial cognition?. Biological Psychology, 73, 132-140.
Folstad, I., & Karter, A. J. (1992). Parasites, bright males and the immunocompetence handicap. American Naturalist, 139, 603-622.
Gallup, A. C., White, D. D., & Gallup, G. G. (2007). Handgrip strength predicts sexual behavior, body morphology, and aggression in male college students. Evolution and Human Behavior, 28, 423-429.
Garbarino, E., Slonim, R., & Sydnor, J. (2011). Digit ratios (2D: 4D) as predictors of risky decision making for both sexes. Journal of Risk and Uncertainty, 42, 1-26.
Geschwind, N., & Galaburda, A. M. (1985). Cerebral lateralization: Biological mechanisms, associations, and pathology: I. A hypothesis and a program for research. Archives of Neurology, 42, 428-459.
Hampson, E., Ellis, C. L., & Tenk, C. M. (2008). On the relation between 2D:4D and sex dimorphic personality traits. Archives of Sexual Behavior, 37, 133-144.
Honekopp, J., Bartholdt, L., Beier, L., & Liebert, A. (2007). Second to fourth digit length ratio (2D:4D) and adult sex hormone levels: New data and a meta-analytic review. Psychoneuroendocrinology, 32, 313-321.
Honekopp, J., Manning, J. T., & Muller, C. (2006). Digit ratio (2D:4D) and physical fitness in males and females: Evidence for effects of prenatal androgens on sexually selected traits. Hormones and Behavior, 49, 545-549.
Honekopp, J., & Schuster, M. (2010). A meta-analysis on 2D:4D and athletic prowess: Substantial relationships but neither hand out-predicts the other. Personality and Individual Differences, 48, 4-10.
Honekopp, J., & Watson, S. (2011). Meta-analysis of the relationship between digit-ratio 2D: 4D and aggression. Personality and Individual Differences, 51, 381-386.
Josephs, R. A., Sellers, J. G., Newman, M. L., & Mehta, P. H. (2006). The mismatch effect: when testosterone and status are at odds. Journal of Personality and Social Psychology, 90, 999-1013.
Joyce, C. W., Kelly, J. C., Chan, J. C., Colgan, G., O’Briain, D., Mc Cabe, J. P., & Curtin, W. (2013). Second to fourth digit ratio confirms aggressive tendencies in patients with boxers fractures. Injury, 44, 1636-1639.
Kilduff, L., Cook, C. J., Bennett, M., Crewther, B., Bracken, R. M., & Manning, J. (2013). Right-left digit ratio (2D: 4D) predicts free testosterone levels associated with a physical challenge. Journal of Sports Sciences, 31, 677-683.
Kilduff, L. P., Hopp, R. N., Cook, C. J., Crewther, B. T., & Manning, J. T. (2013). Digit ratio (2D: 4D), aggression, and testosterone in men exposed to an aggressive video stimulus. Evolutionary Psychology, 11, 953-964.
Kirby, K. N., Petry, N. M., & Bickel, W. K. (1999). Heroin addicts have higher discount rates for delayed rewards than non-drug-using controls. Journal of Experimental Psychology: General, 128, 78-87.
Lejuez, C. W., Read, J. P., Kahler, C. W., Richards, J. B., Ramsey, S. E., Stuart, G. L., ... & Brown, R. A. (2002). Evaluation of a behavioral measure of risk taking: the Balloon Analogue Risk Task (BART). Journal of Experimental Psychology: Applied, 8, 75-84.
Lippa, R. A. (2003). Are 2D: 4D finger-length ratios related to sexual orientation? Yes for men, no for women. Journal of Personality and Social Psychology, 85, 179-188.
Lombardo, M. V., Ashwin, E., Auyeung, B., Chakrabarti, B., Lai, M. C., Taylor, K., ... & Baron-Cohen, S. (2012). Fetal programming effects of testosterone on the reward system and behavioral approach tendencies in humans. Biological Psychiatry, 72, 839-847.
Lucas, M., & Koff, E. (2010). Delay discounting is associated with the 2D: 4D ratio in women but not men. Personality and Individual Differences, 48, 182-186.
Luengo, M. A., Carrillo-De-La-Pena, M. T., Otero, J. M., & Romero, E. (1994). A short-term longitudinal study of impulsivity and antisocial behavior. Journal of Personality and Social Psychology, 66, 542.
Lutchmaya S, Baron-Cohen S, Raggatt P, Knickmeyer R, Manning, J. T. (2004). 2nd to 4th digit ratios, fetal testosterone and estradiol. Early Human Development, 77, 23-28.
Malas, M. A., Dogan, S., Hilal Evcil, E., & Desdicioglu, K. (2006). Fetal development of the hand, digits and digit ratio (2D: 4D). Early Human Development, 82, 469-475.
Manning, J. T. (2002). Digit ratio: A pointer to fertility, behavior, and health. New Jersey: Rutgers University Press.
Manning, J. T. (2011). Resolving the role of prenatal sex steroids in the development of digit ratio. Proceedings of the National Academy of Sciences, 108, 16143-16144.
Manning, J. T., Bundred, P. E., Newton, D. J., & Flanagan, B. F. (2003). The second to fourth digit ratio and variation in the androgen receptor gene. Evolution and Human Behavior, 24, 399-405.
Manning, J. T., & Fink, B. (2008). Digit ratio (2D: 4D), dominance, reproductive success, asymmetry, and sociosexuality in the BBC Internet Study. American Journal of Human Biology, 20, 451-461.
Manning, J., Kilduff, L., Cook, C., Crewther, B., & Fink, B. (2014). Digit Ratio (2D: 4D): A biomarker for prenatal sex steroids and adult sex steroids in challenge situations. Frontiers in Endocrinology, 5, 9.
Manning, J. T., Scutt, D., Wilson, J., & Lewis-Jones, D. I. (1998). The ratio of 2nd to 4th digit length: a predictor of sperm numbers and concentrations of testosterone, luteinizing hormone and oestrogen. Human Reproduction, 13, 3000-3004.
Manning, J. T., & Taylor, R. P. (2001). Second to fourth digit ratio and male ability in sport: implications for sexual selection in humans. Evolution and Human Behavior, 22, 61-69.
Mayer, R. C., Davis, J. H., & Schoorman, F. D. (1995). An integrative model of organizational trust. Academy of Management Review, 20, 709-734.
Mazur, A. (2005). Biosociology of dominance and deference. Rowman & Littlefield Publishers.
Mazur, A., & Booth, A. (1998). Testosterone and dominance in men. Behavioral and Brain Sciences, 21, 353-363.
McIntyre, M. H., Barrett, E. S., McDermott, R., Johnson, D. D., Cowden, J., & Rosen, S. P. (2007). Finger length ratio (2D: 4D) and sex differences in aggression during a simulated war game. Personality and Individual Differences, 42, 755-764.
McIntyre, M. H., Ellison, P. T., Lieberman, D. E., Demerath, E., & Towne, B. (2005). The development of sex differences in digital formula from infancy in the Fels Longitudinal Study. Proceedings of the Royal Society B: Biological Sciences, 272, 1473-1479.
Mehta, P. H., & Beer, J. (2010). Neural mechanisms of the testosterone-aggression relation: The role of orbitofrontal cortex. Journal of Cognitive Neuroscience, 22, 2357-2368.
Millet, K., & Dewitte, S. (2006). Second to fourth digit ratio and cooperative behavior. Biological Psychology, 71, 111-115.
Millet, K., & Dewitte, S. (2007). Digit ratio (2D: 4D) moderates the impact of an aggressive music video on aggression. Personality and Individual Differences, 43, 289-294.
Millet, K., & Dewitte, S. (2008). A subordinate status position increases the present value of financial resources for low 2D: 4D men. American Journal of Human Biology, 20, 110-115.
Millet, K., & Dewitte, S. (2009). The presence of aggression cues inverts the relation between digit ratio (2D: 4D) and prosocial behaviour in a dictator game. British Journal of Psychology, 100, 151-162.
Moll, J., & de Oliveira-Souza, R. (2007). Moral judgments, emotions and the utilitarian brain. Trends in Cognitive Sciences, 11, 319-321.
Montoya, E. R., Terburg, D., Bos, P. A., Will, G. J., Buskens, V., Raub, W., & van Honk, J. (2013). Testosterone administration modulates moral judgments depending on second-to-fourth digit ratio. Psychoneuroendocrinology, 38, 1362- 1369.
Moore, T., Quinter, C., & Freeman, L. M. (2005). Lack of correlation between 2D: 4D ratio and assertiveness in college age women. Personality and Individual Differences, 39, 115-121.
Muehlenbein, M. P., & Bribiescas, R. G. (2005). Testosterone‐mediated immune functions and male life histories. American Journal of Human Biology, 17, 527-558.
Neave, N., Laing, S., Fink, B., & Manning, J. T. (2003). Second to fourth digit ratio, testosterone, and perceived male dominance. Proceedings of the Royal Society of London Series B, Biological Sciences, 270, 2167-2172.
Neave, N., & Wolfson, S. (2003). Testosterone, territoriality, and the ‘home advantage’. Physiology & Behavior, 78, 269-275.
Okten, A., Kalyoncu, M., & Yaris, N. (2002). The ratio of second- and fourth-digit lengths and congenital adrenal hyperplasia due to 21-hydroxylase deficiency. Early Human Development, 70, 47-54.
Oliveira, R. F. (2009). Social behavior in context: hormonal modulation of behavioral plasticity and social competence. Integrative and Comparative Biology, 49, 423-440.
Page, K. M., & Nowak, M. A. (2001). A generalized adaptive dynamics framework can describe the evolutionary Ultimatum Game. Journal of Theoretical Biology, 209, 173-179.
Pietrzak, R. H., & Petry, N. M. (2005). Antisocial personality disorder is associated with increased severity of gambling, medical, drug and psychiatric problems among treatment seeking pathological gamblers. Addiction, 100, 1183- 1193.
Putz, D. A., Gaulin, S. J. C., Sporter, R. J., & McBurney, D. H. (2004). Sex hormones and finger length: what does 2D:4D indicate? Evolution and Human Behavior, 25, 182-199.
Ronay, R., & Galinsky, A. D. (2011). Lex talionis: Testosterone and the law of retaliation. Journal of Experimental Social Psychology, 47 ,702-705.
Ronay, R., & von Hippel, W. (2010). Power, testosterone, and risk‐taking. Journal of Behavioral Decision Making, 23, 473-482.
Sanchez-Pages, S., & Turiegano, E. (2010). Testosterone, facial symmetry and cooperation in the prisoners' dilemma. Physiology & Behavior, 99, 355-361.
Sapienza, P., Zingales, L., & Maestripieri, D. (2009). Gender differences in financial risk aversion and career choices are affected by testosterone. Proceedings of the National Academy of Sciences, 106, 15268-15273.
Senju, A., & Johnson, M. H. (2009). The eye contact effect: mechanisms and development. Trends in Cognitive Sciences, 13, 127-134.
Sim, K. (2013). The relationship between sex-typical body shape and quality indicators. Journal of Social, Evolutionary, and Cultural Psychology, 7, 97-120.
Stenstrom, E., Saad, G., Nepomuceno, M. V., & Mendenhall, Z. (2011). Testosterone and domain-specific risk: Digit ratios (2D:4D and rel2) as predictors of recreational, financial, and social risk-taking behaviors. Personality and Individual Differences, 51, 412-416.
Terburg, D., & van Honk, J. (2013). Approach- avoidance versus dominance-submissiveness: A multilevel neural framework on how testosterone promotes social status. Emotion Review, 5, 296-302.
van Anders, S. M., Vernon, P. A., & Wilbur, C. J. (2006). Finger-length ratios show evidence of prenatal hormone-transfer between opposite-sex twins. Hormones and Behavior, 49, 315-319.
van den Bergh, B., & Dewitte, S. (2006). Digit ratio (2D: 4D) moderates the impact of sexual cues on men's decisions in ultimatum games. Proceedings of the Royal Society B: Biological Sciences, 273, 2091-2095.
van Honk, J., Montoya, E. R., Bos, P. A., van Vugt, M., & Terburg, D. (2012). New evidence on testosterone and cooperation. Nature, 485, E4-E5.
van Honk, J., & Schutter, D. J. (2007). Testosterone reduces conscious detection of signals serving social correction implications for antisocial behavior. Psychological Science, 18, 663-667.
van Honk, J., Schutter, D. J., Bos, P. A., Kruijt, A. W., Lentjes, E. G., & Baron-Cohen, S. (2011). Testosterone administration impairs cognitive empathy in women depending on second-to-fourth digit ratio. Proceedings of the National Academy of Sciences, 108, 3448-3452.
van Honk, J., Terburg, D., & Bos, P. A. (2011). Further notes on testosterone as a social hormone. Trends in Cognitive Sciences, 15, 291-292.
van Wingen, G., Mattern, C., Verkes, R. J., Buitelaar, J., & Fernández, G. (2010). Testosterone reduces amygdala-orbitofrontal cortex coupling. Psychoneuroendocrinology, 35, 105-113.
Vermeersch, H., T'Sjoen, G., Kaufman, J. M., & Vincke, J. (2008). 2d: 4d, sex steroid hormones and human psychological sex differences. Hormones and Behavior, 54, 340-346.
Voracek, M., & Dressler, S. G. (2006). Lack of correlation between digit ratio (2D: 4D) and Baron-Cohen’s “Reading the Mind in the Eyes” test, empathy, systemising, and autism-spectrum quotients in a general population sample. Personality and Individual Differences, 41, 1481-1491.
Voracek, M., & Loibl, L. M. (2009). Scientometric analysis and bibliography of digit ratio (2D:4D) research, 1998-2008 1, 2. Psychological Reports, 104, 922-956.
Wilson, M., & Daly, M. (2004). Do pretty women inspire men to discount the future?. Proceedings of the Royal Society of London. Series B: Biological Sciences, 271 (Suppl4), S177-S179.