Imagine this: you’re busy at work, writing one e-mail after another, when you decide that enough is enough and take a break from the task at hand. You can use this time to get catch-up with that colleague or walk yourself to the pantry for a hot cup of coffee. Instead, you whip out your phone and scroll through Instagram or play a game.

Our whole lives revolve around our smartphones. In fact, the first thing we do when we wake up is check our phones. Facebook FTW, after all! But everything in life comes at a price. And turns out that your dalliance with the gadget can cost you your mental ability—especially at work.

In an interesting experiment, the findings of which have been published in the Journal of Behavioral Addictions, over four hundred college undergraduates were asked to solve challenging sets of word puzzles.

Halfway through the task, some participants were allowed to take breaks using their cell phones, while others took breaks using paper or a computer. Some took no break at all.

The researchers, from Rutgers University in the US, found that the participants who took phone breaks experienced the highest levels of mental depletion and were among the least capable of solving the puzzles afterwards.

Their post-break efficiency and quickness was comparable to those who took no breaks at all.

Their number of word problems solved after the break was slightly better than those who took no break, but worse than all other participants.

Participants who took a break on their cell phones took 19% longer to do the rest of the task, and solved 22% fewer problems than those in the other break conditions combined.

“The act of reaching for your phone between tasks, or mid-task, is becoming more commonplace” said Terri Kurtzberg, an associate professor at Rutgers Business School.

“It is important to know the costs associated with reaching for this device during every spare minute. We assume it’s no different from any other break—but the phone may carry increasing levels of distraction that make it difficult to return focused attention to work tasks,” said Kurtzberg.

“Cell phones may have this affect because even just seeing your phone activates thoughts of checking messages, connecting with people, access to ever-refilling information and more, in ways that are different than how we use other screens like computers, and laptops,” she said.

We’re sure this is not the first study to point the obvious impact of mobile phones on your cognitive abilities and it won’t be the last. But we seriously do hope that you’ll put your smartphone down now and get back to work.