Human Nature

, Volume 29, Issue 4, pp 402–417 | Cite as

Pairs of Genetically Unrelated Look-Alikes

Further Tests of Personality Similarity and Social Affiliation
  • Nancy L. SegalEmail author
  • Brittney A. Hernandez
  • Jamie L. Graham
  • Ulrich Ettinger


Relationships of physical resemblance to personality similarity and social affiliation have generated considerable discussion among behavioral science researchers. A “twin-like” experimental design (involving genetically unrelated look-alikes, U-LAs) explores associations among resemblance in appearance, the Big Five personality traits, self-esteem, and social attraction within an evolutionary framework. The Personality for Professionals Inventory (PfPI), NEO/NEO-FFI-3, Rosenberg Self-Esteem Scale, and a Social Relationship Survey were variously completed by 45 U-LA pairs, identified from the “I’m Not a Look-Alike” project, Mentorn Media, and personal referrals. The mean U-LA intraclass correlations were negligible for all Big Five personality traits on the PfPI and NEO/NEO-FFI-3 (ri = −.02 and − .04, respectively). In contrast, mean ri values of .53 and .15 for monozygotic (MZA) and dizygotic (DZA) reared-apart twins, respectively, have been reported for these personality measures. The U-LA self-esteem correlation (ri = −.18) was also below the correlations reported for MZ and DZ reared-together twins (ri = .31 and .13, respectively). Finally, far fewer U-LAs expressed close social relationships (20%) than MZA (80%) and DZA (65%) twins. The present study extends earlier findings indicating that appearance is not meaningfully related to personality similarity and social relatedness. The criticism that MZ twins are alike in personality because their matched looks invite similar treatment by others is refuted. A more judicious interpretation is reactive genotype-environment correlation, namely that MZ twins’ similar personalities evoke similar reactions from others. MZ twins’ close social relations most likely derive from their perceptions of genetically based within-pair similarities that are lacking in U-LAs.


Twins Look-alikes Monozygotic Dizygotic Personality Self-esteem 



Canadian photographer François Brunelle and his daughter Laura made many of the U-LAs available. We also wish to thank Mentorn Media for collaborating with the first author in data collection from additional U-LA pairs for their program on look-alikes. This research was partly funded by intramural grants from California State University, Fullerton to Segal. Erika N. Becker provided research assistance.


  1. Alvarez, L. (2004). Narcissism guides mate selection: Human mates assortatively, as revealed by facial resemblance, following an algorithm of “self-seeking like.” Evolutionary Psychology, 2(1), 177–194.CrossRefGoogle Scholar
  2. Anderson, C., John, O. P., Keltner, D., & Kring, A. M. (2001). Who attains social status? Effects of personality and physical attractiveness in social groups. Journal of Personality and Social Psychology, 81(1), 116–132.CrossRefGoogle Scholar
  3. Ansell, E. B., Kurtz, J. E., & Markey, P. M. (2008). Gender differences in interpersonal complementarity within roommate dyads. Personality and Social Psychology Bulletin, 34(4), 502–512.CrossRefGoogle Scholar
  4. Bahns, A. J., Crandall, C. S., Gillath, O., & Preacher, K. J. (2017). Similarity in relationships as niche construction: Choice, stability, and influence within dyads in a free choice environment. Journal of Personality and Social Psychology, 112(2), 329–355.CrossRefGoogle Scholar
  5. Berscheid, E., Dion, K., Walster, E., & Walster, G. W. (1971). Physical attractiveness and dating choice: A test of the matching hypothesis. Journal of Experimental Social Psychology, 7(2), 173–189.CrossRefGoogle Scholar
  6. Bouchard, T. J. Jr. (1993). Genetic and environmental influences on adult personality: Evaluating the evidence. In J. Hettema & I. Deary (Eds.), Foundations of personality (pp. 15–44). Dordrecht: Kluwer.CrossRefGoogle Scholar
  7. Brechwald, W. A., & Prinstein, M. J. (2011). Beyond homophily: A decade of advances in understanding peer influence processes. Journal of Research on Adolescence, 21(1), 166–179.CrossRefGoogle Scholar
  8. Burnstein, E. (2005). Altruism and genetic relatedness. In D. M. Buss (Ed.), The handbook of evolutionary psychology (pp. 528–551). New York: John Wiley & Sons.Google Scholar
  9. Buss, D. M. (2015). Evolutionary psychology: The new science of the mind (5th ed.). New York: Routledge.CrossRefGoogle Scholar
  10. Byrne, D. (1971). The attraction paradigm. New York: Academic Press.Google Scholar
  11. CBS News (2015). “Double exposures: Photographing look-alikes.” March 8.
  12. Cicchetti, D. (2006). Development and psychopathology. In D. Cicchetti & D. J. Cohen (Eds.), Developmental psychopathology (Vol. 1, 2nd ed., pp. 1–23). New York: Wiley.Google Scholar
  13. Costa, P. T. Jr. & McCrae, R. R. (2010). NEO Inventories Professional Manual (NEO-PI-3, NEO FFI-3, NEO PI-R). Lutz: Psychological Assessment Resources.Google Scholar
  14. de Fruyt, & Willie, B. (2013). “Hey, this is not like me!” convergent validity of computerized personality reports. Revue Européene de Psychologie Appliquée, 63(5), 287–294.CrossRefGoogle Scholar
  15. Giordano, P. C. (2003). Relationships in adolescence. Annual Review of Sociology, 29(1), 257–281.CrossRefGoogle Scholar
  16. Hackman, J., Munira, S. M., Jasmin, K., & Hruschka, D. (2017). Revisiting psychological mechanisms in the anthropology of altruism. Human Nature, 28(1), 76–91.CrossRefGoogle Scholar
  17. Hamilton, W. D. (1964). The genetical evolution of social behavior, I. Journal of Theoretical Biology, 7(1), 1–16.CrossRefGoogle Scholar
  18. Hur, Y. M. (2003). Assortative mating for personality traits, educational level, religious affiliation, height, weight, and body mass index in parents of a Korean twin sample. Twin Research, 6(6), 467–470.CrossRefGoogle Scholar
  19. Ilmarinen, V., Vainikainen, M., Verkasalo, M. J., & Lönnqvist, J. (2017). Homophilous friendship assortment based on personality traits and cognitive ability in middle childhood: The moderating effect of peer network size. European Journal of Personality, 31, 208–219.CrossRefGoogle Scholar
  20. Kandel, D. B. (1978). Homophily, selection, and socialization in adolescent friendships. American Journal of Sociology, 84(2), 427–436.CrossRefGoogle Scholar
  21. Kendler, K. S., Gardner, C. O., & Prescott, C. A. (1998). A population-based twin study of self-esteem and gender. Psychological Medicine, 28(6), 1403–1409.CrossRefGoogle Scholar
  22. Kossinets, G., & Watts, D. (2009). Origins of homophily in an evolving social network. American Journal of Sociology, 115(2), 405–450.CrossRefGoogle Scholar
  23. Levine, D. (2014). Holding a mirror to their natures. New York Times, August 26, D5.Google Scholar
  24. Lieberman, D., Tooby, J., & Cosmides, L. (2007). The architecture of human kin detection. Nature, 445(7129), 727–731.CrossRefGoogle Scholar
  25. McCrae, R. R., & Costa, P. T. Jr. (2004). A contemplated revision of the NEO five-factor inventory. Personality and Individual Differences, 36(3), 587–596.CrossRefGoogle Scholar
  26. McGue, M., & Bouchard, T. J. Jr. (1984). Adjustment of twin data for the effects of age and sex. Behavior Genetics, 14(4), 325–343.CrossRefGoogle Scholar
  27. McPherson, M., Smith-Lovin, L., & Cook, J. M. (2001). Birds of a feather: Homophily in social networks. Annual Review of Sociology, 27(1), 415–444.CrossRefGoogle Scholar
  28. Naumann, L. P., Vazire, S., Rentfrow, P. J., & Gosling, S. D. (2009). Personality judgments based on physical appearance. Personality and Social Psychology Bulletin, 35(12), 1661–1671.CrossRefGoogle Scholar
  29. O’Neill, D., McAuley, C., & Loughran, H. (2016). Post-adoption sibling reunion relationships: Factors facilitating and hindering the development of sensitive relationships following reunion in adulthood. Child & Family Social Work, 21(2), 218–227.CrossRefGoogle Scholar
  30. Palmer, B. (2011). Double inanity: Twin studies are pretty much useless. Slate Magazine, August 24.
  31. Polderman, T. J., Benyamin, B., de Leeuw, C. A., Sullivan, P. F., van Bochoven, A., Visscher, P. M., & Posthuma, D. (2015). Meta-analysis of the heritability of human traits based on fifty years of twin studies. Nature Genetics, 47(7), 702–709.CrossRefGoogle Scholar
  32. Prinstein, M. J., 1970, & Dodge, K. A. (2008). Understanding peer influence in children and adolescents. New York: Guilford Press.Google Scholar
  33. Rolland, J.-P. & de Fruyt, F. (2009). PfPI questionnaire de personnalite au travail. Paris: Editions du Centre de Psychologie Appliquée (ECPA).Google Scholar
  34. Romano, A., & Balliet, D. (2017). Reciprocity outperforms conformity to promote cooperation. Psychological Science, 28(10), 1490–1502.CrossRefGoogle Scholar
  35. Rosenberg, M. (1989). Society and the adolescent image (revised ed.). Middleton: Weslyan University Press.Google Scholar
  36. Rowe, D. C. (1995). The limits of family influence: Genes, experience, and behavior (revised ed.). New York: Guilford Press.Google Scholar
  37. Rushton, J. P., & Bons, T. A. (2005). Mate choice and friendship in twins: Evidence for genetic similarity. Psychological Science, 16(7), 555–559.CrossRefGoogle Scholar
  38. Segal, N. L. (2012). Born together, reared apart: The landmark Minnesota twin study. Cambridge: Harvard University Press.CrossRefGoogle Scholar
  39. Segal, N. L. (2013). Personality similarity in unrelated look-alike pairs: Addressing a twin study challenge. Personality and Individual Differences, 54(1), 23–28.CrossRefGoogle Scholar
  40. Segal, N. L. (2017). Twin mythconceptions: False beliefs, fables, and facts about twins. San Diego: Elsevier.Google Scholar
  41. Segal, N. L., & Montoya, Y. S. (2018). Accidental brothers: The story of twins exchanged at birth and the power of nature and nurture. New York: St. Martin’s Press.Google Scholar
  42. Segal, N. L., Hershberger, N. L., & Arad, S. (2003). Meeting one’s twin: Perceived social closeness and familiarity. Evolutionary Psychology, 1(1), 70–95.CrossRefGoogle Scholar
  43. Segal, N. L., Graham, J. L., & Ettinger, U. (2013). Unrelated look-alikes: A replicated study of personality similarity and new qualitative findings on social relatedness. Personality and Individual Differences, 55(2), 169–176.CrossRefGoogle Scholar
  44. Smith, A., Pedersen, E. J., Forster, D. E., McCullough, M. E., & Lieberman, D. (2017). Cooperation: The roles of interpersonal value and gratitude. Evolution and Human Behavior, 38(6), 695–703.CrossRefGoogle Scholar
  45. Voracek, M., Dressler, S. G., & Manning, J. T. (2007). Evidence for assortative mating on digit ratio (2D:4D), a biomarker for prenatal androgen exposure. Journal of Biosocial Science, 39(4), 599–612.CrossRefGoogle Scholar
  46. Youyou, W., Stillwell, D., Schwartz, H. A., & Kosinski, M. (2017). Birds of a feather do flock together: Behavior-based personality-assessment method reveals personality similarity among couples and friends. Psychological Science, 28(3), 276–284.CrossRefGoogle Scholar
  47. Zietsch, B. P., Verweij, K. J., Heath, A. C., & Martin, N. G. (2011). Variation in human mate choice: Simultaneously investigating heritability, parental influence, sexual imprinting, and assortative mating. The American Naturalist, 177(5), 605–616.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  • Nancy L. Segal
    • 1
    Email author
  • Brittney A. Hernandez
    • 2
  • Jamie L. Graham
    • 3
  • Ulrich Ettinger
    • 4
  1. 1.Department of PsychologyCalifornia State UniversityFullertonUSA
  2. 2.Department of EducationUniversity of ConnecticutStorrsUSA
  3. 3.Department of Human Development & Family SciencesUniversity of TexasAustinUSA
  4. 4.Institut für PsychologieUniversität BonnBonnGermany

Personalised recommendations