On the (non)persuasive power of a brain image

Abstract

The persuasive power of brain images has captivated scholars in many disciplines. Like others, we too were intrigued by the finding that a brain image makes accompanying information more credible (McCabe & Castel in Cognition 107:343-352, 2008). But when our attempts to build on this effect failed, we instead ran a series of systematic replications of the original study-comprising 10 experiments and nearly 2,000 subjects. When we combined the original data with ours in a meta-analysis, we arrived at a more precise estimate of the effect, determining that a brain image exerted little to no influence. The persistent meme of the influential brain image should be viewed with a critical eye.

Look Again: Effects of Brain Images and Mind–Brain Dualism on Lay Evaluations of Research

“…That the findings of Weisberg et al (2008) can still be successfully replicated suggests that this is not the case (Michael et al, 2013). Instead, it seems that neuroscience evidence may enhance the credibility of poorly reasoned arguments, even if brain images per se do not.…”

“…Michael et al (2013) conducted 10 direct replications of McCabe and Castelʼs (2008) Experiment 3. A meta-analysis including these and McCabe and Castelʼs original results found that brain images exerted "little to no influence" on judgments of credibility.…”

“…Nonetheless, studies indicate that MTurk samples are at least as diverse as traditional university and Internet samples, and the data obtained from these subject pools are comparable (e.g., Mason & Suri, 2012;Buhrmester, Kwang, & Gosling, 2011). For example, a well-known study by Weisberg, Keil, Goodstein, Rawson, and Gray (2008), pertaining to the effects of neuroscience information on judgments of reasoning, was recently replicated using an MTurk sample (Michael, Newman, Vuorre, Cumming, & Garry, 2013).…”

The seductive allure is a reductive allure: People prefer scientific explanations that contain logically irrelevant reductive information

“…However, recent work has not yet identified the mechanism by which neuroscience content may have this effect. Although early evidence suggested that neuroscience images influence people's judgments (McCabe & Castel, 2008), these results have failed to replicate (Gruber & Dickerson, 2012;Michael, Newman, Vuorre, Cumming, & Garry, 2013;see Farah & Hook, 2013 for a review). Additionally, neuroscience jargon (e.g., ''fMRI imaging") has no effect over and above references to the brain in plain language (e.g., ''brain scans": Weisberg et al, 2015, Study 3).…”

People consider reliability and cost when verifying their autobiographical memories

“…Jurors are more likely to be swayed by physical (trace) evidence such as shoeprint evidence, for instance, than by eyewitness testimony (Skolnick & Shaw, 2001; see also Ask, Rebelius, & Granhag, 2008). Research also suggests that people find neuroscience explanations persuasive, possibly because such accounts provide evidence of a link between brain activity and behavior (Gurley & Marcus, 2008;Weisberg, Keil, Goodstein, Rawson, & Gray, 2008; see also Michael, Newman, Vuorre, Cumming, & Garry, 2013 for limitations of persuasive neuroscience evidence). Together these studies suggest that people perceive physical evidence to be extremely reliable.…”