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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.