Changing people’s views of outgroups through individual-to-group generalisation: meta-analytic reviews and theoretical considerations

ABSTRACT Through individual-to-group generalisation, information about individual members of stigmatised social groups changes the outgroup judgment. This article reports meta-analytic reviews of over 30 years of experimental, lab-based research on individual-to-group generalisation (107 independent tests; 5393 participants). In a first meta-analysis, a positive, medium-size generalisation effect was detected (r = .28, p < .001), reflecting significant generalisation of outgroup exemplar information to the outgroup judgment. This effect was moderated by the number of exemplars and exemplar typicality, with more moderately atypical exemplars maximising generalisation effects. Several other design parameters—including type of control condition, generalisation measures, mode of information provision, type of target outgroup and origin of study—did not moderate the positive generalisation effect. A second meta-analysis investigated the interplay between metacognitions and generalisation and found assimilation effects with metacognitive triggers encouraging exemplar inclusion, and contrast effects with metacognitive cues encouraging exemplar exclusion. These results demonstrate that the same outgroup exemplar can lead to bias reduction or bias exacerbation, depending on available meta-cognitive cues. Findings are discussed in terms of implications for intergroup psychology, generalisation theory and bias reduction interventions.