A little alcohol clouds the 'oops' factor: study

Dutch researchers say drinking two glasses of wine can seriously impair a person's judgement.

Scientists at the University of Amsterdam say a blood alcohol level of .04 (.08 is the legal limit for driving) can cloud a person's ability to recognize they've made a mistake.

The results are published in the journal Science.

Lead researcher Richard Ridderinkhof says his team monitored an area of the brain called the anterior cingulate cortex, which is involved in judgement.

He says the cortex is the one that triggers the "oops" response signaled by a brain wave.

The team tested a group of men who were all social drinkers. They gave them either an alcohol-free wine or enough wine to raise their blood alcohol levels to between .04 and .10.

The men took a test which involved reacting to an arrow on a computer screen. Their brain activity was recorded.

The men who drank alcohol made more mistakes but their brains failed to react to them. The differences were more pronounced at the .10 level.

The .04 level (40 milligrams of alcohol per 100 millilitres of blood) can be reached by two small beers or two small servings of hard alcohol or spirits within an hour.

Ridderinkhof said women are more likely to reach those levels faster and are generally more impaired than men at those levels.

Researchers say their findings could have implications for drinking and driving laws. They say any drinking, however small, coupled with driving is a bad idea.

Previous studies have shown that people's reaction time slows when they drink and that they can make mistakes on a variety of tasks. The Dutch study takes it further by showing how alcohol can compound a person's judgement by suppressing the brain's ability to catch errors.