Beliefs about bad people are volatile


People form moral impressions rapidly, effortlessly and from a remarkably young age1,2,3,4,5. Putatively ‘bad’ agents command more attention and are identified more quickly and accurately than benign or friendly agents5,6,7,8,9,10,11,12. Such vigilance is adaptive, but can also be costly in environments where people sometimes make mistakes, because incorrectly attributing bad character to good people damages existing relationships and discourages forming new relationships13,14,15,16. The ability to accurately infer the moral character of others is critical for healthy social functioning, but the computational processes that support this ability are not well understood. Here, we show that moral inference is explained by an asymmetric Bayesian updating mechanism in which beliefs about the morality of bad agents are more uncertain (and therefore more volatile) than beliefs about the morality of good agents. This asymmetry seems to be a property of learning about immoral agents in general, as we also find greater uncertainty for beliefs about the non-moral traits of bad agents. Our model and data reveal a cognitive mechanism that permits flexible updating of beliefs about potentially threatening others, a mechanism that could facilitate forgiveness when initial bad impressions turn out to be inaccurate. Our findings suggest that negative moral impressions destabilize beliefs about others, promoting cognitive flexibility in the service of cooperative but cautious behaviour.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Learning task and model.
Fig. 2: Asymmetry in moral impression formation, study 2.
Fig. 3: Forming impressions of morality versus competence, study 3.
Fig. 4: Inferences about moral character affect learning about non-moral traits and impression updating.

Data availability

The data that support the findings of this study are available from the corresponding author upon request.


  1. 1.

    Fiske, S. T., Cuddy, A. J. C. & Glick, P. Universal dimensions of social cognition: warmth and competence. Trends Cogn. Sci. 11, 77–83 (2007).

  2. 2.

    Uleman, J. S. & Kressel, L. M. in Oxford Handbook of Social Cognition (ed. Calston, D. E.) 53–73 (Oxford Univ. Press, Oxford, 2013).

  3. 3.

    Todorov, A., Pakrashi, M. & Oosterhof, N. N. Evaluating faces on trustworthiness after minimal time exposure. Soc. Cogn. 27, 813–833 (2009).

  4. 4.

    Engell, A. D., Haxby, J. V. & Todorov, A. Implicit trustworthiness decisions: automatic coding of face properties in the human amygdala. J. Cogn. Neurosci. 19, 1508–1519 (2007).

  5. 5.

    Kiley Hamlin, J., Wynn, K. & Bloom, P. Three-month-olds show a negativity bias in their social evaluations. Dev. Sci. 13, 923–929 (2010).

  6. 6.

    Schupp, H. T. et al. The facilitated processing of threatening faces: an ERP analysis. Emotion 4, 189–200 (2004).

  7. 7.

    Öhman, A., Lundqvist, D. & Esteves, F. The face in the crowd revisited: a threat advantage with schematic stimuli. J. Pers. Soc. Psychol. 80, 381–396 (2001).

  8. 8.

    Vanneste, S., Verplaetse, J., Hiel, A. V. & Braeckman, J. Attention bias toward noncooperative people. A dot probe classification study in cheating detection. Evol. Hum. Behav. 28, 272–276 (2007).

  9. 9.

    Skowronski, J. J. & Carlston, D. E. Negativity and extremity biases in impression formation: a review of explanations. Psychol. Bull. 105, 131–142 (1989).

  10. 10.

    Fiske, S. T. Attention and weight in person perception: the impact of negative and extreme behavior. J. Pers. Soc. Psychol. 38, 889–906 (1980).

  11. 11.

    Pratto, F. & John, O. P. Automatic vigilance: the attention-grabbing power of approach- and avoidance-related social information. J. Pers. Soc. Psychol. 61, 380–391 (1991).

  12. 12.

    Baumeister, R. F., Bratslavsky, E., Finkenauer, C. & Vohs, K. D. Bad is stronger than good. Rev. Gen. Psychol. 5, 323–370 (2001).

  13. 13.

    McCullough, M. E. Beyond Revenge: The Evolution of the Forgiveness Instinct (John Wiley & Sons, San Francisco, CA, 2008).

  14. 14.

    Axelrod, R. M. The Evolution of Cooperation (Basic Books, New York, NY, 2006).

  15. 15.

    Molander, P. The optimal level of generosity in a selfish, uncertain environment. J. Conflict Resolut. 29, 611–618 (1985).

  16. 16.

    Johnson, D. D. P., Blumstein, D. T., Fowler, J. H. & Haselton, M. G. The evolution of error: error management, cognitive constraints, and adaptive decision-making biases. Trends Ecol. Evol. 28, 474–481 (2013).

  17. 17.

    Cosmides, L. & Tooby, J. in The Adapted Mind: Evolutionary Psychology and the Generation of Culture (eds Barkow, J. H. et al.) 163–228 (Oxford Univ. Press, Oxford, 1992).

  18. 18.

    Nowak, M. A. & Sigmund, K. Tit for tat in heterogeneous populations. Nature 355, 250–253 (1992).

  19. 19.

    Wu, J. & Axelrod, R. How to cope with noise in the iterated prisoner’s dilemma. J. Conflict Resolut. 39, 183–189 (1995).

  20. 20.

    Fudenberg, D., Rand, D. G. & Dreber, A. Slow to anger and fast to forgive: cooperation in an uncertain world. Am. Econ. Rev. 102, 720–749 (2012).

  21. 21.

    Mathys, C., Daunizeau, J., Friston, K. J. & Stephan, K. E. A Bayesian foundation for individual learning under uncertainty. Front. Hum. Neurosci. 5, 39 (2011).

  22. 22.

    Ohman, A. Face the beast and fear the face: animal and social fears as prototypes for evolutionary analyses of emotion. Psychophysiology 23, 123–145 (1986).

  23. 23.

    Nassar, M. R. et al. Rational regulation of learning dynamics by pupil-linked arousal systems. Nat. Neurosci. 15, 1040–1046 (2012).

  24. 24.

    Reeder, G. D. & Coovert, M. D. Revising an impression of morality. Soc. Cogn. 4, 1–17 (1986).

  25. 25.

    Mende-Siedlecki, P., Baron, S. G. & Todorov, A. Diagnostic value underlies asymmetric updating of impressions in the morality and ability domains. J. Neurosci. 33, 19406–19415 (2013).

  26. 26.

    Crockett, M. J., Kurth-Nelson, Z., Siegel, J. Z., Dayan, P. & Dolan, R. J. Harm to others outweighs harm to self in moral decision making. Proc. Natl Acad. Sci. USA 111, 17320–17325 (2014).

  27. 27.

    Crockett, M. J., Siegel, J. Z., Kurth-Nelson, Z., Dayan, P. & Dolan, R. J. Moral transgressions corrupt neural representations of value. Nat. Neurosci. 20, 879–885 (2017).

  28. 28.

    Gert, B. Common Morality: Deciding What to Do (Oxford Univ. Press, Oxford, 2004).

  29. 29.

    Diaconescu, A. O. et al. Inferring on the intentions of others by hierarchical Bayesian learning. PLoS Comput. Biol. 10, e1003810 (2014).

  30. 30.

    Vossel, S. et al. Spatial attention, precision, and Bayesian inference: a study of saccadic response speed. Cereb. Cortex 24, 1436–1450 (2014).

  31. 31.

    Behrens, T. E. J., Hunt, L. T., Woolrich, M. W. & Rushworth, M. F. S. Associative learning of social value. Nature 456, 245–249 (2008).

  32. 32.

    Hackel, L. M., Doll, B. B. & Amodio, D. M. Instrumental learning of traits versus rewards: dissociable neural correlates and effects on choice. Nat. Neurosci. 18, 1233–1235 (2015).

  33. 33.

    Brañas-Garza, P., Rodríguez-Lara, I. & Sánchez, A. Humans expect generosity. Sci. Rep. 7, 42446 (2017).

  34. 34.

    Rand, D. G. Cooperation, fast and slow: meta-analytic evidence for a theory of social heuristics and self-interested deliberation. Psychol. Sci. 27, 1192–1206 (2016).

  35. 35.

    Rosenberg, S., Nelson, C. & Vivekananthan, P. S. A multidimensional approach to the structure of personality impressions. J. Pers. Soc. Psychol. 9, 283–294 (1968).

  36. 36.

    Robinson, O. J., Vytal, K., Cornwell, B. R. & Grillon, C. The impact of anxiety upon cognition: perspectives from human threat of shock studies. Front. Hum. Neurosci. 7, 203 (2013).

  37. 37.

    Judd, C. M., James-Hawkins, L., Yzerbyt, V. & Kashima, Y. Fundamental dimensions of social judgment: understanding the relations between judgments of competence and warmth. J. Pers. Soc. Psychol. 89, 899–913 (2005).

  38. 38.

    Tormala, Z. L. & Rucker, D. D. Attitude certainty: a review of past findings and emerging perspectives. Soc. Pers. Psychol. Compass 1, 469–492 (2007).

Download references


We thank D. Carlston, E. Boorman, C. Summerfield and T. Behrens for helpful feedback. We thank T. Tyurkina and L. Caviola for developing the web applications utilized in studies 2–7 for data collection. J.Z.S. was supported by a Clarendon and Wellcome Trust Society and Ethics award (104980/Z/14/Z). R.B.R. was supported by a MRC Career Development award (MR/N02401X/1). This work was supported by a Wellcome Trust ISSF award (204826/Z/16/Z), the John Fell Fund and the Academy of Medical Sciences (SBF001/1008). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.

Author information

M.J.C. and J.Z.S. conceived the studies. J.Z.S., C.M., R.B.R. and M.J.C. designed the studies. J.Z.S. collected the data. J.Z.S., C.M. and M.J.C. analysed the data. J.Z.S. and M.J.C. wrote the manuscript with edits from R.B.R. and C.M.

Correspondence to Molly J. Crockett.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Methods, Supplementary Results, Supplementary Tables 2–4, 6–12 and Supplementary Figures 1–7

Reporting Summary

Supplementary Table 1

Supplementary Table 5

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Siegel, J.Z., Mathys, C., Rutledge, R.B. et al. Beliefs about bad people are volatile. Nat Hum Behav 2, 750–756 (2018).

Download citation

Further reading