While Ella Wheeler Wilcox’s opening line from an otherwise somber poem “Solitude” is often quoted out of context, she was definitely on to something that may be older than language itself. And it’s something that’s always been important for our relationships with each other.

Being in a room full of laughing people is quite a joyful experience, unless of course you’re the butt of the joke, but the warmth you get from being part of a communal chuckle is like no other. And our brains can play along, even when we don’t expect it to. According to LiveScience, Scientists from University College London found that when we encounter positive emotions in a group setting our brains automatically get us ready to mirror the behavior of others. That explains why hearing people laugh is often so funny. Our bodies are getting ready to join them.

We may have had this response in us before we even developed language. Jaak Panksepp, a neuroscientist at Bowling Green State University suggested that human ancestors have laughed in groups before they could speak. We know that the act of laughing starts at an age from before we can speak or walk, which could suggest that it’s a deep-seated brain function.

The enjoyment we get from laughter is healthy too. It’s a quick fire way to release endorphins in the brain, the body’s natural feel-good hormone that gives us a sense of well-being. It also helps decrease stress hormones, relaxes the body, and could even burn a few calories. So it’s no wonder we love a hearty, belly laugh with friends and strangers, even if we don’t expect to. If laughter is the best medicine, so take a contagious dose of it with this video taken on a train in the U.K.

https://www.youtube.com/watch?v=pER3fa_mTo8&t=26s