We’ve already explained how to live forever— now here’s the scoop on eternal youth. A new study suggests smiling can keep us young, at least at face valueLet me guess how old you are: Effects of age, gender, and facial expression on perceptions of age. Voelkle, MC, Ebner NC, Lindenberger U, et al. Psychology and Aging, 2001 Sep 5.. Researchers propose people associate smiling faces with positive, attractive, and youthful qualities, and that flexing muscles in the face can conceal what we really look like.

The study was one big guessing game: 154 men and women were asked to identify the ages of over 2,000 faces that showed varying emotions, like happiness, fear, sadness, disgust, and plain old indifference. Subjects guessed correctly most often when faces wore a neutral expression (ever wonder why people are told not to smile in a passport photo?), but people were most likely to underestimate the age of a smiling face. And for the ladies out there, here’s a fun fact: Data revealed older female faces looked more than three years younger than their male competitors.

For those who aren’t concerned about looking a day over their age, don’t quit grinning. Flashing a smile works magic in more ways than one. We may all just feel happier in the long run.