Brain Scan Studies at Carnegie Mellon Use Harry Potter Book to Create Computational Model of Reading
To help them identify how different regions of the brain are activated when people read, Carnegie Mellon University (CMU) scientists conducted a study in which participants read a chapter of Harry Potter and the Sorcerer’s Stone. According to a study report published in the November 26, 2014 edition of the online journal PLOS ONE, the CMU researchers performed functional magnetic resonance imaging (fMRI) scans of eight people as they read a chapter of the Harry Potter book. The goal was to determine how the brain carries out complex story processing and understanding.
An analysis of the scans resulted in the first integrated computational model of reading that identifies which parts of the brain are responsible for such sub-processes as determining the meaning of words, and understanding relationships between characters. According to the research report, analyzing multiple sub-processes of the brain at the same time is unprecedented in cognitive neuroscience.
“At first, we were skeptical this would work at all,” said Tom Mitchell, PhD, department head of the Machine Learning Department in CMU’s School of Computer Science. “But it turned out amazingly well, and now we have these wonderful brain maps that describe where in the brain you’re thinking about a wide variety of things.”
According to the study report, the model is still inexact, but might someday be useful in studying and diagnosing reading disorders, such as dyslexia, or speech that has been impacted by a stroke. Educators might also be able to use the computational reading model to identify areas of trouble for students who are learning a foreign language.
“If I’m having trouble learning a new language, I may have a hard time figuring out exactly what I don’t get,” Mitchell said. “When I can’t understand a sentence, I can’t articulate what it is I don’t understand. But a brain scan might show that the region of my brain responsible for grammar isn’t activating properly, or perhaps instead I’m not understanding the individual words.”
Researchers at Carnegie Mellon and elsewhere have previously used fMRI scans to identify activation patterns associated with particular words, phrases, or even emotions. However, these have always been tightly controlled experiments, with only one variable analyzed at a time. The experiments were unnatural, usually involving only single words or phrases, but the slow pace of fMRI—one scan every two seconds—made other approaches seem unfeasible.
The CMU research team was reportedly convinced that multiple cognitive sub-processes could be studied simultaneously while people read a compelling story in a near-normal manner. They believed that using an interesting passage from a book as an experimental stimulus—in this case, a chapter about Harry Potter’s flying lesson—would provide a rich sample of the different word properties, which could help to reveal which brain regions are associated with these different properties.
The research team devised a technique in which people see one word of a passage every half second—or four words for every two-second fMRI scan. For each word, they identified 195 detailed features—everything from the number of letters in the word to its part of speech. They then used an algorithm to analyze the activation of each cubic centimeter of the brain for each four-word segment.
Researchers reported that the algorithm was able to associate certain features with certain regions of the brain. They found that movement of the characters in the story—such as when they are flying their brooms—is associated with activation in the same brain region that we use to perceive other people’s motion. Similarly, the characters in the story appeared to activate the same brain region we use to process other people’s intentions.
Additional information about this and related studies may be found on CMU’s School of Computer Science website.
Source: Carnegie Mellon University