Initial Study Finds Cell Phones Distracting, Validates Experimental Set-up

Leave it to a couple of New Yorkers to inform the world about the dangers of trying to cross a busy street while talking on a cell phone. Beckman Institute researchers Art Kramer and Mark Neider, both native New Yorkers, and their collaborators have just published the first paper in a research line that is investigating pedestrian distraction in a completely original way.

Neider is a postdoctoral research associate at Beckman and lead author of the paper, which reports on dual task performance involving talking on a cell phone or listening to music on an iPod while test subjects try to cross a virtual reality street. The researchers said it is the first study of its kind to use an experimental approach to investigate pedestrian distraction and the first to employ virtual reality (VR) technology to study the topic.

The paper reports that talking on a cell was in fact a distraction while trying to cross the street but that listening to an iPod was not. So, what should people take away from this first paper on the subject?

“They should be aware that their ability to do certain tasks can be impaired when they are using these types of devices,” Neider said. “I’m not going to sit here and tell people not to talk on their cell phones. But be aware and act accordingly. If you are talking on a cell phone and about to cross a street, maybe tell somebody to hold on for a second.”

Neider said this initial paper has laid the groundwork to expand research on the topic of pedestrian distraction and related cognitive issues.

“I think this is a good start,” Neider said. “We have taken the dual task paradigm, which is a classic paradigm, and moved it along here to an ecologically valid environment. Getting at the underlying theoretical mechanisms that are in play, what’s impaired and where that impairment stems from, are open questions and ones that we are looking at now.”

The research line has its origins in a meeting between Kramer, Neider, and fellow Beckman researcher Jason McCarley. McCarley is a co-author of the paper, as are Hank Kaczmarski and James Crowell of Beckman’s Illinois Simulator Laboratory (ISL). Kaczmarski and Crowell created the experiment’s virtual reality environment using the ISL’s CAVE immersive VR technology and a modified treadmill.

This first study was done with college students, who were grouped into three categories for performing the street crossing task: no distraction, listening to music on an iPod, and talking on a cell phone. While the results showed that talking on a cell phone is a distraction while crossing a street, one result that surprised the investigators was that talking on a cell phone did not cause pedestrian-vehicle collisions.

Both Kramer and Neider caution that that finding probably has to do with the experiment’s parameters. There was no motivation in this initial study for test subjects to cross the intersection quickly.

“Whereas in the real world, people are often in a rush,” Neider said. “They run around like ants marching in New York. Everybody has to get somewhere and they have to be there five minutes ago. It’s possible that when you are under this sort of pressure you are more likely to take higher risks in that situation and when you talking on a cell phone you may have problems.”  

“We left it open-ended; we left a lot of time for people to cross the street. In retrospect maybe we shouldn’t have done that,” Kramer said. “When we do future experiments, one thing we’ll do is give people incentives to cross quickly – just as they have incentives now: they don’t want to miss a class, they have to get to a business meeting, or they have to go to a job interview.”

Despite the fact this experiment didn’t cause distracted students to have collisions with virtual automobiles, Kramer said that result shouldn’t be misconstrued by the general public.

“When you talk to somebody in the street and ask ‘could somebody listen to an iPod or talk on a hands-free cell phone when they are walking’ they say, ‘Walking? We’ve been walking our whole lives. Sure, it’s not a problem,’” Kramer said. “But it’s not the walking necessarily; it’s actually walking and paying attention to relevant things like automobiles or bicycles.

“That’s why we began this, as a way to look at yet another automatic behavior that we assume is impenetrable. But, with respect to distraction, it is not impenetrable because, when this behavior is in the context of the real world, you really do have to pay attention to what’s going on. We are not, evidently, experts on paying attention to vehicles when we are crossing the street.”

Issues such as the mechanisms underlying our dual and multi-tasking behaviors provide great scientific fodder for future projects. Neider was pleased that this first experiment laid a solid foundation for further study on a variety of cognitive issues involving pedestrian distraction.

“I think this provided us with a good idea of what’s happening and now the idea is to look closer at each individual piece to see where this impairment on cell phone comes from,” Neider said. “Is it comprehension, or is it production, and what are the effects on attention? Or is it encoding, is it an inability to detect changes, some sort of change blindness. There are lots of possibilities. It will take many experiments to tease apart, but that is the direction with this. But we’ve validated the task in this first pass and that is no small feat considering the step up to the more realistic environment.”

Kramer said future studies include looking at the nature of the dual task interaction involved in crossing a street while distracted. He said the data showing listening to an iPod was not distracting might have more to do with the fact subjects were listening to music rather than, for example, a podcast on a scientific topic.

“That might be more analogous to comprehension and speech where you want to remember something or pick up some information.” Kramer said. “We chose the nature of the iPod task because that’s what students do, they listen to music. And this is music they have probably listened to a hundred times. If they miss something, who cares. In terms of a podcast, I usually care because I don’t listen to them more than once.

“I wouldn’t suggest that iPods in and of themselves are safe,” Kramer added. “It’s what we had people doing on the iPods. So the nature of the mechanisms that underlie this interaction is important. The kinds of changes that happen – and we were able to look at eye movements, and head movements, and crossing time – were important but I think we need to push the situation, make it a bit more realistic.”

While the science drives this project, several on-campus accidents involving vehicles and students, including one that was fatal, were also a factor in the decision to investigate this topic.

“Another impetus for these studies was the young people getting run over, often when they had the earbuds in or were talking on their phone,” Kramer said.

Future studies should give more clarity to the topic of pedestrian distraction.

“When people were talking on a cell phone it took them longer to begin their street crossing than when they weren’t on a cell phone,” Neider said. “One explanation is that they are being more conservative. They know they are talking on a cell phone, they know that they are impaired, so they are taking more time and looking more carefully.

“The other possibility is that they are just missing safe crossing opportunities when they arise that they would have recognized if they weren’t under dual task impairment. We can’t parse those two things out from the data that we have, or the mechanisms that are underlying these things. What about attention is being impaired? It’s the theoretical questions we’ll be going after now.”