How Screen Time Impacts Brain Development with Dr. Heidi Allison Bender

Welcome to Health Matters – your weekly dose of the latest in health and wellness from NewYork-Presbyterian. I’m Faith Salie.

How does screen time impact our children’s brains? That’s the question we asked Dr. Heidi Allison Bender, a neuropsychologist at NewYork-Presbyterian/Weill Cornell Medical Center. 

 In this age of smartphones, social media, and endless YouTube content, technology is impossible to avoid. 

 What’s crucial for parents, then, is knowing how and where to create boundaries. That goes for children of all ages, and of course, adults themselves. 

Here’s the story.

Dr. Bender: How does the brain make you feel a certain way, act a certain way, perceive the world a certain way?

Faith: This is Dr. Heidi Bender. A key concept to Dr. Bender’s work is neuroplasticity. In simple terms, a young brain has all sorts of potential – connections are firing every which way. But over time, the brain gets rid of, or prunes, connections it doesn’t use.

Dr. Bender: Typically, when neurons are, what is called pruned – meaning things that are extraneous and not used are kind of taken away – other areas are potentially strengthened, you can develop new neural connections that supplant what you had before and have some sort of neuroplasticity. And that’s something that’s so amazing about kids’ and adolescents’ brains is that they’re plastic and they can change.

Faith: For adults, our brains aren’t as plastic. We’ve already gone through a lot of pruning that strengthens how our brains work, how we think, and how we live. What many neuropsychologists, like Dr. Bender, are keen to understand now, is how screen time impacts the very impressionable, neuroplastic brains of kids and adolescents. Because kids are getting a lot of screen time.

Dr. Bender: 31% of children, ages zero to two are engaging with smartphones. And if you add in ages three to four, 29%. So roughly 50% of kiddos four years and younger are engaging with smartphones on a very regular basis. And then if you go to the tween age group, ages 8 to 12, they spend 4 to 6 hours a day watching screens or being on a smartphone. It’s an incredibly important time in a child’s brain development for them to be spending using a two-dimensional representation like a screen rather than engaging with people.

Faith: In really young ones, we do know that too much screen time can severely alter brain development.

Dr. Bender: Increased screen time can really reduce the integrity of brain structures that support early literacy in pre-kindergarten students. You can see delays in language acquisition variable attention, variable what we call emergent executive function skills, which are divided attention, sustained attention, multitasking. All of these, again, are these critical periods when you’re zero to five, when your brain is really learning to do what it can.

Faith: The effect of screen time on tweens and adolescents is less well understood. Which is why a recent study got Dr. Bender’s attention. It looked at kids’ phone habits – specifically how often they were checking in with social media.

Dr. Bender: This is a very critical time in brain development when the brain is especially sensitive to social feedback and specifically reward feedback. So basically the study is looking at, how does the frequency of an adolescent’s checking behaviors on social media, is that associated with changes in their brain development? Facebook and Instagram and Snapchat, is this really functionally and potentially even structurally impacting a child’s brain in a very specific way?

Faith: You know the feeling. Your post goes up and you wait for the responses to come in. Just the possibility of someone liking your post has you picking up your phone every two minutes. And this is where dopamine comes in. Dopamine is a chemical that carries messages in the reward centers of your brain.

Dr. Bender: There’s basically a dopamine dump with technology and social media use, and yes, of course, it is intrinsically very rewarding in addition to being extrinsically rewarding because, who doesn’t like to be liked and to get thumbs up and to hear that your hair looks fabulous and your dress is on point?

Faith: So, over the course of three years, the researchers used MRIs to get detailed pictures of what was going on inside the brains of these kids when they were experiencing those dopamine rush moments, triggered by social media.

Dr. Bender: What the study showed was that social media, these checking behaviors really are associated with changes in the brain’s sensitivity to social rewards and punishments.

Faith: And the more the kids in the study interacted with social media, the more sensitive they got to those interactions. That was the way their brains were changing. The question is what all this means. One possibility, and this is a familiar one, is that social media could become such an important part of a child’s world that it starts to take over.

Dr. Bender: It certainly could spiral into an elevated need for a child to be on social media. It’s completely reasonable that, could these kids be looking for that next flood in their brain that’s rewarding to come from social media instead of other things. You should be getting that feeling of being rewarded, that actual neurochemical reward in other ways – not just from social media.

Faith: One sign of this ‘spiral’ for parents to look out for? A behavior that will sound all too familiar to many of us.

Dr. Bender: If a child can’t take a social media or technology holiday and instead it causes a lot of anxiety. A lot of adults fall into this trap, right? If you don’t have your phone, you’re like, “Where’s my phone? Oh my goodness, what’s happening at work? I need to check!” When in fact you should just be enjoying the present and the here and now. So I think that’s something to really be mindful of for children as well.

Faith: Now, the results of the study aren’t conclusive proof that social media harms the adolescent brain. We know there’s a link to a reward reaction and increased sensitivity, but we need more research to fully understand the longterm effects of screen time and social media.

Dr. Bender: Is it necessarily a bad thing, quote unquote, to have a more sensitive brain activation to social cues. Well, maybe that’ll make you a kinder person. Maybe that’ll make you a more emotionally adept, nimble person. It doesn’t necessarily have to be a negative connotation down the road, but I don’t think we know.

Faith: So it’s not all doom and gloom, but there are some guidelines for the rest of us to follow about giving our kids time in front of a screen no matter what the activity is. And those guidelines, they’re pretty clear, especially for kids who are very young.

Dr. Bender: The American Academy of Pediatrics and the American Academy of Child and Adolescent Psychiatry, who are two of the biggest resources in terms of tracking this. They basically say no screen time at all from children until they’re about 18 or 24 months.

The exception of course, could be like if your parent is on vacation and this is the way to socialize with them, you chat with them, you chat with grandparents, but otherwise you should not be engaging in any sort of technology on a screen from 18 to 24 months. As the child gets a little bit older, a little bit more mature, let’s say two years, and up two to five, one hour of less per day is really the recommendation.

Faith: Dr. Bender says it’s worth it to be sure that their brains are developing, pruning and growing in a way that will help them thrive.

Dr. Bender: For children who are 6 and older it really is important to develop healthy habits with screen time and technology use. And that means limiting the time, limiting the content, making sure that’s not their only means of social engagement, not their only form of entertainment, that it’s being supplemented by interacting with parents, interacting with peers. Making sure it’s not the sole way that the child learns. I think these are all really important. And lastly, making sure the child’s not using technology right before bed because we know that there’s blue light emitting technology that can disrupt sleep patterns and sleep is so incredibly important for kiddos, we have to make sure their brains are well-rested.

Faith: Dr. Bender knows that all of this sounds pretty tricky. After all, she’s navigating these waters herself.

Dr. Bender: As my son ages and he gets to be a more digital kid, I definitely will have a very close eye on the content that he’s watching as I do now. But also make sure that if and when he does choose to go on social media platforms, I’d like to make sure I know who his, quote unquote, friends are. You really do have to be the child’s frontal lobes and make sure they’re exercising good judgment.

Faith: It’s about having conversations with your children about technology and social media — and even finding ways in which you can be involved and engage together.

Dr. Bender: I think there are a lot of different things that parents can do. One is to have a really open dialogue with their children about social media use, both the positives and the negatives. I think as a parent, if you only focus on the negative, your child will think you’re against them and you know, you couldn’t possibly understand — really talking about how it can be used as a positive tool, but like anything in moderation.

Also potentially finding a common interest with your child that is facilitated by technology and not hindered by it. You see all these parents making TikTok videos with their kiddos or looking as I do with my son on YouTube and we find different games we can play, or activities we can do. We look at the content together. If not, maybe even just coming up with a clear schedule for on screen time versus off screen time, making sure that it’s not a continuous all day affair. Making sure the child isn’t eating when engaged in tech activities because it could potentially be like a mindless eating.

Dr. Bender: I do think healthy boundaries are key and making sure that your child knows what they can and can’t do within those limitations. But of course, there are so many ways to use technology, again, in a very positive way, in a very constructive way, in a very developmentally appropriate way, by putting limits — boundaries — that you and your child could and should be discussing together.

Our many thanks to Dr. Bender.

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