Why We Remember More When We Read on Paper

Source: Geralt/Pixabay

Among my friends who are serious readers (and that’s most of them), there is an almost universal preference for printed paper books over electronic screens. Reasons for this preference range from the tactile pleasure of turning one page after another to the yeasty whiff of nostalgia that emanates from between the covers of a book that has some years on it. One friend insists on reading in the bathtub, which predisposes her to paper for obvious reasons.

Better Comprehension With Paper

In addition to such subjective sensory pleasures as these, reading from paper offers a far more tangible benefit as compared with reading from screens—namely, better comprehension. The vast majority of studies comparing the two reading mediums have concluded that readers simply retain more from reading on paper than they do from an electronic device. While many theories have been proposed to account for this disparity, including “digital distraction” (the temptation to browse or multitask while reading on a screen), the challenge to “spatial memory” of text that is not always located on the same part of a page, and even “rampant self-delusion” in screen readers who overestimate their level of reading comprehension and thus don’t put as much effort into the act of reading, there is no general consensus over why we retain more of what we’re reading when we read from paper. A recent study at Showa University School of Medicine in Tokyo found a possible answer to the question in an unexpected, and to the casual observer purely peripheral, variable involved in the reading experience—sighing.

Citing previous studies that linked visual environment and cognitive performance, the research team sought to find a connection between the visual input of text from an electronic screen and the decline in comprehension of the information communicated through that medium. Given the dominant influence that vison has over other senses in “sensory integration or cross-modality,” they suspected that visual input might also affect brain state and physiological condition, which, in turn, “likely exist as mediating variables in the relationship between the visual environment and cognitive performance.” The physiological condition they chose to investigate as a potential mediator, along with brain activity, was respiration. To explore the relationship between visual environment, breathing, and cognitive performance, they recruited 34 university students for a study that examined the effects of electronic device use on reading comprehension by simultaneously measuring brain and respiratory activity before, during, and after reading.

The 34 participants read novel excerpts on a smartphone and a paper book, which were exactly the same size and weight. Each participant took part in two randomly conducted trials for each of four conditions (smartphone/paper, novel A/novel B), with each trial consisting of four sessions: resting state before reading, during reading, resting state after reading, and reading test (10 questions on the content of the novel excerpts). Throughout the trials, participants were connected to monitors that measured brain function (prefrontal activity) and respiration (respiratory pattern, number of sighs, and metabolic pattern).

Respiration and Brain Activity

As in previous studies, reading on a smartphone resulted in lower reading performance than reading on a paper medium. To try to identify the cause of this decline in performance, the researchers examined the respiration and brain activity data they collected during the reading trials. Some aspects of breathing and brain activity were similar in both the electronic and paper mediums. With both the smartphone and the paper text, the amount of air the participants inhaled and exhaled decreased during reading and breathing grew fast and shallow, while prefrontal brain activity increased in both mediums.

A notable distinction in breathing patterns appeared, however, in the number of times participants sighed. When reading from paper, the number of participants’ sighs increased, while sighing decreased when participants read from a smartphone. Reading from an electronic medium appeared to inhibit sigh production.

Along with this difference in sighing, an interesting difference was also noted in brain activity. While prefrontal activity increased during reading in both the electronic and paper medium, overactivity in the prefrontal cortex was noted in participants reading from a smartphone. Citing reported associations between prefrontal overactivity and “poor narrative content comprehension,” the researchers conducted a path analysis that suggested an “interactive relationship between sigh inhibition and overactivity in the prefrontal cortex” that may be responsible for the comprehension decline associated with reading from an electronic device.

Previous studies have indicated that sighing increases with increased cognitive load. The researchers hypothesize that reading on a paper medium creates a “moderate cognitive load” that may generate sighing, which “appears to restore respiratory variability and control of prefrontal brain activity.” The prefrontal overactivity observed in smartphone reading, on the other hand, suggests an “acute cognitive load,” which may inhibit the generation of sighs and prevent the restoration of respiratory variability and prefrontal activity control.

Blue Light From Screens

When looking for a likely cause of sigh inhibition and prefrontal overactivity associated with smartphone reading, the researchers identified the likely culprit as the blue light emitted by electronic screens. Blue light causes forced sustained attention, due perhaps to the close connection between photosensitive retinal ganglion cells and parts of the brain that modulate arousal and learning. The sustained task attention required of reading from a smartphone may inhibit sighing and lead to overactivity in the prefrontal cortex, which, in turn, diminishes reading comprehension.

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So what is the takeaway from the study for people who spend a lot of time reading? For readers like me who prefer paper already, the findings confirm our preference and give us one more reason to visit our local library or bookstore. And for readers who prefer an electronic device for one reason or another (or on those occasions when those of us who prefer paper books can’t get our hands on them and are forced to resort to our smartphone), the researchers suggest that we may want to pause from time to time while reading and take a deep breath, “since sighs, whether voluntary or involuntary, regulate disordered breathing.” Whether we’re reading from paper or a smartphone, sighing may very well be the key to better reading comprehension.