Here’s the situation. You’re hanging out with a few friends, two of them share an inside joke, they start laughing, and then you start laughing. The joke makes zero sense to you, has nothing to do with you, yet, you can’t help but chuckle. Yes, my friends. Laughter truly is contagious. It’s science, people!

NBC News got a quote from a neuroscientist (I told you it was science) from University College London. “We’ve known for some time that when we are talking to someone, we often mirror their behavior, copying the words they use and mimicking their gestures. Now we’ve shown that the same appears to apply to laughter, too – at least at the level of the brain.”

Don’t believe it? Maybe you’re just a miserable person. Let’s see if it works. Try watching this video without cracking a smile. If it doesn’t AT LEAST make you smile, check your pulse.