Overclaiming and the medial prefrontal cortex: A transcranial magnetic stimulation study

Abstract

The tendency to claim more knowledge than one actually has is common and well documented; however, little research has focused on the neural mechanisms that underlie this phenomenon. The goal of the present study was to investigate the cortical correlates of overclaiming. Transcranial magnetic stimulation (TMS) was delivered to the medial prefrontal cortex (MPFC), supplementary motor area, and precuneus during the presentation of a series of words that participants were told made up a cultural IQ test. However, participants were not informed that 50% of the words were actually fabricated. False claiming was reduced following MPFC TMS. Furthermore, reaction time decreases following MPFC TMS indicated that participants engaged in less reflection during the task, suggesting a potential reduction in social monitoring of behavior.

Preliminary Evidence of the Role of Medial Prefrontal Cortex in Self-Enhancement: A Transcranial Magnetic Stimulation Study

“…We have previously found using a similar paradigm that the response rate of ‘knowing’ words is not different between fake and real words, which results in a significant amount of false positives [ 5 ]. Similar to Palhaus’s findings [ 33 , 34 ], we conclude that faking knowledge is socially mediated and that the risk of being seen not knowing something is greater than claiming to know something that you do not.…”

“…The MPFC plays a critical role in testing reality [ 19 , 38 ], self-knowledge [ 39 , 40 ] and more specifically for this study, falsifying one’s reported knowledge [ 5 ], abilities and traits [ 29 ] as well as monitoring social reactions of others in regards to the self [ 41 ].It is therefore not surprising to observe disruption of the MPFC has an influence on false responding. Because TMS had an influence on fake words, but not real words, we speculate that disruption of the MPFC is not uniform in its cognitive influence.…”

“…The methods employed were those similar to Amati et al [ 5 ]. The list of words (both real and fake) was divided into 4 blocks containing 36 words per block ( Table A1 ).…”

“…Self-presentation is often steeped in deception, a critical component of social communication in humans. Snyder [ 4 ] in fact described monitoring of the self as the process through which people regulate their own behavior in order to be perceived in a favorable way and implicated that self-awareness had a primary basis in self-deception [ 5 ].…”

“…There is evidence for a causal link between the MPFC and overclaiming. Specifically, when transcranial magnetic stimulation (TMS) was delivered to the MPFC, bouts of overclaiming were significantly reduced [ 5 ], which has also been observed with tDCS (transcranial direct current stimulation [ 28 ]). Specifically, by temporarily inhibiting the MPFC with single-pulse TMS, rates of overclaiming went down significantly compared to Sham TMS.…”