Screen Time & Cognition

Years ago, parents were concerned about how many hours their kids spent watching TV. Concerns were largely about lack of exercise, fitness, and obesity.  Now, many people have expressed concerns about the amount of time their kids spend playing computer games and using the variety of communications opportunities now available via one kind of screen or another.  Concerns have been about more than lack of fitness, however, but also about intellectual impact.  Now, here’s some actual research.

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Limiting children’s screen time linked to better cognition


Alex Therrien, Health reporter

BBC News

27 September 2018


Children aged eight to 11 who used screens for

fun for less than two hours a day performed

better in tests of mental ability, a study found.


Combining this with nine to 11 hours of sleep a night was found to be best for performance.

Researchers said more work was now needed to better understand the effects of different types of screen use.

However, they acknowledge that their observational study shows only an association between screen time and cognition and cannot prove a causal link. And it did not look at how children were using their screen time, be it to watch television, play videogames or use social media.



The study, of 4,500 US children, published in The Lancet Child & Adolescent Health journal, used questionnaires to estimate the child’s:

  • physical activity
  • sleep
  • recreational screen time

Children also completed a test, which assessed cognitive skills, including:

  • language
  • memory
  • attention

The study controlled for:

  • household income
  • parental and child education
  • ethnicity
  • pubertal development
  • body mass index (BMI)
  • traumatic brain injury

It found that children who each day had less than two hours of recreational screen time, got nine to 11 hours of sleep, and did at least one hour of physical activity performed better than those who did none of these.


Less than two hours of screen time a

day was the  one factor most linked

to better performance in the test.


Dr Jeremy Walsh, from the CHEO Research Institute, in Ottawa, Canada, said:


“Based on our findings, paediatricians,

parents, educators, and policymakers

should promote limiting recreational

screen time and prioritising healthy

sleep routines throughout childhood

and adolescence.”


Dr Walsh added that more research was now needed into the links between screen time and cognition, including studying the effects of different types of screen time. He said there was some evidence, for example, that video games and educational TV programmes might have cognitive benefits.

In contrast, emerging evidence suggested the use of mobile devices and social media may be harmful for attention, memory and impulse control, he said. However, the authors acknowledged there were limitations to their study, including that the data was self-reported.

The questionnaires were also only used only at the beginning of the study and so did not track how behaviours may change over time.

Dr Kirsten Corder, senior investigator scientist at the University of Cambridge, who was not involved in the study, said it added to existing evidence showing potential negative links with screen time and cognitive development in children. But she pointed out that the children may have struggled to answer the questions accurately.

Dr Corder also said further work was needed to develop more accurate ways to assess the effects of screen time in detail.  She said …


“These results will hopefully stimulate

further research using techniques that

allow researchers to explore how

multiple behaviours may interplay

to benefit cognition and health.”


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As many readers have learned, my wife happens to be clairaudient. Whenever an issue arises for which I think a different – and often wiser – perspective is needed, I ask “D” for comments …


“Human beings, as they’ve developed, over the last 30,000 years, are designed to move and to look out onto the horizon. In doing so, humans look out and look in, so they’re not just looking at one distance.  We also know that being in nature calms humans.  So … 

“The new behaviors, such as looking at a screen, as in the last 70 years, are pushing changes in the brain, which are not fully understood. 

“And the behavior is potentially harmful …


  • “The more people sit, the less they’re moving.


  • “The more they look at one focal point, the less they’ll exercise their eyes.


  • “Having short spurts of information may slow our ability to focus or to understand complex issues.


  • “And the constant need to have a phone in hand is becoming an addictive behavior. That could lead to more time on the phone and less in-person time … and interpersonal communication skills.



“Please think about balancing indoor activities with screen time with activities that stress face-to-face human interaction, honoring circadian rhythm, movement and nature.”


My guess is, new technologies always have their upsides and downsides, and often require some period of adjustment to assimilate that technology into our normal pattern of life. Long-term, I guess that’ll be considered the “evolution of our species.”

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If you haven’t been to our site for a while, someone who does video work professionally – and is a Sierra Club environmentalist – just completed a new 4 minute video for the site’s front page. It’s brief and includes some candid, insightful comments from both residents and prospective residents.

The link to the free “Challenge of Change” book is also on the page.

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