Psychologists around the world refer to it as one of the most fundamental human tendencies. Whether you’re a teenager using this article as an excuse to procrastinate on that calc homework, or a cannibalistic tribesman from Papa New Guinea dressing up in full clan regalia, it is a reaction that you will have around 20 times every day. Still don’t know what you have in common with that cannibal? Your smile, of course!

Yes, that little thing you do when you’re happy, or really angry and trying to hide it, or when you suddenly realize it’s Tender Tuesday. Smiling!

As simple a reaction as it may seem, smiling is actually one of the most expressive and beneficial things you will do all day, in addition to a universal reaction recognized in even the most remote corners of the earth. For decades now, psychologists have been studying smiles in an effort to determine what a person’s smile says about them—a lot, as it turns out.

Everything from how long you will live, to the satisfaction you will get out of life, to how happy your marriage will be; it’s all right there, hidden in your smile.

Not only does your smile predict how happy you will be in the future, it also affects how happy you are today. Right. Now. Charles Darwin called it the “facial feedback response theorem,” a fancy way of saying smiling isn’t just a way of expressing happiness, but also an action that makes you feel happier. In fact, according to a recent British study, one smile can generate the same level of brain stimulation as up to 2,000 chocolate bars, without a fraction of the calories 😉

In Sweden, scientists labeled smiling “evolutionarily contagious” after performing experiments, all of which showed that it is very hard to frown at someone who is smiling. Smiling actually lowers the levels of stress-enhancing hormones in the brain (such as cortisol) creating a positive response within the smiler and almost always eliciting one from the smile-ee.

In fact, smiling is so intrinsic to human nature that we have become excellent unconscious detectors of when someone is truly smiling, and when they are faking it. Those crow-feet that 40-year-old women worry about so often are actually formed by the way your eyes crinkle when you smile genuinely. While you may not notice that type of thing consciously, subconsciously, your brain reacts to those little signals and automatically mimics the smile to determine the actual feelings of the smile-er. Interestingly enough, this ability to distinguish a real smile from a phony one was shown to be extremely muted in a study in France. During the experiment, subjects were asked to judge whether a smile was real or fake with a pencil placed in their mouth making smiling impossible. Long-story short, they couldn’t.

As for those of you strong silent types who find it more appealing to frown rather than smile, it may interest you to know that frowning takes more energy than smiling. In addition, smiling has also been found not only to make you look better, but to make you look more competent as well—not something you could say about frowning…

So go ahead— do more than just say cheese. Flex a few facial muscles, form a few wrinkles, live a bit longer, make someone’s day, reduce your stress levels and feel like 2000 chocolate bars. Smile wide, smile proud! Take every chance you get to grin from ear to ear.

Answers to Guess the Smile:

 A. Mr. Moran B. Mr. Macklmoyle C. Mr. Erickson D. Nancy E. Ms. Kantro F. Daryl for the Cove G. grumpy cat 🙁 I. happy dog