Abstract
As one of the commonly used folk psychological concepts, self-deception has been intensively discussed yet is short of solid ground from cognitive neuroscience. Self-deception is a biased cognitive process of information to obtain or maintain a false belief that could be both self-enhancing or self-diminishing. Study 1 (N = 152) captured self-deception by adopting a modified numerical discrimination task that provided cheating opportunities, quantifying errors in predicting future performance (via item-response theory model), and measuring the belief of how good they are at solving the task (i.e., self-efficacy belief). By examining whether self-efficacy belief is based upon actual ability (true belief) or prediction errors (false belief), Study 1 showed that self-deception occurred in the effortless (easier access to answer cues) rather than effortful (harder access to answer cues) cheating opportunity conditions, suggesting high ambiguity in attributions facilitates self-deception. Studies 2 and 3 probed the neural source of self-deception, linking self-deception with the metacognitive process. Both studies replicated behavioral results from Study 1. Study 2 (ERP study; N = 55) found that the amplitude of frontal slow wave significantly differed between participants with positive/self-enhancing and negative/self-diminishing self-deceiving tendencies in incorrect predictions while remaining similar in correct predictions. Study 3 (functional magnetic resonance imaging study; N = 33) identified self-deceiving associated activity in the anterior medial prefrontal cortex and showed that effortless cheating context increased cheating behaviors that further facilitated self-deception. Our findings suggest self-deception is a false belief associated with a distorted metacognitive mental process that requires ambiguity in attributions of behaviors.