Behind the Headlines

Wednesday October 21 2009

Mobile phone users were more likely to miss a unicycling clown

Research suggests that “people chatting on mobile phones are oblivious to their surroundings and can pose a risk to themselves and others,” The Daily Telegraph reported today.

This research found that people who used a mobile phone while walking were less likely to notice their surroundings than people using an MP3 player, walking with a companion or walking alone.

This study has important limitations, including the fact that the subjects were not randomised, and that the conclusions on the subjects’ walking behaviour were subjective judgements made by observers, potentially affecting their consistency and reliability.

However, despite these limitations, this study does highlight the fact that an individual’s attention is distracted when talking on a mobile phone. As previous studies have found, this is a hazard for both drivers and pedestrians.


Where did the story come from?

The research was carried out by Ira E. Hyman Jr. and colleagues from Western Washington University. It was published in the journal Applied Cognitive Psychology. No sources of funding were reported.


What kind of scientific study was this?

This experimental study investigated the effects of divided attention during walking. Several different distractions were compared, including mobile phones, MP3 players, walking with a companion or walking alone. Previous studies in driving simulators have shown that mobile phone use is associated with more inattention than when talking to another passenger or listening to music.

The researchers were particularly interested in the ability to notice new and distinctive stimuli, an absence of which the researchers term "inattentional blindness".

The researchers carried out two studies. In the first, trained observers watched people walking through the university centre while talking on a mobile phone, listening to an MP3 player, walking in a pair or walking alone without any electronic devices. Observations were collected for 196 individuals (94 males, 102 females; 180 classified as college-age, 11 as older and five as uncertain) who crossed in a diagonal line across a square without changing direction. Of these:

  • 43 were single individuals without electronics,
  • 47 were using a mobile,
  • 54 were using an MP3 player, and
  • 52 were part of a pair (for pairs, observers collected data on the closest individual).

The observers recorded:

  • the time taken to cross the square,
  • stopping,
  • direction change,
  • ‘weaving’, tripping or stumbling,
  • collision or near-collision with another, and
  • acknowledgement of other people.

They also noted factors including weather conditions, time of day and the day of the week that students were walking.

The second study further investigated the theory of inattentional blindness. This experiment was similar to the first, and involved 151 people:

  • 78 were single individuals without electronics,
  • 24 were mobile users,
  • 28 were using an MP3 player, and
  • 21 were part of a pair.

This time, the researchers arranged for a brightly coloured clown to ride a unicycle around the square. The participants were stopped after they had crossed the square and asked if they had seen anything unusual. Those who did not specifically mention the clown were then specifically asked if they had seen it.


What were the results of the study?

In the first study, the researchers found that mobile phone users and people in pairs walked more slowly than those listening to music or walking alone without electronic equipment. Phone users also changed directions more often, were less likely to acknowledge other people and ‘weaved’ more than others.

In the second study, mobile phone users were the least likely to say that they had noticed the unicycling clown than the other people walking. The researchers concluded that 75% of the phone users demonstrated inattentional blindness.


What interpretations did the researchers draw from these results?

The researchers conclude that mobile phones may cause ‘inattentional blindness’, even when used during a simple activity such as walking.


What does the NHS Knowledge Service make of this study?

This research found that people using a phone were more likely to demonstrate inattention to their surroundings than people using an MP3 player, walking with another or walking alone without distraction.

There are a few important limitations to this study that the authors point out themselves:

  • As this was not a trial, the people chose their walking condition themselves, so factors other than just the mobile phone use may have affected why they walked in the way that they did.
  • With the exception of the time it took to cross the square, other observations such as change in direction and weaving were quite subjective judgments made by the people watching.
  • There were relatively small numbers of people in each walking condition, which may affect the reliability of results.

The researchers say that previous studies have also found that talking on a mobile phone is more distracting than talking to a person next to you. In fact, the researchers claim that being in a pair actually improved the subjects’ performance in noticing their surroundings. This is borne out by their finding that those talking on mobiles changed direction more often, did not go in a straight line and failed to observe their surroundings.

Although this study has a number of methodological flaws, it nevertheless highlights the fact that an individual’s attention is distracted when they talk on a mobile phone. As previous studies have found, this is a hazard for both drivers and pedestrians.

Analysis by Bazian

Edited by NHS Choices

Links to the headlines

Mobile phone users cannot walk in straight line. The Daily Telegraph, October 21 2009

Would you notice this unicycling clown if he rode by? Three out of four people using a mobile phone didn't. Daily Mail, October 21 2009

Links to the science

Hyman Jr IE, Boss SM, Wise BM, et al. Did you see the unicycling clown? Inattentional blindness while walking and talking on a cell phone. Applied cognitive psychology 2009; Published online October 19


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