Listening and driving can be as dangerous as
drinking and driving, says a new study.
Scans of the brain showing the decrease in activation
when listening as well|
A car radio or a gossipy passenger can impair
driving in a similar way to drinking, so that a driver is more
likely to weave in and out of the borders of a lane on a motorway,
says the professor who led the new research.
Earlier work has shown that the ability of a driver
to focus on a task - what scientists refer to as selective attention
- depends on the availability of brain resources and much focus has
been placed on the safety of mobile phone use in the car, which
diverts and taxes these mental resources, so drivers can become
distracted, with tragic consequences.
Now, in the journal Brain Research, an American team
led by British born Prof Marcel Just, concludes that an even simpler
task - listening to someone speak while driving at the same time -
"reliably degraded driving performance".
As for how it compares with the effects of alcohol,
Prof Just says: "No quantitative comparison has been done
determining what blood alcohol level produces similar impairments to
listening on a cell phone."
Prof Just, Timothy Kellera and Jacquelyn Cynkara of
Carnegie Mellon University, Pittsburgh, hooked 29 participants - 14
women - up to an MRI brain imaging scanner while they were steering
a car along a winding virtual road. The participants not only
steered, but also listened to general knowledge sentences and
verified them as true or false using response buttons in their other
Reaction time and response accuracy were monitored
and performance on the simulated driving task was assessed.
The study shows that the addition of a listening
task decreased the brain activation associated with performing a
driving task by 37 per cent.
Using measures of performance on the simulator, the
researchers observed that driving while listening resulted in "much
poorer quality of driving". For example, the volunteers made more
errors in lane discipline, such as deviating from the middle and
hitting a guardrail.
Previous studies had suggested that driving and
listening used two different parts of the brain and could work
independently of each other, thus allowing the driver to
Driving and listening are two different tasks known
to draw on different brain networks - driving is perceptual-motor
and listening is cognitive - but the authors cite recent data that
indicate one can impact the other. This is backed by the "striking"
results of the new study, says Prof Just: it doesn't matter how
different the tasks are, the brain can only do so much at one
From listening or tuning in to a radio station, to
eating or drinking, to monitoring children or pets - all can be
distractions and can cause problems for the driver and others on the
road. "Drivers need to keep not only their hands on the wheel; they
also have to keep their brains on the road," says Prof