Most people are aware of the obvious effects alcohol has on the brain, but research at Western University is offering new insights into what happens to our automatic responses when we drink.

Researcher Dr. Kevin Johnston says “We were really interested in finding out something about how alcohol affects different processes of thinking, if you want to call it that.”

His team wanted to see what happens to the brain’s autopilot response after a few drinks, like a person’s response when grabbing a cup of coffee that’s about to spill and make a mess.

“We tested our subjects right around the legal limit for driving, so we calculated how many drinks they'd have to have to get to the legal limit then we tested them with a breathalyzer machine."

Test subjects were measured before and after drinking on their responses to a moving object on a screen.  When told to deliberately avoid making movements when the target shifted, the drinkers found it hard to put the brakes on this autopilot response.

"It was almost as though rather than being able to override this autopilot mechanism, it just basically took off on its own after they had a few drinks," Johnston says.

The study has implications for both our understanding of how alcohol affects our brains and also how alcohol affects us doing everyday tasks.

"A real world example is like driving,” Johnston adds. “You can imagine a situation where something non-standard happens…if you've been drinking and your ability to override automatic responses is impaired it could cause you trouble in a situation like that.”

The study is published in the scientific journal PLOS ONE.