Can a Brain Scan Predict Your Behavior Better Than You Can?

By Andrew Moseman | Discover Magazine

"It would be an advertiser’s dream: knowing the exact location in your brain that indicates whether an ad has worked, and whether you intend to buy that cat food or wear that suntan lotion. Now, some researchers claim they’ve found a region which might predict whether viewers will act on what a commercial tells them.

For a study published yesterday in The Journal of Neuroscience, researchers asked 20 participants to listen to a series of “persuasive messages.” While the test subjects listened, researchers used an fMRI to record the activity in various regions in their brains. The study was small–but researchers say that, with these 20 participants, they could determine many of these listeners’ intentions by looking at a region associated with self-consciousness, called the medial prefrontal cortex.

The subjects listened to messages covering a range of subjects, but the team, lead by Matthew Lieberman at UCLA, was really interested in a public service message about the importance of using sunscreen. Before the brain scans, researchers surveyed the participants about a variety of their behaviors, including their expected sunscreen use for the next week.

After the brain scans were complete, researchers asked about their intentions again and gave participants “goodie bags” that included sunscreen towelettes. But a surprise follow-up phone call a week later revealed that only about half of the participants had lotioned up as often as they said they would.

The researchers then went back to the scans to hunt for hints that might have predicted this “complex real world behavior,” and that’s when they teased out possible predictions in the medial prefrontal cortex. By examining the activity in that area when the listeners heard the sunscreen messages, the researchers say they could predict the real sunblock use of three-quarters of the subjects. Thus, they claim, the brain scans were better predictors of behavior than the subjects’ own projections.
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