The message is finally getting out
there that smart phones cause real problems while driving. Texting while on the road is extremely
dangerous, because it requires the driver to look away from the road and also
soaks up precious mental resources. Even
talking on the cell phone can be dangerous.
But, if cell phones are so
obviously dangerous, then why do we continue to talk on the phone and
drive? Why do so many people think that
they are actually pretty good at multitasking while they drive?
This question was addressed in an
interesting study by Nathan Medeiros-Ward, Joel Cooper, and David Strayer in
the June, 2014 issue of the Journal of Experimental Psychology: General.
As they point out, recent theories
of attention suggest that when we perform complex tasks, we use two circuits of
behavior. One circuit focuses on task
performance, while the other focuses on the strategy for the task we are
performing. When driving, the
lower-level circuit (called the inner
loop of attention) is involved in aspects of driving like keeping the car
in the proper lane. The higher-level
circuit (called the outer loop of
attention) is involved in aspects of driving like dealing with unpredictable
elements of the environment (cars, wind, and pedestrians). In tasks like typing at the computer, the
inner loop controls the typing of letters on the keyboard, while the outer loop
controls the selection of words in a sentence.
To explore these aspects of
attention, the researchers had participants drive in a simulator. Participants were driving down a straight
highway. The difficulty of the task was
manipulated by changing the wind. The
more unpredictable the wind, the harder it was to keep the car in the lane.
The researchers also manipulated
the complexity of a second task that participants had to perform. The secondary task interferes with the outer
loop. The more complex the second task,
the more that the outer loop is focused on that task rather than on driving.
Sometimes, participants did no
secondary task. Sometimes, they
performed a 0-back test in which they heard digits between zero and nine, and
had to repeat back the digit they just heard.
This task is fairly easy to do.
Sometimes, they did a 2-back test.
In a 2-back test, participants hear digits and they have to repeat the
one they heard 2 digits ago. In order to
keep doing the task, then, participants have to remember each new digit and
then say back the one they heard two digits before. This task is hard to do.
Participants drove down the
highway in each combination of wind while doing either no second task, the
0-back task, or the 2-back task. The
researchers measured how well people were able to stay in their lane as they
drove.
When participants were not doing
any secondary task at all, they were equally good at staying in their lane
regardless of the level of the wind.
When the wind was highly unpredictable, then participants got much worse
as the secondary task got harder. That
is the typical finding in multitasking.
Interestingly, when the wind was
only moderately unpredictable, people were not strongly affected by the
secondary task. They were reasonably
good at staying in their lane regardless of how difficult the secondary task
got. And when the wind was highly
predictable, participants actually got better
as the secondary task got harder.
What is going on here?
When the driving task is very
easy, then the inner loop guides driving, but the outer loop does not have much
to do. So, it tends to monitor how the
inner loop is doing. Unfortunately,
paying attention to a skilled task can actually make performance of that task
worse. That is one reason why skilled
golfers and tennis players have trouble with their swings when they pay
attention to the mechanics of their swing.
In this case, the complex secondary task occupies the outer loop, and
lets the inner loop do its job.
When the driving task is vary
hard, though, the inner loop guides driving, while the outer loop handles the
disruptions caused by the wind. These
two systems function well together. When
the outer loop is kept busy by the difficult secondary task, then it cannot
monitor the unpredictable wind as carefully, and driving suffers.
What does this mean for driving?
Most of the time, driving is
fairly easy. There are few unpredictable
events. As a result, most people
actually drive reasonably well while they are talking on the cell phone. Unfortunately, it is impossible to know when
unpredictable events will happen (by definition), and so when performance
suffers while driving, it can be disastrous.
That is why it is important to avoid distracted driving.
Just because participants in this
study actually improved when they were distracted is not a good excuse to
multitask when you are driving. Remember
that the easy driving task in this study just required staying in a straight
lane with no other cars, pedestrians, or wind.
Real driving has many more potentially unpredictable aspects than
that. As a result, your outer loop has
plenty to do most of the time when you are driving.