How Fast Is Too Fast? The Neuroscience of Early Childhood Screen Exposure and Brain Development
Presentation by Dr. Sam Wass, University of East London
Transcribed from House of Lords Early Years online event
Hi everyone, great to be here. Today I’m going to be talk about a project which, as Julia mentioned, we're just setting out on together, funded by the Leverhulme Trust. It’s very much a neuroscience topic for reasons I'm going to be talking about. I'm going to go into a bit of detail on the neuroscience, why we think it's important, and what we're hoping to find out from doing this.
Okay, so this is my daughter, Rose, she's now four. This picture was taken a couple of weeks ago, but the story for this research started about two and a half years ago when she was about 18 months.
We were on a long-haul flight. Five hours in, both of my children were on what felt like their millionth trip across my shoulders from one side of the row of chairs to the other, bouncing up and down, treating my spine like a human pogo stick. I felt like I was gradually getting squashed into my chair as my spine was getting more and more squashed up. like a bent nail.
And finally, out of desperation, I did what many parents do: I pulled out my iPad, on which we downloaded some screen content and I put it on. Rose was 18 months, she'd never seen anything like that before. We hadn't let her to do this before. This was really a sign of desperation.
And the effect on her was astonishing. I'm sure many of you will have seen similar things with young children.
Straight away, she went from what we call hyperkinetic- constantly moving, constantly kind of agitated - to completely motionless. She didn't move a muscle for the whole time that this thing was on. Which I found astonishing in itself.
Particularly since she was 18 months, the content was such that I was pretty sure she didn't have the first idea what it was that she was watching. She didn't actually understand any of the content that was being presented. So this really intrigued me.
What was it about this screen content that I was giving her that had this radical effect, even though she didn't have a clue what it was that she was watching? That was the first thing I noticed. The second thing was that it turned out to be a really bad idea long term. She was absolutely motionless for the time it was on - but the minute it came off, her mood was 20 times worse. She was much more agitated, really irritable, fidgety, making the rest of the pain journey painful indeed. So that kind of got us interested in what we're going to be talking about today, particularly this idea of what's different about early screen use.
So I'm sure you've all heard a massive amount about increased rates of teenage mental health diagnoses going up. The research on social media, as I'm sure a lot of you know, is actually much more equivocal than you'd hear sometimes from the newspapers. The really
careful scientists and colleagues of mine show that in fact, the effects of teenage social media use on outcomes are mixed bag.
Where there’s a lot of work that still needs to be done, though, is looking at early years. Since 2010, what are the long-term effects? Every parent now has a telly in their pocket. iPhones came out in 2010. Since then, we've had a massive increase in the amount of screen exposure from very young children. These children are now the ones who are turning into teenagers. And there are some important tasks to do here.
But to do that, as I say, we have to be using kind of tricky techniques. This is why we don't know the answer to these questions yet. I got funding for my research at the Institute for the Science of Early Years in East London from various institutions. We study children's brain activity in real time during face-to-face interactions or while they watch screens. We're exploring different types of environments, including physical spaces and urban areas. We're in East London. It's an amazing mix of urban life and digital culture.
OK, so put your belts on. We're about to have three minutes of solid neuroscience. So I hope you've had a nice cup of coffee.
OK, so this is what we're looking at in a grant. Our brains function as machines that generate predictions. So moment by moment, as I'm speaking, your brain is generating a prediction of what word I'm going to say next.
If I say "cabbage" without warning, your brain reacts to that word in a particular way since it doesn't fit the context. So that's what we measure. So that's how we know that your brain is generating a prediction.
All forms of learning, everything our brain does, operate in this way. To improve learning, I need a space where I can sometimes guess what comes next, but not always. When I find myself in a boring situation, like staring at a blank wall, I know exactly what I'll see next. Each time I predict I get the prediction exactly right – so I don't learn anything from it. So I find that quite aversive.
In unpredictable situations, like a lecture on theoretical physics that I can’t grasp, I also don’t learn much. My predictions are never right - so I find it aversive, so I don't learn as much from it.
We look for situations where you can understand and predict what might happen next sometimes, but not always. That's part one.
As time goes on, our brains gather knowledge and experience. They practice and improve. This helps us make better predictions. So then we seek out situations that are progressively more and more unpredictable.
This impacts our growth throughout our lives and as a species. We haven't changed through screens, which we'll discuss soon. Throughout our development, humans have shaped our
environment. We've altered how we interact and what information we receive. This has made our surroundings more unpredictable and complex.
People have always sought new experiences. From ancient hunter-gatherers who traveled for weeks to meet once a year, to the rise of urban living, this quest for adventure continues. 200 years ago, 5% of the world's kids were born in cities. By 2050, it will be 70% of the world's children born in cities.
Through to now, this idea of screens, which is all about this type of fast-paced, immediate feedback. And they're getting faster and faster, and more and more immediate over time. That's what people want.
And it's driven by this learning mechanism. The first time I go on a screen, it's stimulating; it keeps me in my zone. The more time I'm on screens, the more I get used to predicting what's going to happen, the more I need it, even faster.
So all the way through, in lots and lots of different ways, it's not only through screens. We’ve changed our environment as we developed. This change comes from a simple learning process. It forms the essential basis for everything about how our brains work.
So what about children? What about kids? There aren't any regulations in the UK at the moment. The American Academy of Child and Adolescent Psychiatrists has strict regulations. In France, there is a movement saying no screens at all for the under six.
What makes predictability and screens important for understanding early development? So, again, a little bit more neuroscience, but then I'm done with the neuroscience.
Young brains are, in simple terms, chaotic and interconnected to an extreme degree.
From ages two to five, we enter a phase called synapse proliferation. During this time, we create many different neuronal connections. Your brain has the most connections when you're between two and five years old. After that, the number of connections starts to decline. And because of that, young brains are slow and inefficient.
So to give an example, the fastest that an adult brain can see is 10 frames a second. If you do the same thing for a 15-month-old, the fastest they can see is one frame per second. So anything that's been and gone in less than a second, they can't see.
And I used to love doing that experiment with my kids. You hold a ball up, and you drop it, and they're like, "Where did it go?" They find it down there without warning. They can't see it while it's moving.
So young brains are slow, messy, and inefficient. And it's because of that that the same learning mechanism occurs. People learn best when they can sometimes predict what will happen.
For a young brain that is slow, messy, and inefficient, it looks for the easiest option. Because even when it's as easy as it can be, it still only gets it right some of the time. So that's why babies—this is my son when he was in this phase; he loved to bang spoons on the table.
They do the same thing again and again. Their brain is very messy, inefficient, even with a simple prediction. If I make this movement, what am I going to hear? Their brain still only gets it right half the time.
And then they go on to more and more. They enjoy many kinds of fun interactions. This includes peekaboo and telling tales. So we have this transition that happens during the course of early life.
Babies learn best from things that are very predictable. They like knowing what will happen next. As they grow older, they improve their prediction skills. So, they begin to look for more unpredictable situations. This is my son Freddie, age six.
One time a few months ago, I kept thinking about what would happen if he shoved a pea up my nose. And I had a picture of him with a pea up his nose here, but I thought it was excessive for the House of Lords. So yeah, okay.
So this is the transition – what we learn most from is predictability during early life and unpredictability during later life.
The problem, then, is that we’re giving a lot of screen exposure during early childhood – which, as I said, is very fast-paced and unpredictable – to young children at a time when slow-paced predictability is what they need. Their brains need something else.
Yeah, okay. So that's what we're going to be exploring the effects of in this grant with Julia over the next few years. We're going to track how babies' brains process information in real time. This is crucial to our question, but we don't know the answer yet.
How fast is too fast for young brains? It's a fundamental question, and we have no idea what the answer is. There aren't any studies on this at the moment. This matters.
What about the fact that my daughter felt so irritable after her screen time, as I mentioned earlier? Well we think that what’s happening is here is that, when I can't predict what happens next, my brain goes into high-alert mode. This is an inbuilt evolutionary response. My brain can go into hypervigilant mode. It functions as an emergency mode, and the reasons for its existence are clear. I can't predict what is going to happen next.
It's possible – we don’t know yet – that this might link to research on how early screen use impacts later life mental health.
These are a couple of papers that came out on this topic; I know quite a few researchers who are doing this. We don’t know if this is the right mechanism, but there is a clear relationship. So that's what we're going to be looking at.
How fast-paced is too fast-paced for young brains? How do we raise awareness about this among the industry? Many content producers will want to know the answer to this. Nobody wants to produce content that the brains of the people watching can't keep up with. If we can use this method to see what "too fast" means, it could be very interesting. In a room full of experts, this might shape policy. So yeah, stay tuned for more.
Thank you very much.
