Brief Mindfulness Intervention Improved Self-Reported Acceptance but Not Neural or Behavioral Reactivity to Errors

Acceptance, nonjudgmental awareness of the present-moment experiences, is a central component of mindfulness. This study used a pretest-posttest design to examine whether a brief mindfulness intervention (MI) could increase self-reported acceptance and reduce affective reactivity to errors, as indexed by error-related negativity (ERN), error positivity (Pe), and post-error slowing (PES). Meditation-naïve participants (n = 121, ages 18-31 years, 69% female) were randomly assigned to either a mindfulness group, which engaged in 10 min of guided mindful breathing, or a control group, which listened to a Ted talk on green living. Both groups completed a Flanker task before and after the intervention to elicit errors under time pressure. Results showed that participants in the mindfulness group reported greater acceptance following the intervention; however, no corresponding changes were observed in ERN or PES. Instead, both groups showed practice effects, with faster reaction times and larger Pe amplitudes reflecting increased response certainty. These findings suggest that while a brief MI may enhance subjective acceptance, it may not be sufficient to alter neural or behavioral markers of affective error reactivity. Longer or more intensive mindfulness training may be required to influence these deeper cognitive and emotional processes.