You’ve heard it before: your smartphone is bad for you. People get addicted, it harms your personal life and gets in the way when it matters most. But a new study found that your smartphone isn’t just harming your personal life — it might be making you less intelligent.

Research published in the journal Applied Cognitive Psychology found that using your smartphone can lead to decreased suctions when it comes to analyzing information. The study, which included two control experiments, took a look at the lingering effects of smartphone technology and use on brain function.

In total, three studies were performed to examine smartphones’ impact on cognition. The experiments had participants install tracking software on their devices in order for researchers to be able to calculate screen time.

That’s when researchers discovered that people are spending nearly a fifth of their day staring at their phones.

“Using tracking apps, we found that people use their smartphones for about five-and-a-half hours a day—that is about a third of people’s waking hours! One of our lab assistants was surprised when she found out how much she uses her smartphone — more hours than would be expected of a full-time job,” said Peter Frost said, a professor of psychology at Southern New Hampshire University.

In the first study, researchers focused on 105 undergraduate students and found that their smartphone use was linked to lower performance in social problems solving. Another study was a week-long look at 50 students who were randomly assigned to two groups, one allowing just two hours per day of phone use while the other encouraged at least 5 hours a day.

The participants who were instructed to interact with their phones for over 5 hours daily had less ability to analyze and interpret compared to the group who were allocated just two hours per day, as per the Cornell Critical Thinking Test.

The final study examined 50 undergrads for nearly a month using a similar model to the second study, which confirmed to researchers that those who used their phones for more than five hours daily had diminished cognitive abilities, but that effect wore off, meaning it was only temporary.

“In a nutshell, we found that very few aspects of cognition were affected in the long run,” Frost said. “We did find that the ability to extract the deeper meaning of information was influenced by heavy, daily smartphone use, but only for a limited amount of time (for about no more than a month after increased use).”

This article originally appeared on The Ladders.

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