When drivers' brains get a busy signal
HEALTH: Researchers find that motorists
talking on phones are more likely to react sluggishly to traffic signals or to
miss them.
By
Jane E. Allen, Times Staff Writer
We've heard the warnings. Whether
that cell phone conversation is a simple reminder to pick up milk or the
makings of a complex financial deal, when you're behind the wheel, it detracts
from the business at hand.
Now researchers are finding out exactly why. The brain can only do so much at
once, they say, and as a result, can't fully process the visual signals.
With the visual and auditory signals competing, the driver's ability to see and
react to what's ahead -- even when gazing directly at a car, sign or pedestrian
-- is diminished. This phenomenon of "inattention blindness," in
which the brain doesn't fully process what the eyes are taking in, helps
explain how cell phone conversations distract drivers and contribute to an
increasing number of accidents. There are more than 137 million
"Looking and seeing aren't one and the same," said University of Utah
psychologist David Strayer, who has spent five years
studying how cellular phone use interferes with driving. "Just because
your eyes are directed at something doesn't mean you're processing it. Seeing means paying attention. When you're not attending to
driving, you're more of a hazard."
Strayer and his colleagues previously found that
motorists talking on phones were more likely to react sluggishly to traffic
signals or to simply miss them. With a conversation diverting their attention
from the road, drivers are likelier to be tripped up by sudden events such as a
child darting into their path, another car slamming on its brakes or a light
change, Strayer said.
Many states have considered restricting cell phone use while driving.
The research appears in the March issue of the American Psychological Assn.'s
Journal of Experimental Psychology: Applied. Some of the findings also appear
in the February/March issue of Injury Insights, published by the nonprofit
National Safety Council.
The researchers drew their conclusions from several related experiments. They
placed 20 college students in a high-tech driving simulator and had them pass
numerous billboards while navigating a virtual road. Afterward, they tested the
subjects' recall of the billboards. They had 50% less recall of those
billboards they passed while talking on the phone than those they passed while
not using the phone.
In another experiment, they used video cameras and sophisticated instruments to
track the students' eye movements during virtual drives. Even when the
instruments confirmed that the participants were looking directly at objects
along the simulated road, those talking on the phone were less likely to
remember the objects.
The authors noted that although half the participants believed it was tougher
to talk and drive than just to drive, few thought their own driving was
impaired by casual cell phone conversations, even when the experiment showed
otherwise.
The problem lies with the distraction of a conversation, not of holding a
phone, experts say.
The
numbers:
·
Number of cell phone
subscribers in the
·
Estimated number of
cell phone owners who use their phone while driving: 85%
·
Estimated cell phone
use while behind the wheel: 60%
·
Estimated number of
drivers using a cell phone during any daytime moment: 500,000
·
Increased likelihood
of getting into an accident while driving and using a cell phone: 400%
Compiled
by June E. Allen