One too many categories: an experimental test on the effectiveness of a dual-identity recategorization intervention on age-based bias

A laboratory experiment was conducted on a convenient sample of N?=?724 introductory Psychology students from the southeastern United States, to test the effectiveness of a dual identity recategorization intervention when applied on age bias toward a hypothetical older adult, when applied on individuals both low and high on the spectrum of ageism, and when applied on members of the naturally occurring in-group, younger adults. As predicted by Optimal Distinctiveness Theory, the intervention served to worsen evaluations of an in-group target vis-à-vis a control group that was not exposed to the intervention, and especially when applied on individuals possessing lower amounts of the in-group bias in question, ageism. Moreover, although age-based stereotyping and in-group bias against an older applicant was demonstrated, the intervention was found to have no effect in changing evaluations of an older target relative to the control group. Results and implications for future research are discussed.