Skip to main content

Digit ratio (2D:4D) and social integration: An effect of prenatal sex hormones


The position people occupy in their social and professional networks is related to their social status and has strong effects on their access to social resources. While attainment of particular positions is driven by behavioral traits, many biological factors predispose individuals to certain behaviors and motivations. Prior work on exposure to fetal androgens (measured by second-to-fourth digit ratio, 2D:4D) shows that it correlates with behaviors and traits related to social status, which might make people more socially integrated. However, it also predicts certain anti-social behaviors and disorders associated with lower socialization. We explore whether 2D:4D correlates with network position later in life and find that individuals with low 2D:4D become more central in their social environment. Interestingly, low 2D:4D males are more likely to exhibit high betweenness centrality (they connect separated parts of the social structure), while low 2D:4D females are more likely to exhibit high in-degree centrality (more people name them as friends). These gender-specific differences are reinforced by transitivity (the likelihood that one's friends are also friends with one another): neighbors of low 2D:4D men tend not to know each other; the contrary is observed for low 2D:4D women. Our results suggest that biological predispositions influence the organization of human societies and that exposure to prenatal androgens influences different status seeking behaviors in men and women.

Hide All
Bailey A. A., & Hurd P. L. (2005a). Finger length ratio (2D: 4D) correlates with physical aggression in men but not in women. Biological Psychology, 68 (3), 215222.
Bailey A. A., & Hurd P. L. (2005b). Depression in men is associated with more feminine finger length ratios. Personality and Individual Differences, 39 (4), 829836.
Bala V., & Goyal S. (2000). A noncooperative model of network formation. Econometrica, 68 (5), 11811229.
Barabási A. L., & Albert R. (1999). Emergence of scaling in random networks. Science, 286 (5439), 509512.
Baron-Cohen S., Knickmeyer R. C., & Belmonte M. K. (2005). Sex differences in the brain: Implications for explaining autism. Science, 310 (5749), 819823.
Booth A., Johnson D. R., & Granger D. A. (1999). Testosterone and men's health. Journal of Behavioral Medicine, 22 (1), 119.
Brañas-Garza P., Cobo-Reyes R., Espinosa M. P., Jiménez N., Kovářík J., & Ponti G. (2010). Altruism and social integration. Games and Economic Behavior, 69 (2), 249257.
Brañas-Garza P., Galizzi M. M., & Nieboer J. (forthcoming). Experimental and Self-Reported Measures of Risk Taking and Digit Ratio: Evidence from a Large, Systematic Study. International Economic Review.
Brañas-Garza P., Kovářík J., & Neyse L. (2013). Second-to-fourth digit ratio has a non-monotonic impact on altruism. PloS ONE, 8 (4), 110.
Breedlove S., & Hampson E. (2002) in Behavioral endocrinology, Becker J., Breedlove S., Crews D., & McCarthy M. (Eds.) (2nd ed.) (pp. 75114). Cambridge: MIT Press.
Burt R. S. (2004). Structural holes and good ideas. American Journal of Sociology, 110 (2), 349399.
Burt R. S., Jannotta J. E., & Mahoney J. T. (1998). Personality correlates of structural holes. Social Networks, 20 (1), 6387.
Carré J. M., & Olmstead N. A. (2015). Social neuroendocrinology of human aggression: Examining the role of competition-induced testosterone dynamics. Neuroscience, 286, 171186.
Carré J. M., Putnam S. K. & McCormick C. M. (2009). Testosterone responses to competition predict future aggressive behaviour at a cost to reward in men. Psychoneuroendocrinology, 34 (4), 561570.
Charness G., & Gneezy U. (2012). Strong evidence for gender differences in risk taking. Journal of Economic Behavior & Organization, 83 (1), 5058.
Christakis N. A., & Fowler J. H. (2014). Friendship and natural selection. Proceedings of the National Academy of Sciences, 111 (Supplement 3), 1079610801.
Coates J. M., Gurnell M., & Rustichini A. (2009). Second-to-fourth digit ratio predicts success among high-frequency financial traders. Proceedings of the National Academy of Sciences, 106 (2), 623628.
Coleman J. S. (1988). Social capital in the creation of human capital. American Journal of Sociology, 94, S95S120.
Collins R. (2009). The sociology of philosophies. Cambridge: Harvard University Press.
Croson R., & Gneezy U. (2009). Gender differences in preferences. Journal of Economic Literature, 47 (2), 448474.
Eagly A. H. (2013). Sex differences in social behavior: A social-role interpretation. London: Psychology Press.
Espinosa M. P. & Kovářík J. (2015). Prosocial behavior and gender. Frontiers in Behavioral Neuroscience, 9, 88.
Fink B., Neave N., & Manning J. T. (2003). Second to fourth digit ratio, body mass index, waist-to-hip ratio, and waist-to-chest ratio: Their relationships in heterosexual men and women. Annals of Human Biology, 30 (6), 728738.
Fowler J. H., Dawes C. T., & Christakis N. A. (2009). Model of genetic variation in human social networks. Proceedings of the National Academy of Sciences, 106 (6), 17201724.
Freeman L. C. (1977). A set of measures of centrality based on betweenness. Sociometry, 40 (1), 35.
Goy R. W. & McEwen B. S. (1979). Sexual differentiation of the brain. Boston: MIT Press.
Granovetter M. (1985). Economic action and social structure: The problem of embeddedness. American Journal of Sociology, 91 (3), 481510.
Granovetter M. S. (1973). The strength of weak ties. American Journal of Sociology, 78 (6), 3601380.
Hopp R. N., de Moraes J. P., & Jorge J. (2012). Digit ratio and academic performance in dentistry students. Personality and Individual Differences, 52 (5), 643646.
Jackson M. O. (2010). Social and economic networks. Princeton: Princeton University Press.
Kalish Y., & Robins G. (2006). Psychological predispositions and network structure: The relationship between individual predispositions, structural holes and network closure. Social Networks, 28 (1), 5684.
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 (5).
Kovářík J., Brañas-Garza P., Cobo-Reyes R., Espinosa M. P., Jiménez N., & Ponti G. (2012). Prosocial norms and degree heterogeneity in social networks. Physica A: Statistical Mechanics and its Applications, 391 (3), 849853.
Kovářík J. & van der Leij M. J. (2015). Risk aversion and social networks. Review of Network Economics, 13 (2), pp. 121155.
Lin N. (1999). Social networks and status attainment. Annual Review of Sociology, 25 (1), 467487.
Lutchmaya S., Baron-Cohen S., & Raggatt P. (2002). Foetal testosterone and eye contact in 12-month-old human infants. Infant Behavior and Development, 25 (3), 327335.
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 (1), 2328.
Manning J. T. (2002). Digit ratio, Rutgers: Rutgers University Press.
Manning J. T., Baron-Cohen S., Wheelwright S., & Sanders G. (2001). The 2nd to 4th digit ratio and autism. Developmental Medicine & Child Neurology, 43 (3), 160164.
Manning J. T., & Bundred P. E. (2000). The ratio of 2nd to 4th digit length: A new predictor of disease predisposition? Medical Hypotheses, 54 (5), 855857.
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 (4), 451461.
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 (11), 30003004.
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 (1), 6169.
McPherson M., Smith-Lovin L., & Cook J. M. (2001). Birds of a feather: Homophiliy in social networks. Annual Review of Sociology, 27 (1), 415444.
Milne E., White S., Campbell R., Swettenham J., Hansen P., & Ramus F. (2006). Motion and form coherence detection in autistic spectrum disorder: Relationship to motor control and 2: 4 digit ratio. Journal of Autism and Developmental Disorders, 36 (2), 225237.
Millet K. (2009). Low second-to-fourth-digit ratio might predict success among high-frequency financial traders because of a higher need for achievement. Proceedings of the National Academy of Sciences, 106 (11), pnas-0900396106.
Newman M. (2010). Networks: An introduction. Oxford: Oxford University Press.
Neyse L. & Brañas-Garza P. (2014).Digit ratio measurement guide. Munich Repository Archive, 54134.
Padgett J. F., & Ansell C. K. (1993). Robust action and the rise of the medici, 1400–1434. American Journal of Sociology, 98 (6), 12591319.
Paul S. N., Kato B. S., Hunkin J. L., Vivekanandan S., & Spector T. D. (2006). The big finger: The second to fourth digit ratio is a predictor of sporting ability in women. British Journal of Sports Medicine, 40 (12), 981983.
Roney J. R., & Maestripieri D. (2004). Relative digit lengths predict men's behavior and attractiveness during social interactions with women. Human Nature, 15 (3), 271282.
Sluming V. A., & Manning J. T. (2000). Second to fourth digit ratio in elite musicians. Evolution and Human Behavior, 21 (1), 19.
Stanton S. J., & Schultheiss O. C. (2009). The hormonal correlates of implicit power motivation. Journal of Research in Personality, 43 (5), 942949.
Tobet S., & Baum M. (1987) Role for prenatal estrogen in the development of masculine sexual behavior in the male ferret. Hormonal Behavior, 21 (4), 419429.
Van Honk J., Montoya E. R., Bos P. A., Van Vugt M., & Terburg D. (2012). New evidence on testosterone and cooperation. Nature, 485 (7399), 45.
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 (8), 34483452.
Vega-Redondo F. (2007). Complex social networks. Cambridge: Cambridge University Press.
Voracek M., & Loibl L. M. (2009). Scientometric analysis and bibliography of digit ratio (2D: 4D) research, 1998–2008. Psychological Reports, 104 (3), 922956.
Watts D. J., & Strogatz S. H. (1998). Collective dynamics of ‘small-world’ networks. Nature, 393 (6684), 440442.
Zaheer A., & Bell G. G. (2005). Benefiting from network position: Firm capabilities, structural holes, and performance. Strategic Management Journal, 26 (9), 809825.
Zheng Z., & Cohn M. J. (2011). Developmental basis of sexually dimorphic digit ratios. Proceedings of the National Academy of Sciences, 108 (39), 1628916294.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Network Science
  • ISSN: 2050-1242
  • EISSN: 2050-1250
  • URL: /core/journals/network-science
Please enter your name
Please enter a valid email address
Who would you like to send this to? *


Type Description Title
Supplementary Materials

Kovářík supplementary material
Kovářík supplementary material

 PDF (1.2 MB)
1.2 MB


Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 48 *
Loading metrics...

Abstract views

Total abstract views: 339 *
Loading metrics...

* Views captured on Cambridge Core between 4th July 2017 - 14th December 2017. This data will be updated every 24 hours.