Objectives Recent meta-analyses suggest that mindfulness meditation may enhance prosocial behavior, while evidence regarding moral behavior is still scarce. We combined a randomized controlled mindfulness training design with an ecologically valid moral decision-making task (Temptation to Lie Card Game; TLCG), in which participants were tempted to deceive an opponent to increase their monetary payoff.

Method TLCG and self-report measures (in the domains of attention regulation, body awareness, emotion regulation, and change in the perspective of the self) were administered to participants who underwent the mindfulness meditation training (experimental group, n = 44) or were waitlisted (control group, n = 25) twice: before and after the 8-week training.

Results Concerning moral decision-making, we observed a significant effect involving condition, time, and group. Trained participants deceived significantly less in the post-training as compared with the pre-training phase (p = 0.03), while untrained ones showed no significant change (p = 0.58). In the self-reports, significant effects involving time and group were found for the Multidimensional Assessment of Interoceptive Awareness (MAIA-2) in Self-Regulation, Attention Regulation, Body Listening, and for the Five Facet Mindfulness Questionnaire (FFMQ) in Non-Reactivity to inner experience. Trained participants showed a time-related increase in all subscales scores, while untrained ones did not. Finally, a moderation analysis revealed a significant interaction between weekly mindfulness meditation training minutes and MAIA-2 Attention Regulation (post-training) on moral behavior change.

Conclusions Our preliminary results suggest that mindfulness meditation practice decreases self-serving dishonest behavior and increases awareness of one’s bodily and emotional state. In particular, the amount of mindfulness meditation practice predicted moral behavior change in practitioners who reported the highest regulation of attention towards internal bodily signals.