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.