What is illusory correlation in simple terms?

Mistakenly believing two things are related because of conspicuous cases, when they are actually unrelated or only weakly related.

How is it related to stereotypes?

Rare groups and rare bad behaviors stick together in memory, so negative stereotypes of minority groups can form even without real differences.

Illusory Correlation

🧠 Psychology By CampusDown Wiki Editorial Team Last updated October 27, 2026

Illusory correlation is the perception of a relationship between two events or traits that are in fact unrelated or only weakly related. Loren Chapman named it in 1967. There is a distinctiveness-based type, in which rare and conspicuous things that co-occur are remembered better and mistaken for a relationship, and an expectancy-based type, in which people remember cases that fit prior expectations and overestimate the relationship. It is described as one route by which negative stereotypes of minority groups form.

Contents

1. Concept and origins
2. Distinctiveness-based illusory correlation
3. Expectancy-based type and explanations
4. FAQ
5. References

Concept and origins

In experiments presenting word pairs, Chapman (1967) found that people reported that semantically related or conspicuous pairs had appeared more often, even though all pairs appeared equally often, and called this illusory correlation. Chapman and Chapman (1967) showed that clinical psychologists consistently saw relationships in drawing tests, such as "drawing large eyes indicates suspiciousness," that were absent from the actual data. These relationships came not from the data but from people's prior expectations and common sense. Illusory correlation thus appears even in expert judgment.

Distinctiveness-based illusory correlation

Hamilton and Gifford (1976) showed participants behaviors by members of a majority group A and a minority group B. Both groups had the same ratio of desirable to undesirable behaviors, but the minority group and the rarer undesirable behaviors were both distinctive because infrequent. Participants remembered minority group B as having performed more undesirable behaviors and evaluated it more negatively. Mullen and Johnson's (1990) meta-analysis confirmed that the effect is reliable. The result shows that negative stereotypes of minority groups can arise from information processing alone, without real differences or prejudice.

Expectancy-based type and explanations

Hamilton and Rose (1980) showed expectancy-based illusory correlation: people better remember cases that fit existing stereotypes and see a stronger relationship than the data contain. This helps explain why stereotypes persist even in the face of contrary evidence. There are several explanations for the distinctiveness-based effect. Fiedler (1991) proposed that because there is less information about the minority group, information loss in memory produces differences in ratios, and Sherman and colleagues (2009) proposed an attentional model in which people learn the common features of the majority first and then attend to the distinguishing features of the minority. Illusory correlation is treated, along with the outgroup homogeneity effect, as a cognitive foundation of stereotype formation.

FAQ

What is illusory correlation in simple terms?: Mistakenly believing two things are related because of conspicuous cases, when they are actually unrelated or only weakly related.
How is it related to stereotypes?: Rare groups and rare bad behaviors stick together in memory, so negative stereotypes of minority groups can form even without real differences.

Sources reviewed: 2026-10-26

References

Chapman, L. J. (1967). Illusory correlation in observational report. Journal of Verbal Learning and Verbal Behavior, 6(1), 151–155. The paper that coined illusory correlation.
Chapman, L. J., & Chapman, J. P. (1967). Genesis of popular but erroneous psychodiagnostic observations. Journal of Abnormal Psychology, 72(3), 193–204. Clinicians see expectancy-based illusory correlations.
Hamilton, D. L., & Gifford, R. K. (1976). Illusory correlation in interpersonal perception: A cognitive basis of stereotypic judgments. Journal of Experimental Social Psychology, 12(4), 392–407. The classic distinctiveness-based illusory correlation study.
Hamilton, D. L., & Rose, T. L. (1980). Illusory correlation and the maintenance of stereotypic beliefs. Journal of Personality and Social Psychology, 39(5), 832–845. Expectancy-based illusory correlation maintains stereotypes.
Mullen, B., & Johnson, C. (1990). Distinctiveness-based illusory correlations and stereotyping: A meta-analytic integration. British Journal of Social Psychology, 29(1), 11–28. A meta-analysis of distinctiveness-based illusory correlation.
Fiedler, K. (1991). The tricky nature of skewed frequency tables: An information loss account of distinctiveness-based illusory correlations. Journal of Personality and Social Psychology, 60(1), 24–36. An information-loss account of the effect.
Sherman, J. W., Kruschke, J. K., Sherman, S. J., Percy, E. J., Petrocelli, J. V., & Conrey, F. R. (2009). Attentional processes in stereotype formation: A common model for category accentuation and illusory correlation. Journal of Personality and Social Psychology, 96(2), 305–323. An attentional model of illusory correlation.

Reports and materials that use this theory (Korean)

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Outgroup Homogeneity EffectWhat the outgroup homogeneity effect is: perceiving ingroup members as diverse but outgroup members as all alike. Covers classic experiments, familiarity and categorization explanations, exceptions and meta-analytic evidence.🧠 Psychology Stereotype Content ModelWhat the stereotype content model is: people judge groups on warmth and competence, and the combinations produce pity, envy, contempt or admiration. Covers origins, the BIAS map, cross-cultural tests and critiques.🧠 Psychology EntitativityWhat entitativity is: the degree to which a collection of people is perceived as a unified entity, a real group. Covers its cues, types of groups and its effects on stereotyping, threat and identification.🧠 Psychology Linguistic Intergroup BiasWhat linguistic intergroup bias is: describing ingroup good and outgroup bad behavior abstractly, and ingroup bad and outgroup good behavior concretely. Covers research, mechanisms and how language transmits stereotypes.🧠 Psychology

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This article was last updated on October 27, 2026. It is based on widely recognized original works and textbooks; when citing it in a paper, please check the original sources listed in the references.