[2][3] Hamilton & Rose (1980) found that stereotypes can lead people to expect certain groups and traits to fit together, and then to overestimate the frequency with which these correlations actually occur.
"Illusory correlation" was originally coined by Chapman (1967) to describe people's tendencies to overestimate relationships between two groups when distinctive and unusual information is presented.
[5][6] The concept was used to question claims about objective knowledge in clinical psychology through Chapmans' refutation of many clinicians' widely used Wheeler signs for homosexuality in Rorschach tests.
[7] David Hamilton and Robert Gifford (1976) conducted a series of experiments that demonstrated how stereotypic beliefs regarding minorities could derive from illusory correlation processes.
[8] A parallel effect occurs when people judge whether two events, such as pain and bad weather, are correlated.
[9][10] Most explanations for illusory correlation involve psychological heuristics: information processing short-cuts that underlie many human judgments.
[11] Martin Hilbert (2012) proposes an information processing mechanism that assumes a noisy conversion of objective observations into subjective judgments.
In an experimental study done by Eder, Fiedler and Hamm-Eder (2011), the effects of working-memory capacity on illusory correlations were investigated.
[16] Johnson and Jacobs (2003) performed an experiment to see how early in life individuals begin forming illusory correlations.
Children in grades 2 and 5 were exposed to a typical illusory correlation paradigm to see if negative attributes were associated with the minority group.
[18] Two studies performed by Ratliff and Nosek examined whether or not explicit and implicit attitudes affected illusory correlations.