Having a smartphone in the same room as you restricts your brainpower, even if the device is switched off, new research has found.

The study reveals that people struggle to complete simple tasks if their phone is in the same room as them.

The researchers say that smartphones act as a “brain drain” because part of our brain is always thinking about them.

This means that the mere presence of a smartphone limits brain power and function, even when people feel they're giving their full attention and focus to the task at hand.

“We see a linear trend that suggests that as the smartphone becomes more noticeable, participants' available cognitive capacity decreases,” said study lead author Dr Adrian Ward, a business expert at the University of Texas at Austin.

“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.”

The Austin team conducted experiments with nearly 800 smartphone users to measure, for the first time, how a nearby smartphone affects brain function.

In one experiment, the team asked participants to sit at a computer and take a series of tests that required full concentration in order to score well.

The tests were geared to measure participants' available cognitive capacity - the brain's ability to hold and process data.

Before beginning, participants were randomly instructed to place their smartphones either face down on the desk, in their pocket or bag, or in another room.

All participants were instructed to turn their phones to silent.

The researchers found that participants with their phones in another room significantly outperformed those with their phones on the desk.

They also slightly outperformed participants who had their phones in a pocket or bag.

In another experiment, researchers looked at participants' smartphone dependence - how strongly they felt they needed to have a smartphone in order to get through a typical day.

Participants performed the same series of computer-based tests as the first group and were randomly assigned to keep their smartphones either in sight on the desk face up, in a pocket or bag, or in another room.

In this experiment, some participants were also instructed to turn off their phones.

The researchers found that participants who were the most dependent on their smartphones performed worse compared with their less-dependent peers.

Dr Ward and his team found that it didn't matter whether a person's smartphone was turned on or off, or whether it was lying face up or face down on a desk.

Source: Daily Mail