Smiling is awesome — there’s no better way to say it. Stressed out and angry? Curling those lips upward will make you feel a little better. It’ll also show that you’re a person who can be trusted. Then there’s the obvious fact we do it whenever happiness strikes. While you reminisce (and possibly smile) about that last cup of coffee you had or, say, the possibility of going on a nice vacation, here’s something you might not want to hear — especially if you’re worried about aging. A new study has found people tend to perceive those who smile as looking older.

“When people smiled, they were perceived as between one year to almost two years older than when they were presented bearing a neutral expression,” Dr. Tzvi Ganel, a psychology professor at Ben-Gurion University in Israel, told Real Clear Science. His study, published in the journal Psychonomic Bulletin & Review, refutes a previous one, which until now had been the only other study to test perceptions related to smiling and age.

In the previous study, researchers from the Max Planck Institute in Germany asked participants to rate the age of people’s faces shown in different photos as angry, fearful, disgusted, happy, sad, and neutral. They found participants were more likely to rate smiling and neutral faces as looking younger when compared to the rest. Ganel saw this study’s design as flawed, suggesting that the participants’ perceptions became biased after viewing the other facial expressions.

So, Ganel took only neutral and smiling photographs of 220 people, and showed them to a total of 60 participants over the course of three studies. The first looked at participants’ general perceptions of the faces, and found smiling ones were more often viewed as being older. His next two experiments sought to figure out why this happened. Noting how prominent wrinkles were on the smiling faces, particularly around the eyes, he altered the photos so they made the wrinkles even more noticeable, and then showed them to 20 participants. In the other, the photos were blurred to shroud the wrinkles, after which another 20 participants judged them. Both experiments turned up the same results, with more people saying the smiling faces looked older.

One limitation of the study is that it was college students rating the age of people who were actually aged 20 to 40 — it’s pretty difficult for people to rate the age of others outside of their age group. There isn't really a takeaway from this study either, except for maybe the fact people with RBF (look here for what that means) can take solace in their RBF. Or maybe, it’s just a reason to smile or not smile, depending on how old you want to look.

Source: Ganel T. Smiling makes you look older. Psychonomic Bulletin & Review. 2015.