If you’ve taken a photo for a passport before, you’ve probably have heard it time and time again: Don’t smile. Just stare straight into the camera with a blank stare so you look as neutral as possible. Smiling is not allowed.

However, it’s actually a highly misconceived notion that you’re not allowed to smile in passport photos. You can smile, it just has to be a low-key “natural smile,” not an overly excited smile. And there’s actually a huge benefit to doing this low-key smile in your passport photo.

One interesting study recently found that going for a “natural smile” in your photo might be useful in helping to prevent identity fraud.

The study, performed by researchers at the University of York in England, found that it was much easier time to identify people who were smiling than it was to identify the same people when they had neutral expressions on their faces. Thus, identity thieves are more likely to get caught if they’re trying to mimic your smile vs. a neutral expression.

“Photo ID is a significant part of our lives and yet we know that the human brain has a hard time matching photos of people to other photos and matching photos with the real-life person,” said Dr. Mila Mileva at the University of York’s Department of Psychology, who led the research. “Identity fraud is a real problem on many levels, so it is important that we do more research in this area to see how we can improve methods of identification.”

There were actually three studies performed among the research. First, the team had 40 people match 60 photos of people that had neutral facial expressions to photos of them with an open-mouth smiling face. The second study had those participants comparing the neutral face expressions to images of a closed smiling face. And lastly, the team had 34 of the participants attempt to match images that just displayed the lower part of the face.

All three of the pieces of the study showed that it appeared easier to match the open mouth smile was displayed, and harder to identify the neutral image or a closed mouth smile.

“Our research suggests that replacing the neutral expression we usually use when taking identification photographs with an open mouth smile, can make face matching an easier decision,” said Dr. Mileva. “As soon as there’s a mismatch in emotional expression—comparing a smiling and a neutral image for example—the matching accuracy drops substantially.”

“We also had success in showing that an open mouth smile can help people to tell two similarly looking, but different people apart which is critical when checking photo identification,” she added.

Dr. Mileva and other experts involved in the research believe that if we were to require people to smile in ID photos, it may work as a way to improve identification and lessen the amount of identity fraud in the future. Another option they mention in the study is to embed a smiling picture in the chip, so that the passport officials can have access to both a neutral and a smiling image to help them make a decision if they find themselves in an event such as identify fraud.

What do you think of this study? Are you going to try a low-key smile the next time you take a passport photo?

If you want to take your own passport photo, check out the tips in this video below!