The dual neural burden of code-switching: Executive depletion and disrupted synchrony in cross-group social interactions

Code-switching, the strategic adjustment of behavior and expression to align with dominant cultural norms, is a pervasive experience for racial and ethnic minorities, consistently linked to psychological fatigue and inauthenticity in self-report studies. Yet its neurocognitive mechanisms and impact on real-time social interaction remain unknown. Using dual-fMRI hyperscanning, the researcher monitored brain activity in cross-group dyads (N = 20 individuals, 10 dyads) during cooperative and rapport-building tasks. The cognitive demand for code-switching in minority-group participants was experimentally manipulated via identity priming, inducing either Congruent (personal identity) or Incongruent (assimilationist) mindsets. In the Incongruent condition, minority participants showed heightened activation in the fronto-parietal control network (FPCN) and dorsal anterior cingulate cortex (dACC), indicating increased cognitive effort, alongside suppressed activity in the Default Mode Network (DMN). This internal state was associated with significantly reduced inter-brain synchrony between dyads within the FPCN and temporo-parietal junction (TPJ). Behaviorally, Incongruent-condition interactions were rated lower in rapport, an effect fully mediated by increased FPCN activity in minority participants. These findings reveal a dual neural pathway for code-switching costs: executive resource depletion at the individual level and impaired neural alignment necessary for fluent social connection, providing a mechanistic brain-based account of this critical social phenomenon.