“However I Judge it – I Think it’s a Gut Feeling”: Examining (Un)Trustworthiness Cues in YouTube Videos by Real and Feigned Experts

On social media, misinformation on socio-scientific issues can spread rapidly, yet these platforms are also increasingly used for health and scientific information. Individuals lacking the necessary expertise may present themselves as experts, complicating laypeople’s ability to assess the trustworthiness of these so-called “feigned experts.” This study explores the cues laypeople use to judge the (un)trustworthiness of feigned and real experts in genuine YouTube videos about COVID-19, using semi-structured qualitative interviews with the think-aloud technique (N = 33). The findings indicate that laypeople rely on a variety of cues, particularly when the “channel” is unknown. All participants identified the mentioning of the “expert’s” background (e.g., credentials, affiliation) as crucial for trustworthiness. They compared “experts” to their preconceived notions of scientific experts, highlighting strong expectations for expert communication and behavior. In general, feigned experts were deemed less trustworthy than real experts. The expressed skepticism toward these self-proclaimed experts reflected their deviation from participants’ expectations. However, even in the case of feigned experts, the presence of key cues—such as mentioning the “expert’s” background, combined with additional factors like outward appearance or the use of scientific jargon—contributed to positive trustworthiness assessments. The findings highlight the complexity and challenges laypeople face when evaluating the trustworthiness of (feigned) experts in online videos, particularly when confronted with contradictory cues.