Even One Strong Drink May Impair Judgment

A study involving a chest-thumping gorilla comes with a serious message: People who think they can handle just one drink after work and still drive home safely may want to think again.
A new study found that, despite blood readings suggesting participants had reached just half the legal intoxication limit, those participants still suffered significant visual impairment after only one drink.

In the study, researchers from the University of Washington, Seattle, studied the theory of "inattentional blindness," wherein an individual fails to notice an unanticipated yet prominent object -- in this case, a gorilla -- in their field of vision while concentrating on another task or object.
To determine the effect of inattentional blindness on subjects who had been drinking, study participants were given 10 minutes to drink a beverage. The drink may or may not have been alcoholic, and the participants were not told whether or not their beverage contained alcohol.
After finishing their drinks, participants watched a 25-second video clip featuring six people playing ball. They were asked to count the number of times the ball was passed between players.

In the middle of the video, a person in a gorilla suit walked past the players on the screen, beat on its chest and then walked out of the image. The gorilla was in the scene for more than one-third of the entire video.
Participants who tested as "mildly intoxicated" were twice as likely to say they didn't see the gorilla, compared to participants who were less drunk. The findings could have serious implications for driving while mildly intoxicated, the researchers said.
"We rely on our ability to perceive a multitude of information when we drive (speed limit, road signs, other cars, etc.). If even a mild dose of alcohol compromises our ability to take in some of this information -- in other words, limits our attention span -- then it seems likely that our driving ability may also be compromised," study author Dr. Seema Clifasefi said in a prepared statement.
For example, she said, "If you've had one drink, you may be so focused on paying attention to your speed so as not to get pulled over, that you completely miss seeing the pedestrian that walks directly in front of your car."
FRIDAY, June 30 (HealthDay News) -- The study was published in the journal Applied Cognitive Psychology.
More information
The U.S. Centers for Disease Control and Prevention has more information on drinking and driving.