Just How ‘Blind’ Are You When Talking on a Cell Phone?

cell-phone-driving_smallEveryday in the news we see stories decrying the use of cell phones while driving.  Research reports aplenty have been released estimating the percentage of one’s attention siphoned by mobile jabber and how little is left to focus on the highway. 

This is great and I’m glad the discussion is happening, but it might be useful to ask whether cell phone use in other (non-driving) venues has a similar effect on attention. What better way to make the point that cell phone use is dangerous when driving than showing its effect on someone doing something not nearly as focus intensive — like walking, for instance.

That’s exactly what the authors of a new study published in the journal Applied Cognitive Psychology wanted to do. Researchers examined the effects of divided attention when people are either (1) walking while talking on a cell phone, (2) walking and listening to an MP3 player, (3) walking without any electronics, or (4) walking in a pair. 

The measure of how much attention is diverted during any of these activities is called “inattentional blindness” — not ‘seeing’ what’s right in front of you, or around you, due to a distracting influence.  If you’ve ever watched the YouTube video of the gorilla walking through the crowd of people passing around a ball, then you’ve seen an example of inattentional blindness (here’s a great paper on the effect downloadable as a PDF). 

For the first experiment of the study, trained observers were positioned at corners of a large, well-traveled square of a university campus.  Data was collected on 317 individuals, ages 18 and older, with a roughly equal breakdown between men and women.  The breakdown between the four conditions (with MP3, with cell phone, etc) was also roughly equal.  Observers measured several outcomes for each individual, including the time it took to cross the square; if the individual stopped while crossing; the number of direction changes the individual made; how much they weaved, tripped or stumbled; and if someone was involved in a collision or near-collision with another walker.

The results:  for people talking on cell phones, every measure with the exception of two (length of time and stopping) was significantly higher than the other conditions.  Cell phones users changed direction seven times as much as someone without a cell phone (29.8% vs 4.7%), three times as much as someone with an MP3 player (vs 11%), and weaved around others significantly more than the other conditions (though, interestingly, the MP3 users weaved the least of all conditions). 

People on phones also acknowledged others only 2.1%  of the time (vs 11.6% for someone not on a phone), and collided or nearly collided with others 4.3% of the time (vs 0% for walking alone or in a pair, and 1.9% when using an MP3 player).

The slowest people, who also stopped the most, were walking in pairs.  In fact, next to the other conditions walking in pairs was the only one that came anywhere close to using a cell phone across the range of measures.

The next experiment replicated the first, but only one measure was tracked: whether or not walkers saw a clown unicycling across the square.  And this was an obnoxiously costumed clown, complete with huge red shoes, gigantic red nose and a bright purple and yellow outfit.  Interviewers approached people who had just walked through the square and asked them two questions: (1) did you just see anything unusual?, and (2) did you see the clown?

The results:  When asked if they saw anything unusual, 8.3% of cell phone users said yes, compared to between 32 and 57% of those walking without electronic devices, with an MP3 player, or in pairs.  When asked if they saw the clown, 25% of cell phone users said yes compared to 51%, 60% and 71.4% of the other conditions, respectively.  In effect, 75% of the cell phone users experienced inattentional blindness.  (The discrepancy between the 8.3% and the 25% might be because the clown didn’t register as something “unusual” — this is, after all, a university campus.)

So, coming back around to the original point — if using a cell phone impairs attention as drastically as this study shows for people just walking, could it by any stretch of the imagination be a good idea to use one while driving? 

One caveat to that concluding question should be mentioned: As noted in the results, people walking in pairs–most likely talking to each other–were next in line for inattentional blindness. This jibes with research (discussed in this TIME article) indicating that talking to someone in your car while driving is significantly distracting–perhaps not quite as much as chatting on a cell phone, but in the neighborhood.  Auditory cues, whether from a phone or from the person next to you, divert attention. The problem with cell phones, however, is that a user lacks the other set of eyes his co-chatter has to offer, which could very well be the difference between being in an accident or getting home safely.

Hyman, I., Boss, S., Wise, B., McKenzie, K., & Caggiano, J. (2009). Did you see the unicycling clown? Inattentional blindness while walking and talking on a cell phone Applied Cognitive PsychologyDOI: 10.1002/acp.1638


Filed under About Perception, About Research

10 responses to “Just How ‘Blind’ Are You When Talking on a Cell Phone?

  1. Jim Battle

    I think there are a couple of factors which making talking on a cell phone while driving significantly more attention consuming than having a conversation with someone else in the car.

    First, as anybody who has used a cell phone knows, the call quality often stinks, and at best is grossly inferior to speaking with someone in person. It takes a lot more “CPU cycles” to follow what the person on the other end is saying.

    Second, there is a social expectation that when you speak with someone on the phone, you are paying attention to them. There is much the same pressure when speaking with someone in the car, but since the passenger has a shared context with the driver, at moments of increased need for driving attention, the driver is free to attend to the road. For instance, if a tricky traffic situation arises, the driver can pause the conversation and wait for it to resolve, or even for something as simple as doing a lane check, the driver can simply do it and return to the flow of conversation without worry.

  2. David Harmon

    The article is reasonable and unsurprising, but the example YouTube video you give is a bit unfair — it’s not just a matter of “concentrating on something else”. You’re specifically directed to attend to the players in white. The *other* players, the ones you’ve implicitly been told to filter out, are in black. The costumed intruder is in black. (And is also the 9th figure on the court, thus pushing our “seven, plus or minus two” mental registers.)

  3. I think that one of the reasons we’re “blinder” when talking on cell phones is because we are also visualizing the person on the other end of the line as well as a topic of conversation. Still, I find it odd that we focus on phone users and not, say, taxi drivers or police officers using two-way radio.

    I do sometimes use the phone well driving, but not to yack, and with extra space around me and heightened alertness. “Mary? We’re in stop-and-go traffic and will be another half an hour. See you then. Bye.”

  4. scottw

    > The problem with cell phones, however, is that a user lacks
    > the other set of eyes his co-chatter has to offer, which
    > could very well be the difference between being in an
    > accident or getting home safely.

    I think the experiment had support for this. If I
    understand your sentence, the highest percentage of people
    who said yes to “did you see a clown?” were the people
    walking in pairs.

  5. But who was the clown and were they credited as that in the paper? “Dr A drafted the paper, Dr B designed the experiment, Dr C was the clown” – could be a career killer.

  6. Really like your blog. Great info Dave

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  8. It’s hard to come by knowledgeable people in this particular subject, however, you seem like you know what you’re talking about! Thanks

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