If you’re looking to pace yourself during a big night out, ask the bartender to put your next draft in a straight-edged glass instead of a curvy one—new research from the U.K. found that it may slow you down.

In the study, published in the journal PLoS ONE, it took volunteers 11 minutes to drink a half pint of beer from a glass with straight edges, as opposed to just seven minutes from one that’s curved (think: your typical flute or tulip-style glass).

Why the difference? The researchers think it might be partly due to optical illusion: When asked to guess how much beer was in a glass, people were fooled more often by the curvier cups. (In other words, you might assume you’re drinking more from a straight-edged glass, so you drink slower—and vice versa.)

These results are from a laboratory, so it’s hard to say whether swapping curvy for straight will help keep you in line the next time you go out for “a few” beers. But it’s certainly worth a shot… especially if you typically over-do it.