Keeping your smartphone nearby may not be so smart

Robert H. Shmerling, MD

Senior Faculty Editor, Harvard Health Publishing

Follow me on Twitter @RobShmerling

Imagine you were asked to complete a series of math problems, ones just hard enough to require your attention and focus, but nothing you couldn’t handle. Now, imagine you were intermittently interrupted from these math problems and asked to remember a random list of letters. This might be even tougher.

It’s reasonable to assume your performance on these tasks might be impaired by distractions such as loud noise or nearby conversation. But what about the smartphone in your pocket or purse? 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.

What’s the evidence?

Researchers publishing in the April 2017 edition of the Journal of the Association for Consumer Research describe a series of experiments in which 520 college students performed tasks requiring focus, attention, and novel problem-solving skills. Some were asked to leave their smartphones in another room. Others were allowed to keep them where they usually do (such as in their pocket or purse). A third group was asked to set their phones on the desk next to them.

Remarkably, performance on the tasks of attention and problem-solving varied depending on the location of the smartphone:

  • 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).

These findings suggest that having a smartphone nearby can be distracting even when it’s not in use. It may be that the power, convenience, and connectivity provided by smartphones come at a “cognitive cost.” The authors of this new study call it “brain drain.” And it may be more common — and more profound — than we realize.

Now what?

While this new study suggests an unexpected downside to smartphones, it also suggests a potential solution. We might use our intellectual firepower more effectively if we spent some time with our phones well away from us. If it’s always on your person or quickly within reach, you may be distracted by its presence without even realizing it. And that’s in addition to the more obvious distraction of a phone ringing or alerting us to emails or text messages.

It’s possible we’d all be smarter taking a break from our smartphones. This new study suggests it’s worth a try.

Related Information: A Guide to Cognitive Fitness


  1. Jane

    It’s interesting how many of us (not everybody) are convinced that “this may be true for some other people but not for ME.”

  2. Morley Markson

    it’s not just the iphone, it’s the constant barrage of active problem-solving advertisements like the one above, that take me away from my work…. yet I can glean, in a moment, the essence of your research, your statement, and am reassured that distancing myself from constant availabilily to to a universe-full of good suggestions and necessary ideas, like yours. Thank you. Now, isn’t that ironic? The solution, of course, and as always, is balance, scheduling. End of this time slot. End of this reply.

  3. Hérold Jean-François

    I think it’s not only students, smart phone’s addiction make everyone lost a lot of time more even than we realize. This study is acurate and we must pay attention to be more productive in our works using our cellular phone in a rational way.
    The entire world would be more competitive if professionals were less addict to cellular phone and his distractive power.


    Our cognitive development shrink gradually as long as we are in high touch with the high tech
    The more we rely on the high tech the less we depend on the high touch
    Unfortunately the smart technology destroy our brain as well as our nerves cells and not only that but we are becoming addicted and slaves to it
    in the past decades we were independent of all this , nowadays it’s becoming essential in our daily life and we all depend on it
    The biggest question remains unclear whether to stop relying on using smart technology and use our smart biological brain or to depend on someone else’s….. that cause brain damage

  5. taosword

    I would be willing to guess that the frequency that the subjects usually text, answer texts, call or answer calls, or play games will distract concentration with the more frequent user. The brain is like cyclical and use to this use of a cell phone reoccuring at certain intervals setting up an unconscious expectation that distracts the subject.

  6. ron beAGLE

    Conclusion; college students who have no responsibilities
    that involve communications from others on a smart phone
    should leave them alone while doing tasks as long as the reward from doing the task outweighs the the benefit of receiving
    information that might come in on their cell phone.

  7. RS Mallory

    EMF’s are all over the place in our Electronic Age. I use BioZen anti electro smog stickers on my phones, blue tooth, even car (it has a computer), TV, Stereo and IF I had a microwave I would put one there too 😉 Also great for electrical outlets if you’ve got little kids, pets or grandkids close to floor level 😉 is where I get mine.

  8. SRCT

    I wonder if this is equally true for all generations? The study focused on college students; do older adults and elementary school students have the problem to the same degree?

  9. Priscilla

    Theirs a time for everything.. key is common sense.Priscilla

  10. Pat

    It’s not just concentration that is being affected by these type of devices.
    It is our health also. They emit radiation which is especially risky when it is pressed up against your head. Children are especially vulnerable as their skulls are still forming and soft. Radiation passes more easily into their brains. In some countries, children are not allowed to own or use a device such as a smartphone because of these concerns.

    More information can be found on line about this issue. There is a list of which phones emit the most radiation. IPads also fall into this category .

  11. Chris

    According to my studies as early as 2004, cell phones can be dangerous to our health. While a periodic interference might not be harmful, the electro-magnetic radiation is definitely harmful despite what the Telecom industry says. As an example, it would be suicidal for me to keep my cell phone within 20 inches from my Pacemaker because it would disturb
    the Pacemaker’s signals.

  12. Faripour Forouhar, M.D.

    I am reading the comments and am compelled to comment that most people underestimate the unconscious impact of the psychological energy drain that electronic media instigates; among other harms such as attention deficit to real world.
    It has also come to light that designer of these media in particular cell phones, very methodically use all psychological knowledge available to make the cell phones as “addictive” as possible, so that people keep “going for them”.

  13. Mai Lanh

    I agree with this findings.
    Smart phone make us no focus!

    • Gurpal kingra

      Too much reliance on cell phone or any computer makes us less likely to use our god given ability to think and focus on subject at hand.

  14. William

    Perhaps written by a boss, teacher, or someone else in a disproportionate amount of power who wants to confiscate smartphones and possibly the data inside?

  15. Nancy

    Seems like they were just distracted knowing the answers to the questions were only within an arm’s reach.

    • Paul

      That was exactly my thought, Nancy. They’re thinking, “if I could just use this phone– this one right next to me–, I could solve this problem so much faster! And I could be confident that the answer was right. ” THAT is what’s affecting their functioning.

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