The persuasiveness of a pretty brain

I’m willing to guess when asked what the most attractive part of the human body is, not too many people respond that it’s the brain. But humans have demonstrated time and time again that our introspection into our thought processes is not nearly as accurate as we think, and it turns out that we judge scientific articles as sounder when there’s an image, or even the mention, of a brain.

This study by McCabe & Castel revealed that  people (undergrads in psych classes, to be more precise) who were given an article that included an image of a brain judged it as sounder than those who received the same article with either a graph or with no visual.

The less-convincing graph given to some participants next to the more-convincing brain images given to others.

The less-convincing graph given to some participants next to the more-convincing brain images given to others.

In order to examine whether the articles with the brain images seemed sounder because the images were visually complex, they reproduced the study, giving students either the same brain images or equivalent topological maps (more complex), and found that again, the brain-image-laden articles were rated as sounder.

The more visually complex, but less convincing topological map next to the more persuasive brain image

The more visually complex, but less convincing, topological map next to the more persuasive brain image

In a final experiment, they gave participants the same existing BBC article, either with or without a brain image, and participants who received the image rated the article’s conclusion more highly than those who did not. The images never added any information to the articles in which they were presented, but that fact was irrelevant to students’ judgments. As gimmicky as it might sound, this is worth noting if you want to publish a scientific piece with a broad public impact.

In another study, Weisberg and colleagues gave all participants simple descriptions of psychological phenomena, some with an irrelevant neuroscientific explanation accompanying the general description, and others without. Overall people preferred the explanations accompanied by the neuroscience. The neuroscience seemed to especially enhance their satisfaction with the explanation when the explanation itself was bad. Luckily, this effect did not hold up with actual neuroscientists, who tended to rate explanations lower when they were accompanied by unnecessary neuroscience jargon. Pretty interesting that the inclusion of a few high-level lexical inclusions can significantly alter our perceptions of an explanation, even when those words only add extraneous information…

Bottom line: All of my posts on this blog will contain brain images from now on.



  1. This is an incredibly interesting piece of research! As a rhetorician–always interested in persuasion–I have been thinking for a while now about the scientization of knowledge. Quite a few disciplines that were once humanities-based have become more scientific (witness “the social sciences”). They’re trying to keep up with a society that sees science as more valuable and more concretely true than arguments made with other kinds of evidence. This is especially true of the study of humans and what makes us tick.

    So this research doesn’t surprise me at all. The image of the brain is the most recognizable, accessible way to signal that you’re serious, well-informed, and part of the in-crowd.

    The thing about science is that it takes a lot of training and money to be able to do it at all, so people who don’t have those things have very few resources with which to critique it. But science can still be poorly done, especially when scientists are blind to the socially-created assumptions that shape their research questions, and even their conclusions. (I wrote about this here:

    For what it’s worth, I think science is wonderful, but I don’t think everything we want to know is best understood through the scientific paradigm.

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