Executive control- and reward-related neural processes associated with the opportunity to engage in voluntary dishonest moral decision making.

Research has begun to examine the neurocognitive processes underlying voluntary moral decision making, which involves engaging in honest or dishonest behavior in a setting in which the individual is free to make his or her own moral decisions. Employing event-related potentials, we measured executive control-related and reward-related neural processes during an incentivized coin-guessing task in which participants had the opportunity to voluntarily engage in dishonest behavior, by overreporting their wins to maximize earnings. We report four primary findings: First, the opportunity to deceive recruited executive control processes involving conflict monitoring and conflict resolution, as evidenced by a higher N2 and a smaller P3. Second, processing the outcome of the coin flips engaged reward-related processes, as evidenced by a larger medial feedback negativity (MFN) for incorrect (loss) than for correct (win) guesses, reflecting a reward prediction error signal. Third, elevated executive control-related neural activity reflecting conflict resolution (i.e., an attenuated executive control P3) predicted a greater likelihood of engaging in overall deceptive behavior. Finally, whereas elevated reward-related neural activity (the reward P3) was associated with a greater likelihood of engaging in overall deceptive behavior, an elevated reward prediction error signal (MFN difference score) predicted increased trial-by-trial moral behavioral adjustment (i.e., a greater likelihood to overreport wins following a previous honest loss than following a previous honest win trial). Collectively, these findings suggest that both executive control- and reward-related neural processes are implicated in moral decision making.