Human attention isn’t stable, ever, and it costs us: lives lost when drivers space out, billions of dollars wasted on inefficient work, and mental disorders that hijack focus. Much of the time, people don’t realize they’ve stopped paying attention until it’s too late. This “flight of the mind,” as Virginia Woolf called it, is often beyond conscious control.
So researchers at Princeton set out to build a tool that could show people what their brains are doing in real time, and signal the moments when their minds begin to wander. And they’ve largely succeeded, a paper published today in the journal Nature Neuroscience reports. The scientists who invented this attention machine, led by professor Nick Turk-Browne, are calling it a “mind booster.” It could, they say, change the way we think about paying attention—and even introduce new ways of treating illnesses like depression.
Here’s how the brain decoder works: You lie down in a functional magnetic resonance imaging machine (fMRI)—similar to the MRI machines used to diagnose diseases—which lets scientists track brain activity. Once you’re in the scanner, you watch a series of pictures and press a button when you see certain targets. The task is like a video game—the dullest video game in the world, really, which is the point. You see a face, overlaid atop an image of a landscape. Your job is to press a button if the face is female, as it is 90 percent of the time, but not if it’s male. And ignore the landscape. (There’s also a reverse task, in which you’re asked to judge whether the scene is outside or inside, and ignore the faces.)
To gauge attention from the brain, the researchers used a learning algorithm like the one Facebook uses to recognize friends’ photos. The algorithm can discern “Your Brain On Faces” versus “Your Brain On Scenes.” Whenever you start spacing out, it detects more “scene” than “face” in your brain signal, and tells the program to make the faces you are watching grow dimmer. In turn, you have to focus harder to figure out what you’re seeing, and to succeed at the “game.” In the Princeton face-scene game, college students made errors 30 percent of the time.
If this were a test, they would have gotten a D.
“Internal states are kind of ineffable,” says Turk-Browne, an associate professor of psychology at the Princeton Neuroscience Institute. “You may not know when you’re in a good or bad state. We wanted to see: If we give people feedback before they make mistakes, can they learn to be more sensitive to their own internal states?”
It turns out they can, Turk-Browne says. The key is that, for some subjects, the pictures were controlled not by their own brains, but by someone else’s: meaningless jitter. Of the 16 subjects who got their own brain feedback, 11 said they felt they were making the pictures clearer by focusing, as opposed to four of 16 who watched the placebo feedback. What the scientists found is that only people whose own brains drove the images’ dimming improved their ability to focus. Paying attention, in other words, is like learning basketball or French: Good old-fashioned practice matters.
“I think what’s exciting about this finding,” explains Turk-Browne, “is the idea that certain aspects of cognition like attention are only partly consciously accessible. So, if we can directly access people’s mental states with real time fMRI, we can give them more information than they could get from their own mind.”
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