Neurocognitive mechanisms of source credibility: how work experience and patient ratings modulate the processing of medical veracity cues.

INRODUCTION: Source credibility is fundamental to how medical information is processed,yet the underlying neurocognitive mechanisms remain poorly understood. We investigated how two credibility cues - a doctor's expertise (years of work experience) and aggregate patient ratings (star ratings) - modulate brain responses to veracity cues ('True' vs. 'False') presented after health- related headlines.

METHODS

We recorded EEG from 36 participants while they evaluated true and false headlines across various medical topics (e.g., vitamins, GMOs, vaccination). Each headline was paired with a fictional doctor's profile that systematically varied in expertise (work experience) and patient ratings (star ratings).

RESULTS

Behaviorally, while both doctors' characteristics predicted opinion change and persuasiveness of veracity cues, patient ratings exerted a significantly stronger effect than work experience only on the persuasiveness of veracity cues. Critically, 'False' cues elicited a significantly stronger FRN(RewP)-like response when delivered by highly rated doctors compared to less rated ones; no such modulation was observed for 'True' cues. Source localization using standardized low-resolution electromagnetic tomography (sLORETA) identified frontal and posterior medial cortices as the likely neural generators of this effect.

DISCUSSION: Overall, our findings suggest that source credibility cues modulate the effectiveness of medical veracity feedback, revealing distinct neurocognitive mechanisms that underpin how credibility differentially shapes the processing confirmatory and disconfirmatory cues.