ASMA KHALID, HOST:
Parents are constantly being told they have to limit how much junk food their kids can eat or how long they allow their children to watch cartoons. And I will say for a lot of moms and dads, yours here included, that can feel impossible. Neuroscientists say they know why it's such a struggle. For our series called Living Better, NPR's Michaeleen Doucleff found out what's happening in a kid's brain that drives this overconsumption.
MICHAELEEN DOUCLEFF, BYLINE: Whether it's spending hours scrolling on social media or eating copious amounts of sugary junk food, these activities tap into ancient neural circuits and cause a surge in a molecule inside a child's brain called dopamine. Anne-Noel Samaha is a neuroscientist at the University of Montreal. She says these circuits and dopamine are critical to keeping your child alive.
ANNE-NOEL SAMAHA: These mechanisms evolved in our brain to draw us to things that are essential to our survival - you know, water, safety, sex, food.
DOUCLEFF: In other words, there's something in the sugary foods and the flickering screens that releases dopamine and tricks the brain into thinking they're essential. This molecule, she says, has gotten a lot of attention recently, but there's a big misconception about it.
SAMAHA: In popular media, there's this idea that dopamine equates pleasure.
DOUCLEFF: That these bursts of dopamine make you love whatever you're doing. Journalists have even called dopamine the molecule of happiness. But Samaha says...
SAMAHA: There's actually little convincing data in science that that's what dopamine does. And there's, in fact, a lot of data to refute the idea that dopamine is mediating pleasure.
DOUCLEFF: Instead, research now shows that dopamine generates another emotion - desire.
SAMAHA: Dopamine makes you want things.
DOUCLEFF: Whatever is triggering a big spike in dopamine pulls your attention to it.
SAMAHA: Your brain tells you something important is happening. So you should stay here, stay close to this thing because this is important to you. That's what dopamine does.
DOUCLEFF: And here's the surprising part. Whatever dopamine makes you want, you might not actually like it, especially over time. In fact, studies show that people can end up not liking, even hating, the activity they're doing.
SAMAHA: If you talk to people who spend a lot of time shopping online or going through social media, they don't necessarily feel good after doing it. There's a lot of evidence that it's quite the opposite.
DOUCLEFF: So let's look at what this means for kids. My daughter is 7, and she was getting in the habit of watching cartoons every night. And while her eyes fixate on the Technicolor images, dopamine bursts in her brain not once, but repeatedly, and that keeps her wanting to watch. Then I come in and say, time's up; time to go to bed, and take the screen away from her abruptly. But the dopamine doesn't go away immediately.
SAMAHA: The dopamine levels are still high. And what does dopamine do? Dopamine tells you that something important is happening, and there's a need somewhere that you have to answer.
DOUCLEFF: In other words, I'm ripping this important thing away from my daughter that she may feel is critical to her survival. Samaha says this can be incredibly frustrating for a kid, even enraging. And so she fights me.
EMILY CHERKIN: It's not you versus your child. It is you versus a hijacked neural pathway. It is the dopamine you're fighting, and it's not a fair fight.
DOUCLEFF: That's Emily Cherkin. She was a middle school teacher for over a decade and now is a screen consultant. She says this can be hard for even adults to handle. So she tells parents, wait as long as possible before bringing new devices, new apps, new ways of watching videos, even new types of junk food into your home.
CHERKIN: I talk to hundreds of parents, and they - not one has ever said to me, I wish I gave my kid a phone earlier, or I wish I'd given them social media access at a younger age. Never.
DOUCLEFF: And for the activities that kids are already entangled with - Dr. Anna Lembke is a psychiatrist at Stanford University - she says parents can figure out if the activity or snacking is healthy and unlikely to become a problem. That's true when...
ANNA LEMBKE: The activities that we feel good doing it and then afterwards we feel even better, that's really the key. That means that we're getting a healthy source of dopamine.
DOUCLEFF: But the things that make you feel worse afterwards, those are concerning. Lembke says parents should be very careful with those activities and foods.
LEMBKE: We need to limit quantity and frequency of use.
DOUCLEFF: So how on earth do parents do that? Lembke says it's tough at first. Kids get cranky. But there are a few things you can do to make it easier. For starters...
LEMBKE: Create microenvironments.
DOUCLEFF: Places in the home and times during the day where the child cannot see or access the device or food. For example, my family stopped bringing screens in the car. We removed them from all but one room in the house, and we started camping once a month - no screens.
LEMBKE: When we know we can't go on, the craving goes away.
DOUCLEFF: And for sugary foods, we enjoy them at parties or ice cream parlors. And if my daughter does want a treat at home, she bakes it. Finally, try a habit makeover. Instead of cutting out an activity, look for a version that's more purposeful.
YEVGENIA KOZOROVITSKIY: We're creatures of habit in a really fundamental way, so we cannot get rid of all of our habits. We can just seek to build habits that are a little bit, you know, healthier than other habits.
DOUCLEFF: That's Yevgenia Kozorovitskiy. She's a neurobiologist at Northwestern University. She has two tween boys, and she encourages them to play this adventure video game that requires many cognitive skills.
KOZOROVITSKIY: Advanced social and language skills - somehow, you know, I don't feel the same way about them playing that game.
DOUCLEFF: I tried this strategy with my daughter. We switched the cartoons for a language-learning game, and guess what happened? After two weeks, she lost interest in that program and the screen completely.
Michaeleen Doucleff, NPR News.
(SOUNDBITE OF LYMBYC SYSTYM'S "GEOMETER") Transcript provided by NPR, Copyright NPR.
