What is the halo effect?
The halo effect is the tendency for one prominent good trait to spill over into judgments of unrelated traits, much like the glowing halo in religious art lights up the whole figure. The reverse, where one flaw drags down everything else, is the horn effect.
- Named by
- Edward Thorndike (1920)
- Core idea
- An impression of one trait spreads to others
- Opposite
- Horn (or devil) effect
- Related
- Primacy effect, confirmation bias, rater error
Thorndike’s discovery
Thorndike asked military commanders to rate officers on intelligence, leadership, physique, loyalty and other qualities. The ratings were suspiciously correlated: officers judged handsome and fit also got high marks for intelligence and leadership. He called it "a constant error" in psychological ratings.
Key studies
| Study | Design | Finding |
|---|---|---|
| Dion et al. (1972) | Judging people from photos | Attractive people were expected to be kinder and more successful |
| Landy and Sigall (1974) | Same essay, different author photo | Essays with an attractive author photo were graded higher |
| Nisbett and Wilson (1977) | Same lecturer acting warm or cold | The warm version’s appearance and accent were rated more favorably, and viewers denied being influenced |
Nisbett and Wilson’s study shows the uncomfortable part: people usually cannot see the halo working on themselves.
Everyday examples
- Hiring: a candidate from a top university or with a polished manner may be assumed competent at everything. Many employers now use structured interviews and anonymized applications to counter this.
- Grading: a well-liked student’s work can receive more generous marks; rubrics and anonymous marking help.
- Marketing: celebrity endorsements and brand extensions, such as trusting a new product because the company’s phone is great, rely on halo effects.
- Business analysis: Rosenzweig (2007) argued that when a company performs well, observers praise its culture, leadership and strategy, then criticize the same traits when results decline.
Courtrooms are not immune. Research on juror judgments suggests that appearance and demeanor can affect perceived credibility, which is why procedures that tie decisions to evidence matter.
How to reduce the halo effect
- Rate one criterion at a time across all candidates instead of rating one person on everything.
- Use structured interviews with the same questions and scoring anchors for everyone.
- Write down evidence for each score in behavioral terms.
- Collect ratings from several evaluators independently before discussing.
See also first impressions and the primacy effect and the anchoring effect.
Frequently asked questions
- What is an example of the halo effect?
- Assuming an attractive person is also smart and kind, rating a graduate of a famous university as more capable, or trusting a product because a liked celebrity endorses it.
- How is the halo effect different from the primacy effect?
- The halo effect spreads one trait to other traits; the primacy effect gives information encountered first more weight than later information.
- What is the horn effect?
- The opposite of the halo effect: one negative trait leads to lower ratings of a person’s other qualities.
References
- Thorndike, E. L. (1920). A constant error in psychological ratings. Journal of Applied Psychology, 4(1), 25–29.
- Dion, K., Berscheid, E., & Walster, E. (1972). What is beautiful is good. Journal of Personality and Social Psychology, 24(3), 285–290.
- Nisbett, R. E., & Wilson, T. D. (1977). The halo effect: Evidence for unconscious alteration of judgments. Journal of Personality and Social Psychology, 35(4), 250–256.
- Landy, D., & Sigall, H. (1974). Beauty is talent: Task evaluation as a function of the performer’s physical attractiveness. Journal of Personality and Social Psychology, 29(3), 299–304.
- Rosenzweig, P. (2007). The halo effect: … and the eight other business delusions that deceive managers. New York: Free Press.