New US research has found that just having your smartphone nearby reduces cognitive capacity and the ability to complete tasks -- even when it's switched off.
Carried out by researchers from the McCombs School of Business at The University of Texas at Austin, the study set out to try to measure for the first time how well people can complete tasks when they have their smartphones nearby, but are not using them.
The team recruited nearly 800 smartphone users, who in the first part of the study were asked to sit at a computer and complete a series of tests that required full concentration in order to attain a good score.
The tests were designed to measure participants' available cognitive capacity -- the brain's ability to hold and process data at any given time.
Participants were randomly instructed to either place their smartphone either face down on the desk, in their pocket, in their bag, or in another room.
Regardless of where their phone was, all participants were instructed to turn their phones to silent.