We all have a tendency to fake laugh, particularly when authority figures in our lives try to make a joke that just doesn’t land. Though it might feel rude not to laugh when your in-laws or boss tell a real clunker, pretending to do so might not be much better. It turns out, even if you think that your forced giggling sounds genuine, people are usually pretty adept at separating truly boisterous belly laughs from counterfeit chuckles. But how can they possibly know the difference?
Well, when researchers at the University of California, Los Angeles studied the acoustic and perceptual differences between real and fake laughter in 2014, they found that some of the sounds associated with genuine laughter is “really hard to fake.”
In their study, published in the journal Evolution and Human Behavior, the researches determined that subjects were only fooled by 37 percent of fake laughter. The rest of the faux LOL’s they were able to detect.
The most prominent factor distinguishing real laughter from fake laughter is duration—or, more specifically, the number of breaths taken in in between sounds. Seeing as it takes more effort and concentration to fake a laugh versus do it genuinely, people tend to pause more in between their “ha-ha’s” when they’re faking it. Evidently, that pausing is pretty noticeable.
“A fake laugh is basically an imitation of a real laugh, but produced with a slightly different set of vocal muscles controlled by a different part of our brain,” Greg Bryant, the lead UCLA researcher on the study, explained in a 2015 Washington Post article. “The result is that there are subtle features of the laugh that sound like speech, and… people are unconsciously quite sensitive to them.”
People have also proven to be emotionally sensitive to laughter as well. “Our brains are very sensitive to the social and emotional significance of laughter,” Carolyn McGettigan, a cognitive neuroscientist at Royal Holloway, University of London, told Medical Xpress.
McGettigan conducted a 2014 study that recorded participants’ brain responses as they listened to the same people produce genuine laughter by watching funny YouTube videos, versus fake laughter.
“During our study, when participants heard a laugh that was posed, they activated regions of the brain associated with mentalizing in an attempt to understand the other person’s emotional and mental state,” she said.
So, while we may understand that certain social situations sometimes require fake laughter, most of the time, our instincts and emotional intelligence are just too smart to buy into them.
According to McGettigan, that’s a good thing. “Evolutionarily speaking, it’s good to be able to detect if someone is authentically experiencing an emotion versus if they’re not,” she told Scientific American. “Because you don’t want to be fooled.”