Drunks are aware but don't care, study shows

ST. LOUIS — A new study says that people who commit blunders while under the influence of alcohol know they’re doing it; they just don’t care.

This means buzzed or drunk people who engage in embarrassing or harmful behavior can’t blame it on not having control, said researcher Bruce Bartholow, associate professor of psychology at the University of Missouri-Columbia.

While this isn’t the first study that shows alcohol alters the behavior of those who consume it, “It’s the first to show they don’t care that they’re making mistakes,” said Bartholow, chief researcher on the study.

Brain tests during the study of 67 people in Columbia, Mo., showed that alcohol dulls a mechanism in the brain that tells individuals to put on the brakes when they realize they’re making mistakes.

When the mechanism is working, “They slow down and try not to make the mistake again, or they take corrective action,” Bartholow said.

Introduce alcohol and people are more likely to disregard the moral stop sign, he said, even though they know what they’re doing.

The study involved people between the ages of 21 and 35, students and non-students.

— Researchers gave a third of the participants drinks with enough alcohol to raise their blood levels to just under the legal driving limit of .08 percent, Bartholow said. They all got the same amount so researchers didn’t measure if the effect was gradual.

— Researchers gave a third of the participants placebo drinks; they didn’t know whether the drinks contained alcohol.

— A third consumed drinks they knew contained no alcohol.

Then the groups were given tasks designed to elicit mistakes.

Nondrinkers had normal activity in the part of the brain that regulated recognizing mistakes. Drinkers had less activity, he said.

Nondrinkers who made mistakes slowed down and tried to correct the errors, he said. Drinkers made less of an effort or simply moved past their errors, the researcher said, even though they knew they’d made errors.

Researchers also interviewed participants after the tests, which helped affirm the findings in the computer tests, he said.

“Normally, someone who makes mistakes is aware and makes an effort not to make that mistake again,” Bartholow said. The people in the alcohol group were less likely, however, to slow down and be more careful, but they realized they had made errors.

“Using alcohol doesn’t allow someone to escape culpability,” he said.