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Social factor, barrier 3 of 6

In-group bias

Social identity theory (Tajfel and Turner, 1979) explains favoritism toward one's own group and suspicion of outsiders.

Evidence

  • Favoritism. A meta-analysis of 212 studies found people cooperate more with members of their own group than with outsiders (d = 0.32), and that this reflects favoritism toward the in-group more than hostility toward the out-group (Balliet, Wu, and De Dreu, 2014).
  • Strength. The meta-analysis is rated B provisionally, and the theory is rated A for in-group favoritism and B for the full theory.

Note: People with higher science literacy defended their group's position on climate risk (Kahan et al., 2012, see the cultural factor).

Proposed and experimental methods

Methods that are proposed, under trial, approved in some places, or tried and then failed. Each shows a stage label and an evidence rating. A stage label shows how far a method has progressed, not whether it works. The stage labels are explained on the social factor page.

  • Cooperative contact in mixed teams (Large trial, B). In India, men randomly placed on mixed-caste cricket teams formed more cross-caste friendships and showed less own-caste favoritism, while being randomly matched against other castes as opponents generally reduced cross-caste interaction (Lowe, 2021). In post-ISIS Iraq, displaced Christians randomly assigned to soccer teams that included Muslims were more likely to vote for a Muslim player for a sportsmanship award, register for a mixed team next season, and train with Muslims 6 months later, but behavior in other settings and attitudes did not change consistently (Mousa, 2020).
  • Skills training in mixed classes (Large trial, B). In Kaduna, Nigeria, 849 Christian and Muslim young men were randomized into a vocational program in mixed or single-religion classes with sixteen weeks of positive contact. Prejudice did not change, but men in mixed classes discriminated less against the other group than men in single-religion classes, mainly because single-religion classes increased discrimination (Scacco and Warren, 2018).
  • Intergroup contact programs, re-evaluated (In wide use, B). See "Cultural value differences" in the cultural factors for the meta-analysis of 27 randomized contact studies and its limits for racial and ethnic prejudice.
  • Mixing income groups in schools (Approved but not scaled, B). Using a natural experiment in Delhi schools, richer students who had poorer classmates became more prosocial, generous, and egalitarian, discriminated less against poor students, and were more willing to socialize with them, with mixed and modest academic effects on the richer students (Rao, 2019).
  • Not shown to help: one-off diversity training and brief implicit bias exercises (In wide use, B). In a preregistered field experiment with 3,016 employees of a global organization, a brief online diversity training changed attitudes but not behavior among groups whose attitudes were least supportive of women (Chang et al., 2019). In two studies with 6,321 participants, nine interventions reduced implicit racial preferences immediately, but none were effective after a delay of several hours to several days and none changed explicit preferences (Lai et al., 2016).

Sources cited on this page

  1. Balliet, D., Wu, J., & De Dreu, C. K. W. (2014). Ingroup favoritism in cooperation: a meta-analysis. Psychological Bulletin, 140(6), 1556-1581. Semantic Scholar A Strong
  2. Tajfel, H., & Turner, J. C. (1979). An integrative theory of intergroup conflict. In W. G. Austin and S. Worchel (Eds.), The Social Psychology of Intergroup Relations (pp. 33-47). Monterey, CA: Brooks/Cole. A Strong: for in-group favoritism, B for the full theory
  3. Chang, E. H., Milkman, K. L., Gromet, D. M., Rebele, R. W., Massey, C., Duckworth, A. L., et al. (2019). The mixed effects of online diversity training. Proceedings of the National Academy of Sciences, 116(16), 7778-7783. link B Moderate
  4. Lai, C. K., Skinner, A. L., Cooley, E., Murrar, S., Brauer, M., Devos, T., et al. (2016). Reducing implicit racial preferences: II. Intervention effectiveness across time. Journal of Experimental Psychology: General, 145(8), 1001-1016. link B Moderate
  5. Rao, G. (2019). Familiarity does not breed contempt: Generosity, discrimination, and diversity in Delhi schools. American Economic Review, 109(3), 774-809. link B Moderate
  6. Scacco, A., & Warren, S. S. (2018). Can social contact reduce prejudice and discrimination? Evidence from a field experiment in Nigeria. American Political Science Review, 112(3), 654-677. link B Moderate

Every source for this factor is listed on the social factor page.