In Brief

Have you ever zoned out and missed your freeway exit, only to realize it a half-second too late? You're not alone, according to study results in November's Psychological Science (Vol. 18, No. 11). Researchers found that study participants who were asked to find particular targets on a computer screen often missed them-just as drivers miss exits and baggage screeners overlook potential threats.

Duke University psychologist Stephen Mitroff, PhD, and graduate psychology student Mathias Fleck had 20 students sit in front of a computer and look at a screen full of items that fit into five categories: toys, fruits and veggies, clothes, birds and tools. They instructed the participants to quickly press a button indicating whether a tool was present or not. Then a new array would pop up and the participants would repeat the process.

Out of 1,000 trials, only 20 arrays contained a tool, so participants tended to get in a speedy rhythm of hitting "no" repeatedly, Mitroff says. On average, they missed 31 percent of the targets.

"You can't stop that fast potent motor response," Mitroff says.

But when participants had the option of correcting a choice immediately after they made it, that error rate was cut by two-thirds. That finding suggests that participants' mistakes resulted from execution errors, not perception mistakes, Mitroff explains.

The real-life upshot? Baggage screeners and radiologists will be more precise when they consciously take their time for each search, Mitroff says.

-M. Price