I’ll admit, I smile all the time. But honestly, it’s not because I want to. Sometimes I feel like I have to, especially to downplay unwanted attention or awkward situations. And in this day and age, the last thing I need is for science to give strangers more reasons to say, “Give me a smile.”

I get it. A genuine smile is more than just a face-lift. It can positively impact your life and has the power to change how other people perceive you.

But I’d like to save my best smiles for those who are worth it. The question is, what makes a good smile, and how do I know when to use it?

A new study — aptly titled “Dynamic properties of successful smiles” — breaks down what makes a successful smile and its effects on others.

So, what, according to science, makes a perfect smile?

Well, there isn’t just one path to a successful smile. No human face is exactly the same.

However, there’s a set of parameters that a successful smile falls under. It’s usually a balance between mouth angle (from center of the lip to corner of top lip and bottom lip), extent of the smile (length of smile from center of lower lip to corner of right lip), and how much teeth are showing (between the upper and lower lip).

People in the study were also asked to rank smiles as “creepy or pleasant,” “fake or genuine,” and how effective they were — from very bad, bad, neutral, good, and very good.

Winning smileUnpleasant smile
The mouth angle will hit from 13 to 17 degrees.Extreme mouth angles when smiling.
The smile will extend about half to a little over half the distance from one pupil to the other.Low mouth angles paired with small width between your lips creates a “contempt” smile.
Have a smaller mouth? Showing less teeth is often better. A bigger mouth? More teeth is considered better.These same open mouth smiles can also create an expression of fear.
 

This might seem like splitting hairs, but smiling is a big psycho- and sociological deal. The study also found that people who had impaired facial movements were negatively impacted from not being able to produce a successful smile.

So you know how to smile — now what?

As someone who’s 5 feet 2 inches tall, often mistaken for being a teenager, and with no formal training in self-defense, my weapon of choice for diffusing hostile situations is to smile.

For those times in the future when I’m walking down the street, minding my own business and blasting music through my headphones, and a random stranger yells at me to, specifically, “Show my beautiful smile” — oh do I have a scientifically creepy smile to show now.

Thanks to this new study, I don’t have to give away genuine smiles to street harassers anymore. I also know what fearful smiles to avoid showing to my harassers. If anything, they should now fear me.

I’m ready to show as much teeth as I possibly can and pull up the corner of my lips to the highest degree (basically Joker status). One so uncomfortable, my aggressor has no choice but to correctly interpret it as “overall effectiveness: very bad” and “creepy.”

Street harassers everywhere, I hope you’re ready to see my beautiful smile, catered just for you and your microaggression.


Robin is an editor at Healthline.com. She believes in the power of a smile, even if she’s missing all her canine teeth. When she’s not editing, she can often be found hiding in the mystery section of bookstores or buying things she doesn’t need at the dollar section of Target. You can follow her on Instagram.