The hardest I ever remember laughing happened pretty recently. A friend of mine and I were walking down Boylston Street this past spring, observing people on Segways and seguing into a discussion about the strangeness of spelling and pronunciation in the English language. Somehow, the word bologna ended up being pronounced “buh-LAWG-nuh” with a bizarre pseudo-accent.

I’m not sure why I found what my friend said so funny. All I know is that I was laughing so hard that I couldn’t stay standing. I collapsed into an actual heap of laughter, right there in the street.

To any passerby, what happened must’ve seemed very strange. But laughter, if you think about it, is generally pretty strange. Scientists still don’t really know why human beings laugh. Some, like Dr. Vilayanur S. Ramachandran, propose that laughter was originally a sort of “false alarm” signal. According to Dr. Ramachandran, what all humor seems to involve is an expectation that’s followed by a sudden twist that deflates it in a certain way. The very earliest punch lines would have occurred when our ancestors thought they were in danger, then discovered that they weren’t. Laughter, he claims, is “nature’s “all’s okay’ signal.” Ever laugh when someone tripped or fell? Don’t worry . . . according to Dr. Ramachandran, you’re not a bad person—you’re relieved that no one was hurt.

There are others who take a livelier view of what makes us chuckle. Dr. Sophie Scott, a neuroscientist and stand-up comedian, also believes that laughter reflects more than a mere feeling of amusement. She notes that people are 30 times more likely to laugh around other people than by themselves and that, most of the time, people laugh while they’re speaking, not while listening to someone else. “Laughter may thus be associated more with signaling affiliation, agreement and affection than it is with amusement,” Dr. Scott writes. “It may be most accurate to consider laughter as an expression of a strongly positive social emotion, which we use to form and reinforce social relationships.”

She might be onto something. A recent study published in 2015 found that laughter between friends and laughter between strangers actually sound different. Moreover, the study revealed that listeners—966 of them, from 24 different societies—were able to distinguish between the two as reliably as 67 percent of the time. The results of the study indicate that laughter is definitely a signal, and that we use it regularly to give and identify social information.

Maybe that has something to do with why I laughed so hard with my friend that day. Of course, it might also be that “buh-LAWG-nuh” just sounds really darn funny.

Did You Know?
A study done by researchers at Loma Linda University discovered that laughter improved the short-term memories of elderly participants. Because laughter decreases stress, and stress reduces the brain’s ability to remember and encode memories, laughter is an effective way to boost recall and learning ability.