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New Study Looks at Perception of Sobriety and Actual Ability to Drive

Posted in Drunk Driving

A new study sheds light on why some people get behind the wheel after drinking alcohol, believing that they’re sober enough to drive. This is the first study to examine the ways in which cognitive abilities are affected during rising and declining blood alcohol levels, as well as the differences between self-evaluation of recovery from drinking and actual recovery.

Peter J. Snyder, PhD, professor of neurology at The Warren Alpert Medical School of Brown University and vice president of research for Lifespan, and his colleagues created a test that examines rising and falling blood alcohol levels and how they affect functions that are required for driving safely. The researchers tested a group of college students, comparing self-reported feelings of being drunk and the students’ actual ability to get through a hidden maze learning task over an 8-hour period, during which their blood alcohol level increased and declined.

Snyder said that the new study shows that executive functions don’t recover as quickly as motor speed and information processing speed, but the feeling of being drunk does recover more quickly. This explains why some people think they are able to drive after drinking, although in reality they aren’t.

Participants drank alcohol over an 8-hour period, brining their blood alcohol level to 0.10 percent and then returning to a normal level. Throughout the 8 hours, they were asked to perform a hidden maze learning test on a touch-screen computer. Without alcohol, most young, healthy individuals would make very few mistakes in the maze. As blood alcohol levels rose, the mistakes increased significantly. Their mistakes also didn’t decline as quickly as their subjective feeling of being drunk.

Snyder said that it’s important to recognize that as people become drunk, they make more errors, and the recovery of these cognitive impairments is slower and more closely linked to their blood alcohol level than how quickly they may feel that they’re no longer drunk. These cognitive functions are important for driving and making judgments, such as changing lanes and entering intersections.

In conclusion, the researchers said that because the subjective feeling of being less drunk is more rapid than actual recovery, many people believe they’re able to drive while still drunk. This finding could be used for education and prevention strategies, as letting people see that their own reports of intoxication don’t correlate with their cognitive performance might help them make better decisions when considering whether to drive after drinking.

Source: Science Daily, Why Drunk Drivers May Get Behind the Wheel, August 18, 2010