Science Friday
Hosted by Flora Lichtman and Ira Flatow
Researchers have correlated brain and behavioral changes in kids to increased time on phones and other screen devices.
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Hey, it's Flora Lichtman, and you're listening to Science Friday. As an 80s kid, I spent many hours with this.
And definitely this.
And for sure, this.
But despite a lot of time in front of a screen, the term "screen time" hadn't been invented. People trace the term back to a 1991 Mother Jones article lamenting the role of TV and video games in kids' lives, which now, I don't know, sounds kind of quaint to me, like a TV in the den, Nintendo console, when compared with today's ubiquitous portable individual screens where kids are just one swipe away from this.
I built a giant death trap, which is just one of many traps we've built. And for every trap this contestant survives, he wins $100,000.
Legislators are taking on screens. Last month, Australia banned social media use for kids under 16. Other countries are making similar moves, and states, including New York and Texas, prohibit phonies in school. But what's the science on this? How do never-ending YouTube videos or TikTok reels affect kids' brains and bodies? Do I need to set my kid's iPad on fire? Here with a perspective is Dr. John Fox. He's a director of the Del Monte Institute for Neuroscience at the University of Rochester in New York. And Dr. Jenny Radesky is a developmental behavioral pediatrician at the University of Michigan in Ann Arbor, and she's also co-medical director of the American Academy of Pediatric Center of Excellence on Social Media and Youth Mental Health. Thanks both for being here.
Thank you for having us.
Great pleasure. Thank you.
Well, Jenny, let's start with you. Is all screen time created equal? Like, is there a clinical difference between Elmo versus an AI-generated reel?
Oh, my goodness. Yes, absolutely. Especially in early childhood and middle childhood, the effect of content quality really matters. And of course, it matters for teens as well. You know, if you're watching a whole bunch of doom-scrolling reels compared to a bunch of inspirational videos, it really does make a difference on your mental health. But for kids, little kids especially, the way content is created, the story that is told, the way the characters behave, the way the curriculum is delivered, really makes a difference on whether screen time is either a positive or a negative experience for a child.
Well, what is it about reels that make them so bad? Is it just that there's no story, that they move quickly? Like, what's the problem with them?
Well, short-form media is often engineered to really get your attention very quickly. So it really relies on heuristic, these fast-brain responses that really tap into your automatic ways of thinking. They're not your, like, deeper, rational, value-based thoughts. And so-
That actually makes a lot of sense if you've ever watched a reel.
Yes. That is one problem. The other is how they're delivered. It's a frictionless feed without any, what we call, stoppage cues that help you disengage from media. And that's why we hear from so many parents and teens that they just spend more time scrolling than they planned to, and then they feel guilty and blame themselves.
John, you're part of this big research project that's looking at kids' brains over time. This is a really fascinating project. Tell us a little bit about it.
Yeah, so so I'm part of a project that's called the Adolescent Brain Cognitive Development Study, so it's easier to remember as just A B C D. And it's a pretty extraordinary thing because for more than a decade now, we've been following eleven thousand five hundred US youngsters. And when we when we first recruited them, they were between the ages of nine and ten. And those eleven thousand five hundred children were recruited in a very specific and meaningful way, and that is they were recruited to be as close as we could possibly get to the sort of demographic, socioeconomic, educational background, every sort of feature, ethnicity,
race, and so on, to represent as best we could the actual population of the United States. And so we've been following those those nearly twelve thousand kids now for more than a decade, gathering all kinds of information from them, brain development, neuroimaging. And one aspect of that is is we've been quite fastidious about tracking their screen time and usage, and of course, what happens to them, what happens to their psychological, educational development.
What have you learned?
Well, what you find is really that modest but widespread associations with adverse outcomes are linked to greater total screen time, unfortunately. So high screen. Worse mental health, so depression and anxiety, this clear links there, behavioral problems, poor sleep quality, and reduced academic performance. Even after, again, now, this is an important component of it, because of the fact that we have eleven thousand five hundred kids, most anybody doing this kind of work can account for socio-demographic factors and and all the rest of the other things that might play into into sort of as what we would call confounders.
Now, I just got through a list of things that are bad, right? Mental health outcomes, behavioral problems, poor sleep, academic performance, but the effect sizes, and what that means is how much is it really moving the needle? These are generally small, right? They're not they're not dramatic. So so the news is not like, you know, oh, my God, we're all falling off the the edge of the world here. But they're small effects size, and that means that the large population side, we're seeing a few percentage points here and there moving towards this. And then the other key thing is to say that with work like this, it does not establish causality. Right.
Right. This you found a correlation.
That's right. So you can't say that extreme exposure has led to these. It's possible that some of these things that we're developing anyway lead to children, you know, with depression, anxiety to consume more screen or to engage in more screen exposure. But there's a link, and that's the key point.
Jenny, I know that you study how kids are affected by screen time or some of these correlations as well. What can you tell us?
Yeah, I look at kids' upstream relationships with media and YouTube. So I currently have an R O one from the NIH that looks at two-year-olds, follows them to age three and age four. And at each of those times, we look at what they watch on YouTube. And a lot of them, seventy-one percent of them are YouTube viewers at age two. We look at what they're playing on their tablets, if they have a tablet. And then we also, we try to get beyond screen time by looking at the content, like I just talked about YouTube and mobile devices. And we also ask about how media is used because early childhood is such a time of intense emotionality and tantrums.
And so we developed a scale with my collaborators about how we use media for calming emotions and regulating behavior in young kids. And that is one of the strongest predictors of worse emotional outcomes if we are constantly using tech as a soother for young kids and distracting them from feelings rather than helping them cope with feelings.
Let's pause for a second because that's so fascinating as a parent of young children who. Have high emotionality, as you say.
Yes.
I can see the appeal of saying, okay, my kid's going nuts. I'm in a target or whatever, like, let's get a screen going. Is that what you're talking about?
Yes. Well, so there's a, we ask a series of questions about, you know, in these moments when your child is, is getting really hyper, showing big emotions, you want them to calm down, you want them to be quiet. How likely are you to reactively, like, in the heat of the moment, hand them a mobile device to calm them down? And that is what is linked with worse outcomes. Not just the, hey, I need to cook for an hour and please just put on a few episodes of Bluey. You know, we're talking more about this ad hoc, on demand, anytime a child is distressed or bored, because you can see that that would reinforce this expectation of, I'm feeling bad, I don't know what to do with myself.
Let me take this external source of stimuli and often very high pleasure content. You know, YouTube is filled with, with high pleasure, low friction content that effectively stops the emotion or the behavior, but it doesn't treat the underlying problem.
And those kids are not as good at regulating their emotions. Is that what you said?
Correct. That's what we're finding, especially in the kids who have higher surgency at baseline. And what I mean by surgency is that's a temperamental trait where kids are just like, go, go, go. They want something right away. And that's one thing that we really look at, and, and the ABCD study has been great at this too, is individual differences in your, your relationships with media. Is that not all kids are going to have the same negative or positive impacts from media? And so we really need to look at these fussier babies, these tantruming toddlers, the kids who maybe are more sensitive and more emotional and might need a more careful and intentional relationship or boundaries around media.
Yeah, would just add to the last point that there's clear evidence in the literature really backs up what was just being said, which is that the high quality, purposeful, interactive screen time can actually be very beneficial for learning, creativity, social connection, right? So it's, there are varieties of screen time, rather than just here's the machine and go and let's get the electronic babysitter deployed, you know?
And are those more interactive types of?
Yeah, that's so. So there's a really, really nice bolus of work showing that that kind of, you know, interactive connectivity between two people interacting with the screen. So it can be a really good prop, you know? And of course, you, you, you brought up the idea or the, the idea of different populations, sort of different groups of folks. And I'd like to definitely talk a little bit about that because, you know, what happens is the great group in the middle, the sort of neuro normative kids are going to be resistant to most of this stuff. Maybe there's consuming too much screen time or not doing this or that. And they're, they're going to be just fine, but it's the vulnerable kids at the tails of the distribution that we really need to be worried about.
John, what about kids' brains? Are they, do they change with screen use?
Yeah, so, well, again, do they change with screen use? So it gets us back to that causality issue. So, so for example, you know, some of the work that we, my own group has done with the ABCD dataset is actually looking at gaming addiction. And so, so, right, so, so lots and lots of kids, maybe all kids or close to all kids, play video games. And for most of them, it's fine. It's not a big deal. I mean, my own brothers, my own kids played video games. And, but there's a coterie of youngsters out there where it just jumps the shark and they just can't not do it. And in the same way that, you know, in previous generations, there's kids who went on to develop addictions for alcohol or cocaine or whatever it was.
Video games is another variant of that highly compelling, you know, thing that can be very hard to put down. And in those situations, when we look at that tail of the distribution, these kids are just doing it so much at the time, all of the time practically. We find really clear evidence, for example, from neuroimaging, that their reward processing circuits are not working well. So, so we found a normal reward processing in what's called the chordate nucleus. It's part of the basal ganglia that was associated with symptoms of gaming addiction in, in young adolescents.
Um. In the broader group, there the neural imaging research and the A B C D data. And again, we know we have so much of it at many time points. So we got uh structural and functional neural imaging when they were nine and 10. And again, two years later and again, two years later after that. So we had this incredibly deep structural functional uh data sets. And what what you find out that there are structural and functional brain correlates of screen media activity that, you know, show uh screen media related patterns in cortical thickness and gray matter that relate to cognitive performance and these kinds of what we call externalizing behaviors.
Uh. So so it the the data really point to what would be sort of a complex brain behavior association that really needs to be to be looked into. And again, we have to go back to that causality piece, which is, you know, is it the case that the certain brain structural development predisposes you to use the screen more? Or is it the screen use itself is changing how the brain is being structured? I think most people would lean on the second one there, to be honest with you. Um. But, you know, that we don't have that information. And I did want to add one other thing that we didn't talk about, which is, of course, there is a really clear correlation between increased screen time and body mass index and fitness. And that, I think, is someplace where we do have to worry.
We're all fully aware of an obesity crisis uh in our youngsters in the United States. And there's a clear link to how much screen time uh is being consumed there. And so those physical health risks risks are are real and we need to get our kids moving. And so anything that would get our kids out moving uh would be on the positive side of the ledger for me.
Hmm. We have to take a break, but when we come back, is there hope for us and for our iPad kids? Don't go away.
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John, last month, a neuroscientist testified in front of the Senate that screen time is leading to cognitive decline in kids. And, you know, this is like going viral. People are sending this to me. That for the first time in modern history, Gen Z is cognitively underperformed compared to the previous generation. And screen time is to blame, importantly, and at least in this clip. Is that true about Gen Z's performance?
Not that I'm aware of, to be perfectly honest with you. I, you know, I don't like these henny-penny, the roof is falling in kinds of things. I think, you know, I mentioned before, I mean, yeah, we find that there are harms here. But we also find many circumstances where there's good. So the, the science does not support a simple, "Screen time is good" or "Screen time is bad" view. There's, there's nuances to this. There's areas for concern, but, you know... I'm old enough to remember when a phone came to my house and it was going to be the death of the use. The TV showed up, that was going to kill us all. Comic books. We had, you know, rap songs and hip hop were going to destroy us all in the eighties.
Kids rolled on and they got smarter and the world is fine. I look at my own kids, I look at their friends, they grew up in the screen use era, the video gaming era, and they're fine. They're smart. I think we'd want to back off those really disaster scenarios because I just don't believe that those are true. What I do think is that there's, you know, there's reason for us to worry a little bit and to watch out for the, again, those kids that are vulnerable, that are in the tails of the distribution, who really may may suffer from this.
Jenny, is there data that we're missing that we need to understand this problem better? Like from the platforms, for example?
Absolutely. And, and, you know, Flora, I was another witness during that Senate Commerce hearing. But the things I say are usually a little bit more measured, so I usually don't get soundbites that go viral on social media. But what I will say, what I said, that was a hearing about ed tech. And I think that people are pretty frustrated with the way, you know, if you have kind of sloppy or not thoughtful deployment of a technology that's not designed with kids' needs in mind, but might be designed with profits in mind, then you wind up with more risk of harm. And I think what we were talking about in that hearing is some kids are just using tech in a very distracted way, or in a way
that's displacing other important social or learning opportunities in the classroom. It's a very complicated conversation and there are solutions. I think when it comes to You know, trying to move forward in a positive way for kids. The sorts of brain science that John is talking about that we're worried about the effect of tech on kids' brains that sometimes can make parents feel anxious, too. But it also is a source of power. Everything you do rewires your brain, right? If you can change your habits. I'm a developmental pediatrician. I work with lots of kids with learning disabilities, autism, ADHD. If you work hard at things and you practice and you get therapy, there's so much growth that can happen.
So that's just one positive spin I wanted to put on, you know, what is a very stressful topic. Back to your question about platform data. As, you know, I do a lot of policy translation work. I worked for the Federal Trade Commission last year. We really don't have all of the data that helps us make decisions about what's best for kids in the digital world because the platforms hold so much of it. They've been running experiments on different design features and seeing, you know, usually measuring, oh, how does this notification pattern or this endless scroll affect user engagement? Or how much time someone stays on my platform?
Or, you know, how much they come back day after day? Those sort of metrics, from a clinician or a researcher's standpoint, I'm so curious, like, oh, you have data about which kids are on TikTok and Snapchat overnight. I know you do. And so you have data actually about the way that some of your design feature changes have changed youth well-being. But we don't have laws that mandate transparency for that data or accountability. Like, okay, big tech platform. If you roll out a new feature that you find actually worsens some sort of like compulsive usage behavior in teens.
You should be, you should have a, what we call a duty of care, you know, a mandate to roll that back and maybe say, no, we're not going to do that because we're seeing that teens are not sleeping as well. So I do think that a lot of the debates about social media and mental health have actually gone with, you know, we've been flying blind a little bit because all we have is our scientific and academic data. We don't have a platform data that actually, you know, has causal experimental studies that they've done.
And what about these, these bans? Are those, are these bans for screens in schools or, or social media bans? Is, do you think that's the answer or would you prescribe something else?
You know, I tend to be someone who likes to focus on design that if we can design technologies around the way that young people experience the world and benefit from interaction with technology, you're going to have lower risk, you're going to have more opportunities. And right now, a lot of tech design is not around what is meeting kids' wellbeing. It's around what is meeting their profit margin or their ad impressions or, you know, their engagement metrics. So.
Yeah, they're designed to be addictive. They, I mean, these platforms want you on the platform as long as possible.
That's how they make so much quarterly revenue. So if we were to change the design elements that affect these mechanisms of harm, right? What are the mechanisms of harm? Staying on too long, seeing inappropriate or harmful content, being bullied or contacted by a stranger who is inappropriate with you. If you could change the design features that don't allow a lot of those mechanisms of harm, you would allow teens to have the benefits of social media types of platforms or gaming platforms without all of these risks that have kind of gone, you know, without any regulation over the past 10 years
that we're just now kind of keeping, catching up to. So that, that is more my approach. And, and the approach at our Center of Excellence is let's improve the design. Let's get the under 13s off of social media, please, because there is pretty good evidence that, that starting social media under age 13 is associated with higher risk of depression and more problematic use patterns. But for the teenagers who have this real developmental drive to connect with each other, let's just create healthier spaces where that can happen and they won't be open to manipulation.
John?
Yeah, couldn't agree more. I think, you know, I'm personally not big on banning stuff because I think we've tried that in policy many times and it just doesn't work. You know, that said, you know, the motivation to do these bans on some of those countries, I think it comes from a good place. Obviously, they're trying to protect the kids and that experiment has yet to be run. We'll see where it leads. We should be collecting data to understand if there's really an upside to it. My worries would be that the kids that are most vulnerable to this stuff are the ones that are going to be able to find their way around it. And then I worry about inequities, which is
that there are places where those screens are the only source of really good information. And going back to that basic idea, you know, that there's good screen time and there's bad screen time. And when you do a ban, you take both of them away. So I like the way Jenny said it, you know, let's work on design so that most of it is good screen time.
Dr. John Fox is a neuroscientist at the University of Rochester in New York and Dr. Jenny Radesky is a developmental behavioral pediatrician at the University of Michigan in Ann Arbor. I'm very glad to know that a few blueies while I'm making dinner isn't the worst possible thing. So thank you to you both.
Absolute pleasure. Thank you so much.
Yeah, it's a great conversation.
This podcast was produced by Kathleen Davis and if you're enjoying this engaging no-screen-required media experience, please consider leaving us a review on your podcast platform of choice. It actually does help the show. Catch you tomorrow. I'm Flora Lichtman.
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