AUSTIN — The power that a smartphone wields is even stronger than you’d think. A new study finds that simply having your phone within eyesight makes slows down your brain.

Researchers at the University of Texas at Austin recruited nearly 800 smartphone owners for a set of experiments, hoping to study how well phone users could complete tasks when they had their devices within a close proximity, even if they weren’t actively using them.

The first experiment conducted had participants complete a variety of computer-based tasks that measured available cognitive capacity— i.e., the ability to hold and process data. These tasks required full engagement on the part of the participant.

While all participants were told to place their phone on silent, different participants were randomly instructed to follow additional criteria: placing their phones on the desk face down, in their pocket or bag, or in another room altogether.

The researchers found that the participants who had their phone in a separate room fared the best on the tasks. The increase in performance was most substantial when compared to those who simply had their phone on their desk.

“We see a linear trend that suggests that as the smartphone becomes more noticeable, participants’ available cognitive capacity decreases,” says lead researcher Adrian Ward, an assistant professor of marketing, in a university press release. “Your conscious mind isn’t thinking about your smartphone, but that process — the process of requiring yourself to not think about something — uses up some of your limited cognitive resources. It’s a brain drain.”

A second experiment using the same tasks assigned in the first study examined how participants’ self-measured level of smartphone dependence— or how much one feels they need their phone to survive — affected their cognitive capacity.

Participants who were very dependent on their smartphone were found to perform worse on the tasks assigned, unless their phone was in another room.

In other words, having a phone in sight, regardless of whether it’s on or off, reduces one’s ability to focus, largely because part of their brain’s functioning power is diverted toward preventing themselves from using their device.

“It’s not that participants were distracted because they were getting notifications on their phones,” says Ward. “The mere presence of their smartphone was enough to reduce their cognitive capacity.”

The study’s findings were published in the Journal of the Association for Consumer Research.