Here is the abstract of this study:
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.
Note that these results contrast with these results [PDF] where experiments showed that “presenting brain images with articles summarizing cognitive neuroscience research resulted in higher ratings of scientiﬁc reasoning for arguments made in those articles, as compared to articles accompanied by bar graphs, a topographical map of brain activation, or no image.”
What’s the right answer? Well, it’s not clear but I would bet that people will still science-up their presentations with pictures of brains. They’re cool.