The horn effect, closely related to the halo effect, is a form of cognitive bias that causes one's perception of another to be unduly influenced by a single negative trait.[1][2][3] An example of the horn effect may be that an observer is more likely to assume a physically unattractive person is morally inferior to an attractive person, despite the lack of relationship between morality and physical appearance.[4][5]


The term is derived from the word "horn" and refers to the devil's horns. This is in contrast to the word halo and the halo effect, based on the concept of a saint's halo.[6]

In a 1920 study published by Thorndike[7] that focused on the halo effect, it was noted that "ratings were apparently affected by a marked tendency to think of the person in general as rather good or rather interior [sic][a] and to color the judgments of the qualities by this general feeling".[b]

Alternate terminology

It is sometimes called the horns effect,[2] reverse-halo effect, or devil effect.[8]

Bias in action

The horn effect occurs when "individuals believe that negative traits are connected to each other."[3] It is a phenomenon in which an observer's judgment of a person is adversely affected by the presence of (for the observer) an unfavorable aspect of this person.

See also

Explanatory notes

  1. ^ "inferior"
  2. ^ Although not popularizing the actual term Horn effect.


  1. ^ "Halo Effect: Definition and Examples". Simply Psychology. Retrieved 2022-02-11.
  2. ^ a b Belludi, Nagesh (30 April 2013). "The Halo and Horns Effects [Rating Errors]". Right Attitudes. Retrieved 15 August 2017.
  3. ^ a b Kennon, Joshua (12 November 2011). "Mental Model: Horns Effect and Halo Effect". Retrieved 15 August 2017.
  4. ^ Long-Crowell, Erin. "The Halo Effect: Definition, Advantages & Disadvantages". Psychology 104: Social Psychology. Retrieved September 30, 2015.
  5. ^ Nisbett, Richard E; Wilson, Timothy D (1977). "The halo effect: Evidence for unconscious alteration of judgments" (PDF). Journal of Personality and Social Psychology. American Psychological Association. 35 (4): 250–56. doi:10.1037/0022-3514.35.4.250. hdl:2027.42/92158. S2CID 17867385.
  6. ^ "halo | History, Art, & Facts". Encyclopedia Britannica. Retrieved 2019-02-03.
  7. ^ Thorndike, EL (1920), "A constant error in psychological ratings", Journal of Applied Psychology, 4 (1): 25–29, doi:10.1037/h0071663
  8. ^ "Halo Effect: Definition and Examples | Simply Psychology". Retrieved 2022-02-11.
  9. ^ Glennie, Jonathan (3 May 2011). "Hugo Chávez's reverse-halo effect". The Guardian.
  10. ^ Ostrove, Nancy; Sigall, Harold (1975). "Beautiful but Dangerous: Effects of Offender Attractiveness and Nature of the Crime on Juridic Judgment". Journal of Personality and Social Psychology. 31 (3): 410–14. doi:10.1037/h0076472.