Preteens using increasing amounts of social media perform poorer in reading, vocabulary and memory tests in early adolescence compared with those who use no or little social media.
That's according to a new study that suggests a link between social media use and poorer cognition in teens. The findings are published in JAMA.
"This is a really exciting study," says psychologist Mitch Prinstein at the University of North Carolina at Chapel Hill, who wasn't involved in the new research.
"It confirms a lot of what we have been hearing about from schools all across the country, which is that kids are just having a really hard time focusing on being able to learn as well as they used to, because of the ways in which social media has changed their ability to process information, perhaps."
While most previous research has focused on the impact of social media use on kids' mental health, "it's critical to understand how social media use during school hours specifically affects learning, especially as so many schools are considering phone bans right now," says study author and pediatrician Jason Nagata of the University of California, San Francisco.
A look at reading and memory
To understand that, Nagata and his colleagues used data from one of the largest ongoing studies on adolescents, called the Adolescent Brain Cognitive Development (ABCD) Study. Scientists have been following thousands of preteens as they go through adolescence to understand the development of their brains.
The ongoing study has been surveying kids about their social media use every year and giving them a range of tests for learning and memory every other year. Nagata and his colleagues used data on over 6,000 children, ages 9 to 10, as scientists followed them through early adolescence.
They classified the kids into three groups based on their evolving patterns of social media use. The biggest group, consisting of about 58% of the kids, used little or no social media over the next few years. The second-largest group, about 37% of kids, started out with low-level use of social media, but by the time they turned 13, they were spending about an hour each day on social media.
The remaining 6% of kids — called the "high increasing social media group" — were spending about three or more hours a day by age 13.
"The dosage effect"
All the groups were given a range of tests to measure their cognitive functioning at the start of the study and in early adolescence. For example, the oral reading recognition test examined their reading and vocabulary skills. Another test, called the picture vocabulary test, had them match the right pictures to words they heard.
"What was notable actually to me and perhaps surprising was that even the low [increasing] social media users, so those who had about one hour a day by age 13, did perform on average 1 to 2 points lower on the reading and memory tasks compared to the non-social media users," says Nagata.
And the high increasing group performed up to 4 to 5 points lower than the non-social media users.
"So those who had the highest social media use have lower scores," notes Nagata, "but even the low users had smaller differences in their cognitive scores."
"That really speaks to the dosage effect of these [apps]," says psychologist Sheri Madigan at the University of Calgary, who wrote an accompanying editorial for the study. "It's problematic at really high uses, but it's also problematic at even in small doses."
While a difference of a few points in test scores may seem insignificant, "it's important to understand that kids are a moving target," explains Prinstein, who is also chief of psychology strategy and integration at the American Psychological Association.
"Even a slight change in what they look like after a short period of time means that they're kind of now pointed on a trajectory that is different from others. That means that two, three, five years from now, we might be talking about some very significant gaps between kids who might have been heavy users or not as heavy users."
And other recent research shows that hours on social media increase later in adolescence, notes Nagata. "We would expect that when they hit age 15, 16, 17, their use will be much higher," which might lead to even larger gaps in cognition and learning in later years, he adds.
In earlier studies, Nagata's team has used the same data from the ABCD Study and found other disturbing trends among underage social media users.
They found that a majority of kids — nearly two-thirds — start using social media before they turn 13, with the average user having three social media accounts.
They also found high levels of addiction-like symptoms with smartphones among 10-to-14-year-olds.
"Half the kids who had smartphones said that they lose track of how much time they're using their phone," says Nagata. "A quarter who are using social media say they use social media to forget about their problems. And 11% say that social media use has negatively affected their schoolwork."
An important time for brain development
Adolescence is a critical period for brain development, notes Prinstein, when the brain is fine-tuning its architecture based on experiences.
"After the first year of life, the adolescent period is the time where we see the most growth and the biggest reorganization of the brain in our lifetimes," he says.
In a recent study, Prinstein and his colleagues found that teens who are heavy social media users have brains that are more attuned to an existence on social media, with its "rapid, constant feedback," says Prinstein. "What we're finding is that kids become hypersensitive to the kinds of likes, comments, feedback and rewards they might get from peers."
Those findings help explain the results of the new studies, he adds. "It makes perfect sense that if their brain is growing to be optimized for social media activities, it might not be optimized for other things they need to do, like we saw in the [new] study."
The new study also "gives us good-enough evidence that we really need to create some policies that are really specific around creating age limits, for example, on social media apps," says Madigan.
Denmark announced last week that it plans to enforce a social media ban for users under age 15, she notes. Australia is requiring social media companies to "take reasonable steps to prevent Australians under the age of 16 from creating or keeping an account" starting December 2025.
Madigan hopes other countries will take note. "I think that we'll see a trickle effect on that. That's going to be really beneficial for kids."
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