Even One Strong Drink May Impair Judgment
Study subjects' attention levels fell, despite being below the legal blood-alcohol limit
FRIDAY, June 30 (HealthDay News) -- 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."
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.
-- Diana Kohnle
SOURCES: Journal of Applied Cognitive Psychology, news release, June 29, 2006
Copyright © 2006 ScoutNews LLC. All rights reserved.
'Ape-earances' can be deceiving for many under the influence of alcohol
June 30, 2006
It's pretty difficult to overlook the proverbial 800-pound gorilla, or even an average-size person dressed in a gorilla suit. But a new study indicates that people who were given a simple visual task while mildly intoxicated were twice as likely to have missed seeing the person in a gorilla suit than were people who were not under the influence of alcohol.
The study, appearing in the current issue of the Journal of Applied Cognitive Psychology, is the first to show visual errors caused by "inattentional blindness" are more likely to occur under the influence of alcohol. This phenomenon occurs when important, but unexpected, objects appear in the visual field but are not detected when people are focused on another task, according to Seema Clifasefi, a postdoctoral psychology researcher at the University of Washington.
While the research, a pilot study, did not test driving aptitude, the study has strong implications for people operating motor vehicles after consuming alcohol, according to Clifasefi, who is affiliated with the UW's Addictive Behaviors Research Center.
"Driving requires our full attention. We need to perceive information from a variety of sources when we are driving, but alcohol reduces our ability to multi-task. So we focus on one thing at the expense of everything else," she said.
"Say you have been at a party and are driving home after having a couple of drinks. You don't want to be stopped for speeding, so you keep eyeing the speedometer. Our research shows that you will miss other things going on around you, perhaps even a pedestrian trying to cross the street." In the study, 46 adults ranging in age from 21 to 35 were brought into a bar-like setting. Half of them were given drinks containing alcohol to bring their blood alcohol level up to 0.04 – half the legal level for being drunk in most states. The other half were given drinks containing no liquor.
After the volunteers had their blood alcohol levels measured by a breath test, they were taken to a computer monitor and asked to watch a 25-second film clip. The clip showed people playing with a ball and the volunteers were told to count the number of times the ball was passed from one person to another. In the middle of the clip a person dressed in a gorilla suit appeared, walked among the players, beat its chest and then walked away.
Afterward, the subjects were asked if they saw the gorilla. Just 18 percent of the drinkers said they noticed the gorilla while 46 percent of the sober subjects indicated they saw the gorilla.
In the future, Clifasefi hopes to do a larger study testing inattentional blindness using a driving simulator.
The National Institute of Alcohol Abuse and Alcoholism funded the research. Co-authors of the study are Melanie Takarangi, a doctoral student at Victoria University of Wellington in New Zealand and Jonah Bergman, a recent UW graduate.
For more information, contact Clifasefi at (206) 543-3452 or seemac@u.washington.edu
Contact: Joel Schwarz
joels@u.washington.edu
206-543-2580
University of Washington