RESUMEN
Negative attitudes and stigmatization toward sexual minorities is a cause of minority stress of non-heterosexual persons on an individual level and has a negative impact on democratic coexistence in postmodern, plural society on a societal level. Derived from clinical research, we developed a short metacognitive training (MCT) intended to induce doubt toward inaccurate beliefs about LGBTIQ+ persons. We expected this MCT to reduce homonegativity, threat perceptions of LGBTIQ+ persons, and to foster extended outgroup tolerance compared to an education and a no-treatment control condition. We tested this hypothesis in U.S. Republican leaners who represent a social group that is likely to hold homonegative attitudes. We randomly assigned 490 U.S. Republican leaners to an MCT condition comprising 16 questions and respective answers (n = 166) vs. an education control condition (n = 164) vs. a no-treatment control condition (n = 160). We found that Republican leaners after receiving MCT (1) had a significant reduction of homonegativity (ds ≥ 0.28), (2) significantly perceived LGBTIQ+ persons as less threatening (ds ≥ 0.30), and (3) were significantly more tolerant of various outgroups such as LGBTIQ+ persons, feminists, liberals, and climate activists (ds ≥ 0.23) relative to both control conditions. The small effects of this short intervention and the possibility of systematically applying MCT in social discourse to reduce homonegativity with its potential significance for LGBTIQ+ individuals' mental health are discussed. Furthermore, we highlight this pilot study's significance toward intervention possibilities regarding political division and polarization in postmodern, democratic societies.