One Stiff Drink May Lead to Blind Drunkenness

25/07/06 The study showed that subjects who were mildly intoxicated (at half the legal intoxication limit in the US) were heavily compromised in their ability to notice an unexpected visual object when they were focused on another simple task.

The phenomenon, known as 'Inattentional blindness' – where unexpected, yet salient objects appear in the visual fields but fail to be detected while subjects are focused on another task– has been demonstrated under various conditions, but this is the first instance to show that these visual errors become even more likely under the influence of alcohol.

The experiment involved giving subjects 10 minutes to consume beverages which, unbeknownst to them either contained alcohol or did not. The subjects then watched 25 seconds of a video clip showing two teams of three people playing with a ball and were instructed to count the ball passes. Part way through the video clip, an individual dressed in a gorilla suit appeared on the screen, walked directly through the players, beat its chest and then walked away.. Subjects who were mildly intoxicated were twice as likely to miss seeing the gorilla, even though it had screen time of over a third of the video.

Although the research did not directly test driving aptitude, the implications for driving could be serious. "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." Says study lead author Dr. Seema Clifasefi of the University of Washington.

"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."