After one drink, most study participants overlooked an ape onscreen

So you think you can drive just fine after only one stiff drink?

New research by the University of Washington may make you think again: Most of the study participants who had had only one cocktail didn't even notice a gorilla walking through the middle of a ballgame.

That's right. The UW researchers tested people while they focused intently on a single task — counting the number of basketball passes in a video. Most of them couldn't see much else, such as realize that the clip features a woman in an ape suit who suddenly walks to center screen, beats her chest and exits — a nine-second cameo.

They were twice as likely to miss it as nondrinkers.

"We were very surprised to see how strong the results were," said Seema Clifasefi, who led the research in the UW's Department of Psychology.

The study was small — only 46 subjects — but it could have implications for drunken-driving laws if expanded research shows similar results, she said.

Clifasefi and colleagues at Victoria University of Wellington, New Zealand, conducted the pilot study with volunteers between 21 and 35 years old. Half got plain tonic water. But the other half got vodka tonics stiff enough, based on their weight and gender, to raise their blood-alcohol content to 0.04 percent, or half the legal limit for driving in Washington. None of the participants knew for certain what they were getting.

Each participant had 10 minutes to down the drinks. Then they were each shown a video of two three-person teams passing a basketball and asked to count the number of passes.

Among the participants, only four of those who got vodka, or about 18 percent, saw the gorilla. Of the tonic-only crowd, 11, or about 46 percent, spotted the ape.

The results suggest that mildly intoxicated drivers, focused intently on their speed to keep from being stopped by the police, might not see pedestrians or other vehicles, the researchers said.

It indicates that "even having one stiff drink can make you blind drunk," the researchers reported in the current edition of the journal Applied Cognitive Psychology.

Previous research has picked up on what scientists call "inattentional blindness."

A 1999 study at Harvard using the same video showed that even without alcohol, about half of the participants missed the gorilla. And several studies by Elizabeth Loftus, formerly of the UW, showed that witnesses to crimes involving weapons often couldn't recall details about the assailant because they were too focused on the weapon.

Clifasefi said she hopes to extend her current research to include about 200 participants and to test them on a driving simulator.

Warren King: 206-464-2247 or wking@seattletimes.com