Does mindfulness improve intergroup bias, internalized bias, and anti-bias outcomes? A meta-analysis of the evidence and agenda for future research

This study integrates the conceptual and empirical research on mindfulness and intergroup bias to guide a meta-analysis that examines associations between mindfulness and (a) different manifestations of bias, e.g., implicit and explicit attitudes, affect, and behavior, directed towards (b) different bias targets, e.g., outgroup or ingroup (internalized bias), by (c) intergroup orientation, e.g., towards bias or anti-bias. Of 70 independent samples, 42 (178 effect sizes; N = 3,229) were studies of mindfulness-based interventions (MBIs) and 30 (150 effect sizes; N = 6,002) were correlational studies. Unconditional mixed-effects structural equation models showed a large, negative effect of mindfulness on bias for intervention (d = -0.56, CI 95% [-0.72, -0.40]) and correlational (r = -0.17 [-0.27, -0.03]) studies. Effects were comparable for intergroup bias and internalized bias; the largest effects were for behavioral outcomes. We conclude by identifying gaps in the evidence base and outline an agenda for future research.