‘Tis the season to start columns with the phrase ’tis the season…and, if you’re fortunate, to laugh a lot, at parties, at kids, at TV Christmas specials–or just because other people are laughing.
Why is laughter contagious? A new study, just published in the Journal of Neuroscience, provides a hint.
Researchers at University College London and Imperial College London played a series of sounds to volunteers while measuring their brain response using an fMRI (functional magnetic resonance imaging) scanner. The series included both positive (laughter or cheering) and negative (screaming or retching) sounds.
The scientists found that all of the sounds “lit up” the premotor cortical region, the area of the brain that prepares the facial muscles for an appropriate response, but positive sounds produced a greater response than negative sounds. In other words, we’re more likely to want to laugh along with someone who is laughing than to scream along with someone who is screaming. (Although screaming can be a positive sound, too, in the context of, say, a roller-coaster ride, in which case perhaps it’s just as contagious as laughter. The researchers didn’t test this hypothesis, probably because it would be difficult to fit an fMRI scanner onto a roller coaster.)
The contagiousness of laughter is probably part and parcel of our well-known tendency to mirror the words and gestures (and, unless we’re really careful, accents) of people we talk to…and an adaptation that helps individuals bond together into groups.
Evidence of the communitarian importance of shared laughter was found in the mid-1990s by Robert Provine, a professor of psychology at the University of Maryland in Baltimore, whose research revealed that people at home alone are six times less likely to smile, four times less likely to speak, and 30 times less likely to laugh than when they are out with other people.
Interestingly, he also found that in mixed-sex social situations more laughter occurred when women were listening to men than the other way around–not because men are funnier—sorry, guys!–but, Provine believed, because women are better listeners and more likely to encourage their conversational partners to keep talking.
Which ties nicely into the fact that not all laughter is spontaneous: sometimes we laugh even when things aren’t all that funny (again, sorry, guy!) because we’ve evolved the ability to use laughter for other purposes than registering amusement.
Biologists from Binghamton University researched the evolutionary roots of two types of laughter: “stimulus-driven laughter,” laughter in response to something humorous or because people around you are laughing, and “self-generated and strategic” laughter.
The Binghamton biologists (a funny phrase if I’ve ever heard one) said stimulus-driven laughter evolved from “ape play-panting” between four million and two million years ago, and “promoted community play during fleeting periods of safety.” Then, around two million years ago, our ancestors evolved the ability to control their facial muscles—which allowed laughter to be used consciously for “smoothing conversational interaction, appeasing others, inducing favorable stances in them, or downright laughing at people that are not liked.
Well, bah-humbug! That’s not very festive, so let’s return instead to a special kind of laughter specific to the season: the most famous laugh in the world, Santa’s “Ho, ho, ho!”
Apparently it’s not just famous, it’s unique. Ordinary people just don’t laugh like that.
In 2001 psychologists at Vanderbilt and Cornell Universities reported that they had studied 1,024 “laughter episodes” (which makes them sound like some kind of seizure, but never mind) from 97 young adults as they watched funny video clips. They found more sex-related differences—men, it seems, are more likely to grunt or snort while laughing, whereas women’s laughs tend to be more song-like—but one thing they didn’t find was anyone laughing “Ho, ho, ho!” Or, for that matter, “Tee-hee-hee” or even the classic “Ha-ha!” Instead, the predominant sound was a neutral “huh-huh.”
However, the researchers also found that a high level of emotional arousal produced strange effects in the sound of laughs, which could mean Santa laughs the way he does either because he’s under a lot of stress (and who wouldn’t be, in his position?) or simply because—and I think this is more likely—he loves Christmas so much.
And when the guy in the big red suit laughs, and my five-year-old daughter laughs with him, you know what? I feel like laughing, too.
So, “Ho, ho, ho!” to you and yours, and the very happiest—and laughiest!—of Christmases.