People the world over can read a relationship from a recorded laugh
The last time you read something funny, did you actually LOL, or just tell people you did? It would make sense to laugh at something funny, but sometimes it seems like we’re more likely to tell people we laughed than actually laugh at something while we’re on our own. This bias actually helps demonstrate some of the social weight carried by laughter, and how it can be a way for people to bond with each other. Aside from learning that you and a friend both find the world to be funny in the same way, a good laugh can even communicate your bond to other people around you. A study of friends’ and strangers’ laughs found that like our ability to notice a fake laugh, we can also tell when someone is laughing with someone they’re close to.
Grading others’ guffaws
The study started with college students in California who were recorded in conversation. They were prompted to read some humorous text, but weren’t told that it was their laughter that was going to be scrutinized in order to avoid making people self-conscious. Participants were paired either with close friends or strangers, and then the resulting chuckles and guffaws were isolated to be played back to people around the world. No listening participants heard the setup or the punchlines, focusing instead on identifying the relationship of the people in the one- to two-second clips of chuckles.
The average success rate of identifying friends or strangers was around 61 percent, a figure considered significant thanks to the breadth of the listeners. While the laughers were all students in California, people from any culture or language group seemed to be able to detect some universal traits about the recorded sounds. This isn’t to say that some combinations weren’t easier for some listeners— everyone around the world was good at identifying a laugh between female friends, with Americans possibly having a home advantage leading to 95 percent accuracy with those trials. Interestingly, people the world over were all tripped up by female strangers, identifying their relationship correctly less than 50 percent of the time.
That sounds sincerely funny
If the researchers are correct, part of your brain already knows what friends sound like when laughing. To try to describe it more concretely, a laugh with a friend sounds closer to a real (versus forced) laugh, in that it has more variation in loudness and pitch, with more energy overall. These traits were associated with higher arousal and spontaneity, which makes sense if the laugh is asserting a bond or agreement with someone. If you feel close and safe, it’s easier to be open, whereas you might instinctively be a be more reserved in your chuckling if you’re not sure your company shares your opinions on what’s funny.
Source: Who's Laughing Now? Listeners Can Tell if Laughers are Friends or Not by Brian Handwerk, Smithsonian