The Swedish government recently imposed restrictions on 
devices in classrooms and a return to physical textbooks . This policy was prompted by concerns about declining student test scores and the negative impact of increased screen time .
Is this anxiety reasonable?
To address this issue, it’s important to remember that the notion of reading as easy is a fallacy. Reading is, in fact, the most challenging task a human being can learn—a skill that requires formal education and years of intensive practice to achieve full mastery.
In contrast to speaking, reading is not a skill that is biologically ingrained in us from birth.
Why is reading complicated?
To understand the complexities of reading, one must first understand the physiological aspects of the reading activity.
When you read a sentence, your eyes make a series of rapid movements from one word to another known as saccades . During this process, visual information is inhibited and only reactivated for brief intervals called fixations—moments when the eyes stop moving.
Various experiments measuring readers’ eye movements have shown that we tend to fixate on most words. This is because our capacity to extract visual information at each moment of fixation is very limited.
In left-to-right languages like English and Indonesian, our ability to recognize the characteristics that distinguish one letter from another is limited to a small area in our visual field, called the perceptual span. This span extends from 2–3 letter spaces to the left of the fixation point to 8–12 letter spaces to the right of fixation.
This imbalance in span reflects the shift in our attentional focus as we navigate text. The pattern shifts to the left in languages that read from right to left, such as Arabic. Furthermore, the size of this perceptual span is also smaller in character-dense writing systems, such as Mandarin.
Various eye – tracking experiments and brain scans have shown that it takes time for us to identify each word. It takes about 60 milliseconds (one thousandth of a second) for the word to travel from the eye to the brain, and the brain needs an additional 100–300 milliseconds to recognize the word.
This biological limitation limits our maximum reading speed to only 300–400 words per minute. This depends on the difficulty of the text and each person’s comprehension capacity.
Proponents of speed reading methods actually only teach skimming techniques. At this point, reading comprehension declines at a rate inversely proportional to speed.
Reaching the upper threshold of reading speed requires years of practice before mastery. This is because the activity requires a network of brain systems—from visual aspects, attention, lexical identification, linguistic processing, to eye motor movements—to work simultaneously and in a highly coordinated manner.
Thus, any factor that hinders this coordination will automatically erode the reader’s absorption and understanding.
The impact of reading on digital screens
So, what are the consequences of reading on a digital screen?
On certain devices, such as e-readers , there’s little difference between digital reading and reading a physical book. This is because both formats support the mental processes required for good reading skills.
More questionable devices are those that cause distractions (such as news sites interspersed with ads) or those with poor text formatting—for example, centered text with excessive or uneven spacing between words. This latter formatting flaw is extremely rare in paper-based text.
Although the impact of these two factors remains understudied, our current understanding of human cognition is sufficient to make informed predictions.
For example, images and audio that are unrelated to the text—such as pop-up ads —can easily distract attention. Unfortunately, children lack the executive control in their brains to ignore these distractions.
The implications are very real for children struggling to comprehend the meaning of a reading. Their comprehension will decline drastically because they have to expend extra energy to ignore distractions, or because they don’t yet have the mental coordination to recognize that their reading focus has been disrupted.
Various eye-tracking experiments have also shown that many digital environments, such as websites, can trigger certain reading strategies, such as skimming or simply hunting for specific information.
These various techniques can reduce overall reading comprehension. This possibility should be a cause for alarm for children, considering that it takes years of practice to align the mental systems that support adult-level reading skills.
Such concerns have recently gained increasing attention. The COVID-19 pandemic forced a shift to online education a few years ago, triggering a dramatic surge in digital reading activity. While this shift was driven by necessity, its long-term impact on literacy skills remains a mystery.
So far, eye tracking research has only been possible on computer screens. However, new technologies are emerging that allow us to directly compare eye movements and comprehension levels between reading on a device and on physical paper.
Given that reading ability is a determining factor for a person’s educational future, socio-economic status, and well-being, the urgency of examining the long-term impact of this digital reading trend should not be underestimated.
Author Bio: Erik D Reichle is Professor of cognitive psychology and Lili Yu is a Senior Lecturer, Cognitive Psychology both at Macquarie University
