Is screen time bad for kids?

Published Dec 5, 2023, 5:18 AM

We’ve all heard the old saying that watching too much TV rots your brain. How much truth is there to this – especially when it comes to kids paying attention in school? Should parents feel guilty about their kids’ screen time? Associate Professor Katherine Johnson has the answers.

Read about the featured study here.

Featuring Associate Professor Katherine Johnson. Katherine's research is in the area of developmental cognitive neuroscience.

Credits: Hosted by Associate Professor Cassie Hayward and Professor Nick Haslam. Produced by Carly Godden and Louise Sheedy. Mixed by David Calf. 

This podcast was made on the lands of the Wurrundjeri people, the Woiwurrung and the Boonwurrung, and we would like to pay respects to their elders, past and present and emerging.

From the Melbourne School of Psychological Sciences at the University of Melbourne, this is PsychTalks.

Hello and welcome to PsychTalks, where we uncover what the latest studies in psychology have to say about how our minds work. I'm Nick Haslam, a professor of psychology here at the University of Melbourne. And I'm joined by my co-host associate Professor Cassie Hayward.

Hi there, Nick. And we're very excited to talk to another expert here from the Melbourne School of Psychological Sciences about their incredible research.

So, Cassie, our focus today, Or perhaps I should say our attention, is on what impacts on our ability to pay attention and stick to a task.

We're on our screens so much these days. Many folks at home might be feeling that our ability to concentrate is in rather short supply.

Yes, and I think there's a particular anxiety that parents share about letting their children play on their phones or their tablets. And I think our listeners are going to be very surprised by the results from this recent study we're covering, because what it shows is that for kids, this screen time might not actually be quite the devil it's made out to be.

Indeed, and to tell us more about it, we're joined by our fellow researcher, Associate Professor Katherine Johnson, who specialises in developmental cognitive neuroscience with a special interest in understanding attention control in children and young people.

Welcome to the show, Katherine. For those of us who are not as schooled as you are in cognitive neuroscience and cognitive psychology, you know what is attention?

Yeah, great question. Um, so the attention generally is the idea that we can focus on one particular thing in a moment in time. So it's our focus, our concentration, and there are a range of different ways to measure that, and to conceptualise that, and we've got a number of different models of attention that are used in the literature.

The models that I use in my research are originally devised by Michael Posner in the US and his colleagues and Ian Robertson in Ireland and his colleagues. So Ian Robertson's work on sustained attention has been preeminent in my research, he was my boss in Ireland.

And so sustained attention is the ability to maintain your attention on a task over a period of time, t hat doesn't give you much feedback, that's quite boring and repetitive and dull. And so you really need to self regulate and maintain your attention deliberately, with that focus in mind.

And then attention more generally, there's lots of different types of attention every second of the day. We are choosing what we are focusing on, so we need to be able to be alert and not sleepy. That's one form of attention, so that alerting feature of being awake and on the ball and ready to go, that's a whole network in the brain that helps you be alert, and it's really, really important for us. We can be overly alert and become fidgety and a bit hyperactive, or we can be very sleepy. So we need to have that Goldilocks range in the middle to perform well.

And then there's another type of attention that's involved in checking. Are we doing the right thing right now? Are we meant to be on task? Are we Are we supposed to be doing this really boring task. Are we still watching for tigers in the forest? Where is my phone? It doesn't matter. I'm meant to be focusing on this task. So this executive control system helps us regulate what we're doing and why we're doing it.

When did you start thinking about the potential impact on screen use of attention problems?

Probably 2019. And it was that research where we looked at screen usage was looking at a big bunch of children who are just from the general classroom. So we weren't targeting children with a particular problem with attention or any other difficulty. We were just looking at our typical classroom and looking at the abilities of children to maintain and concentrate and hold their attention to a task.

And we were interested in how that might relate to their academic performance and what their classroom behaviour is like as rated by teachers. And we are running this large longitudinal study that's funded by the Australian Research Council. This is my colleague, Professor Kim Cornish and myself. She's at Monash University, and we kept getting questions from family and friends about screen use.

It's a really hot topic, especially for parents of little Children where the parents need a break and they need to go and have lunch with their friends at the cafe. And they feel some shame and guilt around giving their toddler or their young child or their primary school child their tablet or their phone to use. So we were interested to see if there was actually any impact of screen use on the child's attention and their behaviour. So it was really like a point of research because we were being asked about it socially.

Hi, I'm a mum of three little kids. And I can tell you there is a lot of concern and guilt around the topic of screen use. Is that concern any different to what we had generations ago about 'There's too much TV or too much video games?' Or is this just a new worry about a similar thing? Or is there something different about screen use?

It's exactly the same problem. It's this idea that we are not entertaining our children ourselves, and so there's something wrong with whatever it is the substitute proxy that we are giving to allow the child to have some time to themselves so that the poor parents and carers can have some time to themselves, so it's exactly the same problem.

TV video games, tablets, Nintendo, whatever it is.

I have all of those things in our house, um, so can we alleviate some of the guilt that parents feel around screen use?

Well, based on our research, this is one study. We can alleviate some of that guilt. Yes, So do you want me to tell you about that research?

I would love for you to tell us about that research, and I'm going to print it out and stick it on in the fridge.

So apps on phones and tablets and computer games are fantastic entertainment for all of us. They are mostly interactive, so there's some information being provided to the child. The child receives information and gives information back, so it might be that they make choices or they respond. And then there's a response back. So these apps have got novel features, and there's a lot of positive reinforcement going on, and some kids actually do have problems in the sense that they continue to play these games for many hours.

And that is a cause for concern. So we were interested to see whether spending time on different types of screens was associated with any classroom behavioural problems and whether it had any associations with the ability of the child to sustain their attention.

We were also interested in the issue of sleep, so we were wondering whether children might be spending time playing games and on their tablet or their parents' phone and not sleeping. So we wanted to ask these two different questions together. Hand in hand. We know that sleep is really, really important for child development of the brain, and it's really important for a child being attentive at school, behaving well and learning well.

So sleep is really, really important. So poor sleep is associated with poorer, efficient attention, poorer, sustained attention. So if you are tired, you are more likely to perform badly on boring tasks. We all have that experience.

There was an interesting hypothesis linking the amount of screen time a child might have with their sleep. And this is the displacement hypothesis, which is just saying that instead of a child curling up under the doona with a book and a torch, they might be playing on their tablet and is that worse? We don't know. So we wanted to ask that question about sleep and screen use and the child's ability to sustain their attention.

And happily, we have this beautiful task that only takes 5.5 minutes. We tested 162 children, and they were about seven years of age, and we found that 94% of the children watch TV and 82% used a tablet. But less than half of the participants used a phone or a video game. So we had 40% of the children had used a phone in that past week, and only 33% had used a video game. So these are seven year olds, and that's probably right. Yeah, we weren't surprised by that.

So just to interrupt. I mean, do you trust the parents to give accurate reports on these things?

A parent of a seven year old?

I'm sure you're very trustworthy. But I mean again, obviously, you can only rely on there's no better data than from the parents, but But were they trustworthy? Do you think?

I think so? Yes, That seemed to be fine with what we would expect. Seven year olds tend to borrow their parents' phones to use them, and they may well have a tablet or have readily access to a tablet. And definitely TV.

This cohort of Children were from across Victoria. So we had a set of children in the metropolitan regions of Melbourne. But we also went out and tested children in regional towns and tiny little rural towns. And so we made sure that we had this beautiful spread of children from across Victoria. Also a spread across SES sectors. And we tested children from government schools, Catholic schools and independent schools.

So, by SES, you mean socio-economic status, sort of rich versus poor schools?

Yes. So we used a measure of socio economic status from the areas around each school.

So we've got this beautiful range of different types of children doing your study. So you've got the reported screen use and then they do this attention task. Right. So your 5.5 minute boring task, how did they perform?

They perform like seven year old. So they made they made quite a few errors. So there's a way that you can measure different parts of performance on this task. So the task is you have one digit, say number one coming up on the computer screen in front of the child.

And then after a second or so, the next digit comes up. And in this version of the task, the next digit is number two, followed by number three, right up to nine, and then it flips back to number one again. Number two number three. And the task for the child is to respond to every digit except number three, so most of the time they are responding. But occasionally they need to

withhold their response, and they can predict when that withhold is coming up. So as soon as there's a flip from the nine back to the one again, they know that three is coming up and they need to withhold the press. But the trick, of course, is that you get lulled into this boring task and you press the three accidentally. So when you do that, that's called a commission error. So you've committed an error.

A child will just go off task so they'll just stop doing the task and they'll look out the window and then they'll go. Oh, I have to do the task and they'll start doing the task again. And so all the digits that they've just missed, they're measures of omission. So they've omitted a response, and so that's a really nice measure of attention control.

They've just gone off task and they've had a moment and then they come back on task again and we all we all do that. But children particularly do that. And then for all the times when they are pressing appropriately, we can measure how fast they've responded, but also how variably they are responding. So we get a measure of their average response time so it might be for seven year old children. That might be 800 milliseconds to respond to the digit. But we want to see how variably they respond.

So if they are about to lose their attention, they may take a while to respond, and they'll have a slow response. And then if they come back on task again, they may rush through and then press quite quickly. And so the longer the amount of screen time

And this is all screens?

All screens, yep. It didn't predict their behaviour in the classroom, so there was no association between how long a child spent on screens and their behaviour in the classroom.

So what you're saying is, in your study, the amount of time that a child spent watching a screen didn't impact their performance on that boring task.

Yeah,

Goes against the hypothesis that it's rotting your brain.

Oh, yeah, but I never believed that. Yeah,

yeah, yeah, yeah, I think there'll be parents who are surprised by that finding who buy into this idea that all screen use is terrible and that must be having some bad impact on their children.

Oh, well, let's talk about that for a second, then, because there are different types of screen use, right? So this won't come as a surprise to us. But video games and tablet and phone have a lot of apps that are really good for children's attention control. So I don't want to foreshadow our results.

But there are lots of really interesting games that are encouraging children to use strategy to respond quickly and accurately and to maintain their attention over time. And these are all things that we want to encourage in children, and the more that we can encourage that through variation in different apps, the better. I think you don't want children on screens for a really long period of time, but there's a lot of benefits to spending time using these creative, strategy based educational apps.

The things you don't want the children to do are watching adult TV that's not designed for children. So that's where they are coming across themes that are not appropriate for their age group and TVs can be - unless it's child friendly and it's designed for interactive work with children - can be a bit mindless, and that's where the brain rotting might come in, where the child is just staring at the TV and not engaging their brain passive. It's a very passive consumption. Yes, I think that's what you want to avoid.

And we should probably say here that passive consumption of content can, of course, happen through tablets and other screens, not just TV. So I guess it's important to keep in mind that regardless of the type of screen, it's that mindless or passive consumption that's a concern.

Yeah, yeah,

And as I said, I've got three kids who are 8, 7 and six, and they do use screens. But I must admit, I've been surprised at how, kind of creative a lot of the games are even on, you know, Nintendo platforms, they can play Minecraft. I was kind of against Minecraft at the start. I now love it because they have to think it's strategy. It's building. It's creativity.

Yeah, it's fantastic

And they love it. It's a game to them, but you can see that there's something more than just play going.

Oh, yeah, that's right. Exactly right. So what we found was the the more time spent using tablets and playing video games, the better the child performed on the boring task, so they made less omission errors. So they went off task less often the more they spent time on tablets and video games.

Is that because they're used to interacting with some type of screen based game, like do they kind of get the?

I'm sure it's a practise effect, but you're practising a system that you want to practise. It's a system where you are trying to engage with the teacher who is standing, I'm sure being amazing, but like, you know, teaching them different bits and pieces that they need to learn, and the child has to sit there and listen and take that information in and use their sustained attention system. And so you want that to be practised.

And if it's on a task that they find engaging that uses their strategy and thinking skills, thinking about the next move to make and how to get around an obstacle or whatever the game is getting them to do, then that's brilliant.

Well, the really clear message that I'm hearing is that screens aren't bad for kids. Sounds to me, at least , In your study, it seems unlikely

that definitely what I heard.

The only thing that you want to pay attention to, though, is that the more time the child spent using tablets, the poorer their sleep quality.

Did you find any evidence for that displacement hypothesis you mentioned earlier? Which I think is the idea that the more you are on tablets, the less time you have to sleep, and that might have negative implications.

Yes, so we wanted to see whether the use of screen devices had a direct effect on sustained attention performance, and it did in the sense that there was a better sustained attention performance with more time spent using tablets and playing video games.

And we were also interested to see if there was an association between time spent on devices and sleep. And there was, so more time spent on tablets was associated with poor sleep quality but not duration.

But then we also tested for whether there was a mediating effect of sleep. So was it the case that children were spending time on tablets that led to poorer sleep quality or poorer sleep duration? That then had an effect on performance on the boring task or classroom behaviour? And that was not the case. So there are two separate effects.

So, Katherine, what I'm hearing is that kids who spent more time on devices were more likely to have poorer sleep quality, not necessarily time spent asleep, but the actual quality of that sleep, and that poorer sleep was also related to poorer classroom behaviour. But those two findings are separate. It's not only those who had a lot of screen time that had the bad sleep.

So your participants in this study are aged 6 to 8. They are quite small. You don't find this relationship between screen use and inattention in class, which is terrific and I think surprising and a really important research message. Do you think you'd find the same things with older kids? Maybe who are engaging in more gaming? Maybe you might find more sleep displacement among teenagers?

Absolutely. That is definitely the case. So previous research has found with adolescents that there is an association between disruptive behaviours and screen use and sleep issues and screen use. And they tend to have more control over their access to screens, Uh, and less parental control.

And that's how nature is meant to be. That's biologically right for adolescents to have that control over their lives. But it can be that if there's less oversight, then some teens can choose to spend a lot of time using screens and not sleep, and then have problems with getting up in the morning the next day and concentrating in the classroom the next day. And they may fall asleep during the day, and then that just leads to the cycle of poor sleep and and poor daytime arousal.

So it's not so much that the screen use for the adolescents is impairing their attentional capacity so much. It's more their attentional performance, given the level of tiredness, something like that.

So in terms of that sleep quality, so you found that the more screen use the poorer quality not necessarily quantity, but poorer quality of sleep. Does that have anything to do with the time they are using the screen? So if we're thinking about advice that you could give parents, is it no screens in the two hours before bed? Or is there anything that can help that sleep quality?

So the sleep literature is quite explicit about that, So the sleep researchers will tell you that try to avoid that blue light from the screens being emitted one hour before going to bed and sleep hygiene. That ability to make sure that your bedroom is free of devices and distractions and that you've got a safe place that's quiet to sleep is really important for a good night's sleep. So good quality of sleep. And then hopefully, if you have a regular period of time when you go to bed each night, then you get a good amount of sleep, so quality and duration will both be good.

Yeah, and I think it's really useful for parents to keep that in mind that that screen use might lead to poorer quality of sleep. What can we look out for in terms of markers of poor quality sleep? We might just think, Oh, they're sleeping 10 hours. That's great. But what can we kind of look out for as an indication that maybe our kids aren't getting the quality of sleep, which may be related to the screen use?

I don't know the exact connections between actual screen use and poor quality of sleep. But the poor quality of sleep coming through in this sleep survey is things like waking up in the middle of the night, not being able to get back to sleep, and being hot and restless during the night, wanting to climb into your bed. That sort of quality is not good.

Yeah, OK, that's good. I think they're good tips for parents to keep in mind, too. Are there any other tips again? I'm putting my mum hat on here. Any other tips we can give parents in terms of regulating screen, use anything around attention that your study would suggest that parents could do to help their kids? I mean, we're not talking about banning screens But what could they do to help their kids have a positive experience with screen use?

Let the children choose the games that they play, but you just regulate it, so check what it is that they're playing and ensure that it's got some brain workings in it. So it's got strategy. It's got problem solving. It's maybe competitive with other friends. So it has a social element and that you can see that they enjoy it because you want them to enjoy that time.

And it doesn't have to be overtly educational, and it can be. If it's creative, that's really good as well. And then you can use it as a positive reinforcement. So if they love playing it, so you get them to do the piano practise first, and then they can play on a device, Um, or you get them to finish their homework first, and then they can play on the device.

Be aware little kids don't have a good sense of time, so if they want to play on their screens between breakfast and getting into the car to go to school or walking to school, be aware of that because you don't want to go 'Yeah, Yeah, You can play your screen device' and then they think they're only going to be playing for five minutes, but it ends up being 20 minutes, and then you're all running late for school, and that's really stressful. So just if you're able to don't let them use it in the morning before school.

But you could use it at the end of the day when they're a little bit tired and you need a break to get, you know, your life organised. And if you can tailor it, then that would be amazing, Uh, as a positive reinforcement for some behaviour that you want them to do.

And is there any room in that screen use for, you know, more passive consumption of fun stuff? Or is it all strategy, creativity? Learning?

Yeah. I mean, again, this is about moderation. Um, so the poor Children they should have some time out as well .

Well, we all we all need to learn to rest, and we all need to learn to have some chill out time. It's really important, and little kids need to learn that, and parents need to role model that parents need to role model that it's OK to have some chill out time and not be pestered by other people. Just as a child needs some chill out time and isn't pestered by other people. If you can build that routine into the day, then everyone is going to have at least some chill out time when they are not being pestered by other people.

And that sets the child up for learning to look after themselves well. Yeah, and that may mean hopefully going outside and spending some time in greenery and nature.

I think that's the other side, isn't it? Just balancing it with exercise and outside and reading. And yes, all those other things.

All those lovely things. So listening to music going for a play in the park go for a walk with the dog. But particularly, this is another side fun. Interest of mine in my research is the benefits of spending time in nature and how that can be beneficial to your attention control and your well being. So if you can get the kids out into the garden and grow things and learn to acknowledge the trees and the birds and the flowers and look at the minute details of the soil and the ants and the bugs and the which kids love.

And working with nature in that way is actually allowing their attention systems to rest and to replenish, and then it's better for them.

That's probably good for the parents as well.

And I think it's important to say here, Katherine, you're not just being an unimperical hippie. You've actually done science on this on the benefits of having greenery around. You want to talk about that a bit?

So this is going to sound wacky. But it's not actually, but spending time in nature. And that can even be with a pot plant or an image of nature, can help replenish your attention control on our boring task. So we've got beautiful work from a former PhD student, Kate Lee, where we did that exactly and showed that just looking at 40 seconds of an image of beautiful nature led to an ability to maintain your attention over time.

But if that break was looking at a concrete roof, then people's performance diminished over time, and we've also done other research with another PhD student, Rose McAuley, where we've had people do our task and then go out for a 15 minute walk in their chosen nature. This is in lockdown. So it had to be like, you know, their balcony or their local park or wherever it was, and then come back and do the task again.

And there were benefits to spending time in the particular forms of nature.

We did find interestingly, though, that if people went into the time spent in nature with a lowered mood, that could lead to worse performance on the task and additional lowered mood. So the starting point of spending time in nature is really important. And so it's not all perfect. It depends on your well being at the start. But for most people, it's a wonderful tonic.

And I think it all kind of fits together with your your work in terms of being outside, exercise, nature and having a balanced use of screen time, which I think parents listening to this would be really happy to hear that you can have you know that screen use isn't always terrible and that you can let your kids use the screens and balance that with some nature time and some exercise time.

Yeah, it's all about just telling myself that, But But, you know, I, I we have a pretty relaxed view of screen time with our kids, but we're all very active, and we live near the beach and we get lots of nature time, and I feel like that balance. It's nice to hear that that's not just something that I've made up in my head, that there is some empirical evidence that having that balance can be really good for the kids.

I agree totally. And the other thing to to note is that if you're at a cafe or a restaurant with your kids and you're meeting your friends and you want to just have some time, adult time, and you pass the tablet or the phone over to the child, that's OK, because your child is going to be fine.

But it also means that you're having fun and you're having stress relief and that you'll be a better parent afterwards. Yeah, so you'll be kinder and more patient and more tolerant because you've had some time for yourself, and then you can then deal with the fluctuations of life in a better way because you're in a better place, so it's OK to use screens with your children.

I think that's great advice for parents

So good to hear that wisdom and balance.

And also, I just wanted to add on a serious note that in this episode we are focusing on the impacts of screens on attention and sleep and school behaviour. But we, of course, can't ignore the risks that parents need to be aware of if their kids are online. In terms of the websites, they are accessing, the apps they are using or who they are talking to.

That's a really good point. I mean, there's cyber bullying and the potential to be talking to people who aren't who they say they are.

All of those things are real risks that parents need to talk to their kids about.

We've talked about some great tips that parents can use for their kids. What about adults or parents? But any adult in general who might want to think about the way they use their screens? Do you have any advice for monitoring or kind of keeping track of our own screen use?

It's a really good question.

It's about self regulation in the end. So the ability to that executive control system that we have, one of the attention systems, So am I doing the right thing right now? Have I been doing this for too long? Is this relevant to my goals in my life? Is this is this, what I'm doing right now, Is this good for my self care and making myself feel OK or is it actually a form of procrastination? And I should be actually getting back to the piece of work that I really don't want to do?

So it's that ability to regulate yourself. It's at the core of all behaviours, and and it's hard to be vigilant and monitor and police yourself. But that's ultimately what we all need to do to make sure that we're not spending too much time on really fun, evocative, addictive things.

And they're designed that way. They're designed that way. Yeah. What about using the actual systems in, you know, screen time limits on phones and things like that. Do you advise people to actually put those in place?

Yeah, Yeah, if they've got problems. For sure. Absolutely. Um, yeah, you can. There's so many good devices available to stop you from, um, using your screen. So, for instance, on your laptop you can ask the Internet to be cut off for a period of time, and you can set that time period so you can't access the Internet, which is good if you need to get a report done. And so you can yeah, use those tools to help you reach your own goals.

Katherine, thank you so much for coming in today. I think just personally, it's been very good. But I think also a lot of people listening will find some really great tips and hints. And I think about alleviating that parental guilt around screen use. And using that more wisely, I think will be really appreciated by our listeners. So thank you.

Oh, my pleasure. Thank you for having me.

Thanks for tuning in to psych talks with me, Cassie Haywood and Nick Haslam. And, of course, our guest today, Associate Professor Katherine Johnson. This episode was produced by Carly Godden with production assistance from Louise Sheedy and our sound engineer was David Calf. If you want to discover more, we've put the links to some really great resources in our show notes. And be sure to check out our other episodes of PsychTalks from wherever you get your podcasts

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