You probably don’t need a study to tell you that smartphones have made it harder to concentrate. But the Harvard Health Blog cites some interesting findings on that topic: “According to a new study, the mere presence of your smartphone, even if it isn’t ringing and even if you aren’t looking at it, can hurt your performance on certain cognitive tasks.”

College students were asked to complete a set of focus-intensive tasks. One group left their phones in a different room, one group held on to their phones, and one kept their phones out on their desks. The results:

Scores were highest when the smartphone was in the next room.

Scores were lowest when the phone was on the desk.

The impact of the smartphone’s location was most dramatic among those who reported being most reliant on their phones.

The effect of the smartphone was not altered by having the phone powered off (vs. set to silent mode) or placed face down (vs. face up).

Next time you’re trying to concentrate, ask if your phone is making it difficult. You might want to put it in another room!