Reading stories on physical books may require less brain effort than reading on digital screens, according to a Japanese study.
The research, published in the journal PLOS ONE, provides neurological evidence showing how different reading formats can affect how the brain processes and understands stories.
The study was conducted by researchers from the University of Tokyo, led by Kuniyoshi Sakai, a professor of language neuroscience. The team observed 25 undergraduate and graduate students between December 2023 and September 2024.
To examine how reading formats influence comprehension at the neurological level, researchers used Japanese manga, citing its visual narrative structure that helps facilitate scene understanding.
Participants were divided into two groups: one read the first half of a manga in print, while the other read the second half on a tablet as an e-book.
After the reading sessions, participants were asked a series of questions while their brain activity was measured using functional magnetic resonance imaging (fMRI).
“The questions included simple ones and complex ones, the latter of which required comprehension of both parts of the story. But the first story was given to participants on different mediums, paper or e-readers. During questioning, we measured brain activations by using a magnetic resonance imaging (MRI) scanner. This method is called a functional MRI (fMRI). The fMRI technique actually measures the amount of local blood flow in the brain reflecting neuronal activity in a particular region. We found some interesting differences in activity between the two test groups,” Sakai said.
The researchers found that while participants answered accurately in both formats, those who read the first half on a tablet took longer to respond—by an average of 1.28 seconds.
Meanwhile, participants who read the material in print showed stronger brain activity in both the left hemisphere, which governs language, and the right hemisphere, suggesting that reading on digital devices may place an additional cognitive load compared to reading on paper.
“The advantage of paper is not only about memory, attention and emotional engagement, but about language and thought because it involves careful reading and thinking processes,” Sakai said.
He added that similar results would likely be observed in other forms of reading.
“The same results would likely be obtained for reading novels, because storylines and contextual flow are basically the same between manga, novels and other written material. One important advantage of using manga stories in our tests was that manga has visual narratives, which provide rich pictorial information that facilitates the comprehension of scenes,” he said.
