Only rare "supertaskers" can balance driving, cellphone use

The past few years have seen a series of studies that indicate the distractions of cellphone use have an impact on driving skills that rivals intoxication, and various governments are responding by instituting bans on the use of tech toys behind the wheel. Despite laws, extensive evidence and a reasonable degree of public awareness, there’s no shortage of people using phones behind the wheel, which suggests that many drivers have a great deal of confidence in their multitasking ability. A new study that will be released by the journal Psychonomic Bulletin and Review suggests that, even though most of those people probably are bad at multitasking, a small percent of the population positively excels at it.

The basic idea behind the new study is that even though the studies of distracted drivers are pretty definitive, they typically only measure group behavior, which may obscure a small sub-population that’s the exception to the rule. So, its authors set up a standard test of distracted driving, and looked for people who had performance that represented an exception to the group trend.

The driving portion of the test was handled by a commercial product called PatrolSim, which used a simulated 30-mile stretch of multilane highway. As faster-moving traffic passed in the left lane, subjects were asked to follow a pace car in the right that would sporadically apply the brakes. The response time of the subjects—how long they took to notice and apply their own brakes—served as a measure of driving attentiveness.

For the distraction, the subjects were given a cell phone that was used to administer an audible version of the OSPAN memory task. OSPAN involves a series of simple true/false math problems (a sample: is (3/1) -1 = 2?), interspersed with words. The subjects are asked to answer the math questions as they appear, and then recall the words in order once anywhere from two to five instances were presented. Performance on OSPAN appears to parallel that of a number of classical memory tests.

As expected, most of the subjects did worse on both the driving and memory tasks when they were asked to perform them simultaneously. Driving distance and braking response times shot up, while both memory and math performance dropped relative to single-task scores.

But there were exceptions—a grand total of five (three male, two female) out of the initial group of 200 subjects. Making sure that the high dual-tasking performance wasn’t due to the individuals having bombed the single-task tests, either unintentionally or on purpose, ensured that their single-task scores weren’t below average. In fact, they were typically above average and, in most cases, showed absolutely no difference between the single- and dual-task experimental setups. In fact, in the one exception, the OSPAN memory test, they actually performed better in the dual-task condition.

The small percentage of what the authors termed “supertaskers” obviously left the authors considering the possibility that it was a statistical fluke. So, they created four pools from the scores from their tests (memory, math, braking distance, and response time) and used Monte Carlo sampling to create 100,000 random scores. Supertaskers appeared in only 0.16 percent of these, which indicates that the 2.5 percent figure they saw represents a real phenomena.

Since then, the authors have identified another three supertaskers from among the University of Utah student body, and have confirmed that their exceptional performance stays stable for time spans of at least six months. They’re subjecting them to a variety of neural and behavior tests in an attempt to identify what, precisely, gives them an ability that most of us so clearly lack.

If the behavior is so apparently useful, why aren’t we all supertaskers? The paper suggests two alternative explanations. The first is simply that supertasking has only become useful in recent years, so there’s been no opportunity for evolutionary selection to cause it to be pervasive. The alternative is that supertasking comes at some sort of neural cost so, even though it’s useful, the downsides ensure that it remains limited to a small fraction of the population.

The authors also took the time to remind their readers that the supertasking population really is small, so you shouldn’t assume you’re one of them. Unfortunately, it looks like most people tend to believe they’re the exception to this rule, as the authors note, “our studies over the last decade have found that a great many people have the belief that the laws of attention do not apply to them (e.g., they have seen other drivers who are impaired while multi-tasking, but they are the exception to the rule). In fact, some readers may also be wondering if they too are supertaskers; however, we suggest that the odds of this are against them.”

Psychonomic Bulletin and Review, 2010. DOI unavailable; preprint available via the authors.