While a special parliamentary committee is currently looking into the effects of screens and social networks on young people, here is what the scientific studies conducted over several years on this subject that is increasingly preoccupying our connected societies reveal. The results of these studies show overall that the use of screens can have harmful effects on the physical, psychological, social and cognitive health of young people, as well as on the development of young children.
Personal use of cell phones in class reduces learning
You would think that today’s young people who have been using these digital tools since childhood would have acquired expertise in multitasking, such as monitoring text messages on their cell phones and responding to them immediately, or even surfing the Internet, while listening to the lecture given by the teacher at the front of the class. Studies instead reveal that this expertise is illusory: students who multitasked obtained much lower scores (sometimes more than 10% lower) than those who did not (i.e. far from their cell phones) on tests assessing nonverbal reasoning (i.e., understanding that is used to solve problems) and working memory (the ability to memorize new information, to process it, to combine it with knowledge already acquired and to recall it later).
“However, working memory is a cognitive function that is central to learning,” emphasizes Fanny Lemétayer, scientific advisor at the Institut national de santé publique du Québec (INSPQ). This would explain why “many studies report that the higher the frequency of digital multitasking during classes and study periods, the lower the school grades,” states the excellent report on screens and hyperconnectivity that Ms. Lemétayer worked on.
“The brain didn’t acquire this new skill in one generation!” she says.
“It is actually impossible for the brain to process two different sources of information in parallel. Their simultaneity would only be apparent and would in fact reflect constant shifts in attentional focus, necessarily leading to a loss of information,” the file explains. To be at its peak, the brain must focus on a single subject.
Even if the student keeps his cell phone off or face down and on silent next to him during class, its mere presence also results in lower performance on tests measuring reasoning and working memory. “Even when it’s off, the cell phone remains a source of distraction, because there are people who continue to write, to exchange, and the student will always want to go see if there’s anything new,” says Ms. Lemétayer.
What about the use of digital devices for reading and note-taking?
Studies have shown that, compared to reading a paper document, reading on a digital device leads to a lower comprehension of the text. To explain this phenomenon, researchers say that readers of digital platforms “tend to adopt a superficial diagonal reading strategy.” In addition, “the digital medium increases the difficulty of navigating through the text because the spatial-visual landmarks of the pages, such as the four corners or the beginning and end, are unstable,” certainly less obvious.
“In reading paper, contact with the document makes us aware of the beginning and the end. There is something at the visual and sensorimotor level that adds information that apparently allows for a better understanding,” adds Ms. Lemétayer.
Studies also indicate that, compared to handwritten note-taking, digital note-taking provides no benefit. “Some even claim that digital note-taking is less interesting than its handwritten counterpart, which requires synthesizing and analyzing what we have been told, which is already a start in learning,” adds Ms. Lemétayer.
Adverse effects on vision
Spending a lot of time looking at digital screens increases myopia. “When we are exposed to a screen for a long time, we strain our near vision. And therefore, we work our distance vision less. In addition, we are less exposed to outdoor light, which is a protective factor against myopia, because the more children are glued to a screen, the less they will play outside,” explains Ms. Lemétayer.
Constant use of screens can also induce what is called digital fatigue syndromes, such as dry eyes, which is due to the fact that “we blink less when looking at a screen,” explains the scientific advisor.
Sleep, physical activity and mental health suffer from screen use
Screens obviously have an impact on sleep. On the one hand, the blue light they emit slows down the secretion of melatonin, the hormone that regulates our sleep-wake cycle. “This is why we recommend stopping using screens one hour before going to bed, otherwise, we can expect negative effects on falling asleep and the quality of sleep,” notes Ms. Lemétayer.
On the other hand, given that the business model of many platforms, such as social networks and video games, is designed to keep us up as long as possible in order to expose us to advertising and compile data on us, this makes us go to bed later. And as a result, this reduces the quantity and quality of our sleep, the scientist points out.
However, by reducing the duration and quality of sleep, intensive use of screens also risks affecting the mental health of young people. This can also be undermined by cyberbullying and violence that these young people may be victims of on the Internet.
Screen use also impacts physical activity, as it often replaces time that would otherwise have been devoted to it. This problem is particularly serious given the importance of physical activity for physical and psychological health.
Screens delay language development
“The most important thing for young children’s development is to have real interactions with significant people. That’s how they learn best. However, the screen often replaces those moments. Whether it’s the screen that the child is using, or the fact that a parent interrupts their interaction with their child because of a notification on their cellphone and they start looking at their cellphone,” notes Ms. Lemétayer.
Studies have shown that a child in front of a screen does not learn anything unless a parent accompanies them and provides feedback on what they have seen, even if they are watching so-called educational applications, she explains.
