What happens in a brain when you read Harry Potter?
Reading about Harry Potter's adventures of learning to fly his broomstick activates some of the same regions in the brain we use to perceive real people's actions and intentions.
In a unique study, scientists who peeked into the brains of people caught up in a good book emerged with maps of what a healthy brain does as it reads.
The research reported has implications for studying reading disorders or recovery from a stroke. The team from Carnegie Mellon University was pleasantly surprised that the experiment actually worked.
Most neuroscientists have painstakingly tracked how the brain processes a single word or sentence. They look for clues to language development or dyslexia by focusing on one aspect of reading at a time. But reading a story requires multiple systems working at once. It includes recognizing how letters form a word, knowing the definitions and grammar, keeping up with the characters' relationships and the plot twists.
Measuring all that activity is remarkable, said Georgetown University neuroscientist Guinevere Eden. She helped pioneer brain-scanning studies of dyslexia but wasn't involved in the new work.
"It offers a much richer way of thinking about the reading brain," Eden said.
There's no turning pages inside a brain-scanning MRI machine. You have to lie still. So at Carnegie Mellon, eight adult volunteers watched for nearly 45 minutes. Each word of Chapter 9 of "Harry Potter and the Sorcerer's Stone" was flashed for half a second onto a screen inside the scanner.
Why that chapter? It has plenty of action and emotion as Harry swoops around on his broom. But there's not too much going on for scientists to track, said lead researcher Leila Wehbe. Wehbe had the idea to study reading a story rather than just words or phrases.
The research team analyzed the scans, second by second. It created a computerized model of brain activity involved with different reading processes. The research was published by the journal PLoS One.
But parsing the brain activity took extraordinary effort. For every word, the researchers identified features the number of letters, the part of speech, if it was associated with a character or action or emotion or conversation. Then they used computer programming to analyze brain patterns associated with those features in every four-word stretch.
They spotted some complex interactions.
For example, the brain region that processes the characters' point of view is the one we use to perceive intentions behind real people's actions, Wehbe said. A region that we use to visually interpret other people's emotions helps decipher characters' emotions.
The team's computer model can distinguish with 74 percent accuracy which of two text passages matches a pattern of neural activity. Scientists are calling it a first step as researchers tease apart what the brain does when someone reads.
Critical thinking challenge: Explain how volunteers read Harry Potter inside the MRI machine