Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Neural evidence for inequality-averse social preferences

Abstract

A popular hypothesis in the social sciences is that humans have social preferences to reduce inequality in outcome distributions because it has a negative impact on their experienced reward1,2,3. Although there is a large body of behavioural and anthropological evidence consistent with the predictions of these theories1,4,5,6, there is no direct neural evidence for the existence of inequality-averse preferences. Such evidence would be especially useful because some behaviours that are consistent with a dislike for unequal outcomes could also be explained by concerns for social image7 or reciprocity8,9, which do not require a direct aversion towards inequality. Here we use functional MRI to test directly for the existence of inequality-averse social preferences in the human brain. Inequality was created by recruiting pairs of subjects and giving one of them a large monetary endowment. While both subjects evaluated further monetary transfers from the experimenter to themselves and to the other participant, we measured neural responses in the ventral striatum and ventromedial prefrontal cortex, two areas that have been shown to be involved in the valuation of monetary and primary rewards in both social and non-social contexts10,11,12,13,14. Consistent with inequality-averse models of social preferences, we find that activity in these areas was more responsive to transfers to others than to self in the ‘high-pay’ subject, whereas the activity of the ‘low-pay’ subject showed the opposite pattern. These results provide direct evidence for the validity of this class of models, and also show that the brain’s reward circuitry is sensitive to both advantageous and disadvantageous inequality.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Effect of inequality manipulation on behaviour.
Figure 2: Effect of inequality manipulation on activity in the ventral striatum.
Figure 3: Effect of inequality manipulation on activity in the vmPFC.

References

  1. Fehr, E. & Schmidt, K. A theory of fairness, competition, and cooperation. Q. J. Econ. 114, 817–868 (1999)

    Article  Google Scholar 

  2. Adams, J. in Advances in Experimental Social Psychology (ed. Berkowitz, L.) 267–299 (Academic, 1965)

    Book  Google Scholar 

  3. Bolton, D. & Ockenfels, A. ERC: A theory of equity, reciprocity, and competition. Am. Econ. Rev. 82, 166–193 (2000)

    Article  Google Scholar 

  4. Dawes, C. T., Fowler, J. H., Johnson, T., McElreath, R. & Smirnov, O. Egalitarian motives in humans. Nature 446, 794–796 (2007)

    ADS  CAS  Article  Google Scholar 

  5. Loewenstein, G. F., Thompson, L. & Baserman, M. H. Social utility and decision making in interpersonal contexts. J. Pers. Soc. Psychol. 57, 426–441 (1989)

    Article  Google Scholar 

  6. Henrich, J. et al. ‘Economic man’ in cross-cultural perspective: behavioral experiments in 15 small-scale societies. Behav. Brain Sci. 28, 795–815 (2005)

    Article  Google Scholar 

  7. Andreoni, J. & Bernheim, B. Social image and the 50–50 norm: a theoretical and experimental analysis of audience effects. Econometrica 77, 1607–1636 (2009)

    MathSciNet  Article  Google Scholar 

  8. Falk, A., Fehr, E. & Fischbacher, U. Testing theories of fairness—intentions matter. Games Econ. Behav. 62, 287–303 (2008)

    MathSciNet  Article  Google Scholar 

  9. Rabin, M. Incorporating fairness into game theory and economics. Am. Econ. Rev. 83, 1281–1302 (1993)

    Google Scholar 

  10. Schultz, W., Dayan, P. & Montague, P. R. A neural substrate of prediction and reward. Science 275, 1593–1599 (1997)

    CAS  Article  Google Scholar 

  11. O’Doherty, J. P. Reward representations and reward-related learning in the human brain: insights from neuroimaging. Curr. Opin. Neurobiol. 14, 769–776 (2004)

    Article  Google Scholar 

  12. Fliessbach, K. et al. Social comparison affects reward-related brain activity in the human ventral striatum. Science 318, 1305–1308 (2007)

    ADS  CAS  Article  Google Scholar 

  13. Harbaugh, W. T., Mayr, U. & Burghart, D. R. Neural responses to taxation and voluntary giving reveal motives for charitable donations. Science 316, 1622–1625 (2007)

    ADS  CAS  Article  Google Scholar 

  14. Tabibnia, G., Satpute, A. B. & Lieberman, M. D. The sunny side of fairness: preference for fairness activates reward circuitry (and disregarding unfairness activates self-control circuitry). Psychol. Sci. 19, 339–347 (2008)

    Article  Google Scholar 

  15. Gurven, M. The evolution of contingent cooperation. Curr. Anthropol. 47, 185–192 (2006)

    Article  Google Scholar 

  16. Kakwani, N. C. Measurement of tax progressivity: an international comparison. Econ. J. 87, 71–80 (1977)

    MathSciNet  Article  Google Scholar 

  17. Frank, R. H. Are workers paid their marginal products. Am. Econ. Rev. 74, 549–571 (1984)

    Google Scholar 

  18. Akerlof, G. A. & Yellen, J. L. The fair wage-effort hypothesis and unemployment. Q. J. Econ. 105, 255–283 (1990)

    Article  Google Scholar 

  19. Krueger, A. B. & Mas, A. Strikes, scabs, and tread separations: labor strife and the production of defective Bridgestone/Firestone tires. J. Polit. Econ. 112, 253–289 (2004)

    Article  Google Scholar 

  20. Fehr, E. & Fischbacher, U. The nature of human altruism. Nature 425, 785–791 (2003)

    ADS  CAS  Article  Google Scholar 

  21. Fehr, E. & Gachter, S. Altruistic punishment in humans. Nature 415, 137–140 (2002)

    ADS  CAS  Article  Google Scholar 

  22. Sanfey, A. G., Rilling, J. K., Aronson, J. A., Nystrom, L. E. & Cohen, J. D. The neural basis of economic decision-making in the Ultimatum Game. Science 300, 1755–1758 (2003)

    ADS  CAS  Article  Google Scholar 

  23. Frank, R. H. Choosing the Right Pond: Human Behavior and the Quest for Status (Oxford Univ. Press, 1985)

    Google Scholar 

  24. Herrmann, B., Thoni, C. & Gachter, S. Antisocial punishment across societies. Science 319, 1362–1367 (2008)

    ADS  CAS  Article  Google Scholar 

  25. Hare, T. A., O’Doherty, J., Camerer, C. F., Schultz, W. & Rangel, A. Dissociating the role of the orbitofrontal cortex and the striatum in the computation of goal values and prediction errors. J. Neurosci. 28, 5623–5630 (2008)

    CAS  Article  Google Scholar 

  26. Plassmann, H., O’Doherty, J. & Rangel, A. Orbitofrontal cortex encodes willingness to pay in everyday economic transactions. J. Neurosci. 27, 9984–9988 (2007)

    CAS  Article  Google Scholar 

  27. Rilling, J. et al. A neural basis for social cooperation. Neuron 35, 395–405 (2002)

    CAS  Article  Google Scholar 

  28. Moll, J. et al. Human fronto-mesolimbic networks guide decisions about charitable donation. Proc. Natl Acad. Sci. USA 103, 15623–15628 (2006)

    ADS  CAS  Article  Google Scholar 

  29. Singer, T. et al. Empathic neural responses are modulated by the perceived fairness of others. Nature 439, 466–469 (2006)

    ADS  CAS  Article  Google Scholar 

  30. Krajbich, I., Adolphs, R., Tranel, D., Denburg, N. L. & Camerer, C. F. Economic games quantify diminished sense of guilt in patients with damage to the prefrontal cortex. J. Neurosci. 29, 2188–2192 (2009)

    CAS  Article  Google Scholar 

  31. Andreoni, J. & Vesterlund, L. Which is the fair sex? Gender differences in altruism. Q. J. Econ. 116, 293–312 (2001)

    Article  Google Scholar 

  32. Costa, P. T. & McCrae, R. R. Revised NEO Personality Inventory (NEO PI-R) and NEO Five-Factor Inventory (NEO-FFI) Professional Manual (Psychological Assessment Resources, Inc., 1992)

    Google Scholar 

  33. Deichmann, R., Gottfried, J. A., Hutton, C. & Turner, R. Optimized EPI for fMRI studies of the orbitofrontal cortex. Neuroimage 19, 430–441 (2003)

    CAS  Article  Google Scholar 

  34. de Quervain, D. J. et al. The neural basis of altruistic punishment. Science 305, 1254–1258 (2004)

    ADS  CAS  Article  Google Scholar 

  35. Nieuwenhuis, S. et al. Activity in human reward-sensitive brain areas is strongly context dependent. Neuroimage 25, 1302–1309 (2005)

    Article  Google Scholar 

  36. Breiter, H. C., Aharon, I., Kahneman, D., Dale, A. & Shizgal, P. Functional imaging of neural responses to expectancy and experience of monetary gains and losses. Neuron 30, 619–639 (2001)

    CAS  Article  Google Scholar 

  37. O’Doherty, J., Critchley, H., Deichmann, R. & Dolan, R. J. Dissociating valence of outcome from behavioral control in human orbital and ventral prefrontal cortices. J. Neurosci. 23, 7931–7939 (2003)

    Article  Google Scholar 

  38. Lohrenz, T., McCabe, K., Camerer, C. F. & Montague, P. R. Neural signature of fictive learning signals in a sequential investment task. Proc. Natl Acad. Sci. USA 104, 9493–9498 (2007)

    ADS  CAS  Article  Google Scholar 

  39. Stephan, K. E., Penny, W. D., Daunizeau, J., Moran, R. J. & Friston, K. J. Bayesian model selection for group studies. Neuroimage 46, 1004–1017 (2009)

    Article  Google Scholar 

Download references

Acknowledgements

We thank B. Bushong, N. Tetrault, S. Bray, J. Gläscher and R. Lee for their assistance. This work was supported by grants from the US National Science Foundation to J.O.D. (0617174), from the Human Frontiers of Science Program to C.F.C., and from the Gordon and Betty Moore Foundation to J.O.D., A.R., C.F.C. and the Caltech Brain Imaging Center.

Author Contributions E.T., A.R., C.F.C. and J.O.D. designed the experiment, E.T. conducted the experiment and analysed the data, and E.T., A.R., C.F.C. and J.O.D. discussed the results and wrote the paper.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to John P. O’Doherty.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Figure 1 and Legend and Supplementary Tables 1-2. (PDF 81 kb)

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Tricomi, E., Rangel, A., Camerer, C. et al. Neural evidence for inequality-averse social preferences. Nature 463, 1089–1091 (2010). https://doi.org/10.1038/nature08785

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature08785

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing