News of the Collegesummer2007

Ask a Prof: Behind the Wheel and on the Phone

Legislators have been taking aim at drivers who can’t stay off the phone. In New York, you can get a ticket if you’re caught driving and talking, unless you’re using a handless device. Legislation has been introduced in other states to ban everything from phoning without a handless device, to cell phone use by minors and school-bus drivers.

In his research on perception, cognition, and memory, psychology professor Dan Reisberg studies the effect of multitasking on the brain.

Reed: What happens when we drive and talk on a cell phone?

Reisberg: Think about your brain as being in some ways like an electrical generator with a certain amount of capacity that can be shared among various tasks. Ordinarily, driving doesn't take much capacity, and so a lot is left over for other chores. The same is true of conversation. But sometimes, the demands of either one can spike—because you’re doing a high-speed merge or the conversation is getting intense—and then you don’t have enough capacity for both, and something has to suffer.

There are now a number of studies showing that if you’re engaged in phone conversation while driving, you’re slower in responding to traffic signals, less likely to notice things like warning signs, slower in hitting the brakes when you need to, and so on.

Is the conversation the problem, or the phone you’re having the conversation on?

Here the data are impressive: the problem really is the conversation itself, and, in many studies, the dangers seem identical for hand-held cell phones or hands-free cell phones. The idea that the road to safety is to ban just the hand-held cell phones is bogus.

But we have conversations with passengers while we’re driving all the time. Isn't that just as dangerous as conversing on the phone?

When someone else is in the car, they can see the road situation, so they cooperatively slow the conversation down when the driving gets tough. Likewise, they can see you, so they slow the conversation when your body language signals that you need to focus on your driving. As a result, conversations with a passenger aren't problematic; instead, the danger here really is tied to the use of a phone.

Young drivers reportedly text-message with both hands while driving. Should they be banned from using their phones behind the wheel?

Certainly, sending text while you’re driving (which means you need to take your hands off the wheel and your eyes off the road) is madness. But, on the other hand, it’s possible that cell phone conversations may be less dangerous for young drivers. My sons have grown up with cell phones and they've developed systems of multitasking that older drivers never developed. They don’t have any more capacity than an older driver does, but they have different priorities. For example, if the demand for attention spikes up, you or I might try to keep the conversation going, and make our driving worse as a result. My sense (with no data yet to confirm this) is that younger drivers have more sensible priorities and have simply learned, when there’s a conflict between talking and driving, just to be rude to whomever they’re talking to. Impolite, maybe, but surely a better idea.