If you ever need a mental break during work or any mentally challenging task, using your cellphone during the downtime may do more harm than good.

A study out of Rutgers Business School suggests that once you put a mobile screen in front of your face, any work afterwards likely won't be as sharp as work done prior to the break.

The experiment, published in the Journal of Behavioral Addictions, used 414 Rutgers undergrads as participants. All were told to try to solve challenging sets of word puzzles.

Halfway through, participants were given a much simpler task — choose three items to buy within a specific budget — using either their cellphone, a laptop or a paper circular. Participants were told which method they had to utilize.

"What we found is that the people who picked up the phone and looked at it, even though they were doing exactly the same thing as other participants, ended up worse off for the second half of their task," said Terri Kurtzberg, co-author and associate professor of management and global business at Rutgers Business School.

In the end, those who used a phone took 19% longer to do the rest of the task, and solved 22% fewer problems than others. Some participants took no break at all.

Kurtzberg said a cellphone "may carry increasing levels of distraction" that make it difficult to return to the task at hand. The mind goes down "the rabbit hole," she said, now interested in checking messages and checking in on social media.

So what does this tell New Jerseyans? Kurtzberg said we'd all be better off finishing a task completely before picking up the smartphone and scrolling through messages and news feeds.

"If you need a break, do anything but look at your phone, is a more true conclusion based on this one study," she said.

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