A Meta‐Analysis of Functional Magnetic Resonance Imaging Studies on In‐Group and Out‐Group Categorization

INTRODUCTION: Systematic variations in neural activation patterns during processing of group categorization is a facet often overlooked in extant meta-analyses that typically treated all group memberships and task types as homogenous entities. Recognizing the necessity to differentiate between various group memberships and task types due to them eliciting distinct neural activity, our study addressed this gap by conducting a more fine-grained exploration. METHODS: A comprehensive meta-analytic approach using the activation likelihood estimation (ALE) following PRISMA guidelines was employed. Inclusion criteria were task-fMRI studies, whole-brain analyses in a standard stereotaxic space, involved healthy adults, and published in English. Meta-analyses were performed using GingerALE. RESULTS: ) located in the right postcentral gyrus, and right posterior cingulate gyrus. CONCLUSION: Our unrestricted search approach with ALE methodology extends beyond previous categorically constrained meta-analyses by capturing group dynamics not limited to predefined categories. The distinct activation patterns for ethnicity-based categorization and empathy processing tasks indicate multiple neural pathways rather than universal mechanisms for group processing. These context-dependent patterns suggest interventions must target specific group-task combinations rather than assume uniform neural processes.