Many of us are in awe of the amazing opportunities for connectivity, information, and entertainment offered by our smartphones. But are we aware of the cognitive costs that come with frequent smartphone use?

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New research suggests that simply having your smartphone nearby can reduce brain power.

Researchers from the University of Texas at Austin set out to examine the effect that having one’s smartphone nearby can have on one’s ability to concentrate.

The team was led by Adrian Ward, an assistant professor at the McCombs School of Business at the University of Texas at Austin, and the findings were published in the Journal of the Association for Consumer Research.

As the authors of the new study explain, previous research had suggested that “the mere presence of personally relevant stimuli” can cause us to perform worse cognitively.

Prof. Ward and colleagues wanted to test this “brain drain” hypothesis in regard to smartphones. They wanted to see whether merely being in the presence of the device, without even using it, would make consumers less able to complete cognitive tasks.

They also wanted to see whether this potential effect would occur even when smartphone owners were otherwise able to successfully control their attention.

Prof. Ward and colleagues examined almost 800 smartphone owners. They asked the users to take part in two experiments designed to assess their ability to complete cognitive tasks while their smartphones were in the vicinity.

In one of the experiments, all participants had to put their smartphones on silent. They were then randomly assigned to one of the following scenarios:

  • the “high salience, ‘desk’ condition,” in which they had to keep their phones within reach and in sight
  • the “medium salience, ‘pocket/bag’ condition,” during which their phones were nearby but out of sight
  • the “low salience, ‘other room’ condition,” in which the device was in a separate room

Under each of these conditions, the participants were asked to complete a series of computerized tests created to test their ability to focus.

Scoring highly on the tests required perfect concentration. The tests were designed to evaluate the participants’ cognitive capacity on two dimensions: “available working memory capacity (WMC) and functional fluid intelligence (Gf).”

WMC refers to a person’s attentional resources, as well as his or her ability to use these resources to store and process new information. Gf describes a person’s ability to think about and solve new problems.

Overall, the experiment revealed that the sheer presence of a smartphone can affect cognitive capacity on both of these levels.

Participants who had their phones in a separate room performed much better than those who had their devices on the desk, and slightly better than those whose phones were in their pocket or bag.

“Even when people are successful at maintaining sustained attention – as when avoiding the temptation to check their phones – the mere presence of these devices reduces available cognitive capacity,” the authors write.

“We see a linear trend that suggests that as the smartphone becomes more noticeable, participants’ available cognitive capacity decreases.”

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.”

Prof. Adrian Ward

The second experiment replicated the tests, but included people who had also reported “smartphone dependence.” This was defined as how much people relied on their phones to carry out day-to-day tasks, and how they felt about not having their devices with them.

To assess smartphone dependence, Prof. Ward and team asked participants to provide answers to a 13-item questionnaire that included statements such as “I would have trouble getting through a normal day without my cellphone” or “Using my cellphone makes me feel happy.”

The experiment revealed that those who were the most dependent on their smartphones were the most affected by the brain drain phenomenon. For these individuals, the “cognitive costs are highest,” conclude the authors.

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