Is laughter contagious?

couple laughing at television
Victims of the laugh track?

In 1999, Time magazine deemed the laugh track one of the 100 worst ideas of the previous century. By ranking on this list, the laugh track found itself in the company of such ill-fated concepts as aerosol cheese, Crystal Pepsi and the Titanic. The concept started off nobly enough; it was introduced in 1950 on "The Hank McCune Show" as a way to compensate for the lack of a live studio audience. As time went on, however, the canned laughter started to sound corny and trite, especially when belly laughs erupted after a not particularly funny one-liner. While they've fallen out of favor and are eschewed on many current television comedies, it's perhaps disingenuous to compare them to the Titanic. After all, though the Titanic sank, laugh tracks actually work.

No matter how ridiculous those laugh tracks sound, they do increase the chances that we'll laugh at something. We've known this since 1974, when a study published in the Journal of Personality and Social Psychology revealed that subjects were more likely to laugh and find jokes funny when the jokes were followed by the recorded sound of laughter [source: Walker]. More recently, researcher Robert Provine, an expert on laughter, has found that people don't even need the joke to laugh; he plays subjects 20 seconds of laughter on a hand-held device, and even though it's obvious that the laughter is fake, subjects smiled or laughed anyways [source: Walker]. This suggests to researchers that laughter is a contagious phenomenon.


In discussions of contagious laughter, it doesn't take long for the subject of the Tanganyika (now Tanzania) laughter epidemic to come up. In 1962, three girls studying at a boarding school in an African village begin to laugh. Then the laughter, along with other symptoms such as crying, began to spread, so much so that 95 of the 159 students at the school were afflicted [source: Provine]. The school had to be closed; upon re-opening, more than 50 pupils were again affected, and the results spread to nearby villages. By the time the laughter stopped, two and a half years later, more than 1,000 people had exhibited symptoms of the laughter epidemic.

Now, kids, don't go getting any ideas on how to get school cancelled. It's now believed that the laughter of 1962 to 1964 is due to mass psychogenic illness, or mass hysteria, brought on by stress [source: Hempelmann]. But do these events reveal the potential danger of contagious laughter? Why is laughter infectious in the first place?


Infectious Laughter

group of laughing girls
You're more likely to find your funny bone tickled in a group of people.

Here's an experiment: Try to laugh out loud, right now. Did you find it difficult? Laughter is very difficult to fake, so when we do let loose with gaggles of giggles, it's a largely involuntary action. Now think about this: Do you find yourself laughing more at films when you see them in a theater with other people, or when you're watching them at home alone on television? If you're like most people, you'll laugh more at a funny film that you see with an audience. Researcher Robert Provine has found that laughter is 30 times more frequent in groups compared to private settings [source: Provine]. That's not to say we don't find things funny when we're by ourselves, but we're more likely to smile or talk to ourselves than to roll on the floor laughing [source: Provine].

Because laughter is an involuntary action most often occurring in groups, Provine theorized that our brains likely have a laugh detector that triggers some sort of laugh generator. Researchers at University College London may have found that neural mechanism. In a 2006 study, the researchers played subjects a host of sounds while monitoring their brain's responses with a functional magnetic resonance imaging (fMRI) scanner. The subjects were played a mix of positive sounds, such as laughter and a friendly shout, as well as negative sounds, which included retching and screaming.


All of the sounds activated a part of the brain known as the premotor cortical region; this part of the brain readies our facial muscles to react to sounds. In other words, when people heard laughing, they began to smile. But don't worry; people didn't start retching as well -- responses for the negative sounds were lower, indicating that our brain is much more likely to respond to positive sounds than to negative ones [source: Thompson].

If you're worried that your brain is forcing you to laugh at things that aren't funny, consider what a boon this was to our ancestors. If laughter predated speech, as some theorists suggest, then this penchant for positivity was an important way to demonstrate friendliness. Laugher was a way to show that you meant another group no harm, that you wanted to belong. Even now, laughing is an important social tool that builds bonds between people. A laugh is a way to encourage conversation on a first date and a means to bring people together over a shared experience. Thus, it appears that the old expression is true -- laugh, and the whole world laughs with you.


Lots More Information

Related HowStuffWorks Articles

  • Angier, Natalie. "Laughs: Rhythmic Bursts of Social Glue." New York Times. Feb. 27, 1996. (June 1, 2009)
  • Hempelmann, Christian F. "The laughter of the 1962 Tanganyika 'laughter epidemic.'" Humor. March 2007.
  • Kluger, Jeffrey. "The Funny Thing About Laughter." Time. Jan. 17, 2005.
  • Provine, Robert R. "Laughter: A Scientific Investigation." Viking Penguin. 2000.
  • Provine, Robert R. "The Science of Laughter." Psychology Today. November/December 2000. (June 1, 2009)
  • "The 100 Worst Ideas of the Century." Time. 1999. (June 1, 2009)
  • Thompson, Andrea. "Study: Laughter Really is Contagious." LiveScience. Dec. 12, 2006. (June 1, 2009)
  • Tierney, John. "What's So Funny? Well, Maybe Nothing." New York Times. March 13, 2007. (June 1, 2009)
  • Walker, Rob. "The Lives They Lived; Making Us Laugh." New York Times. Dec. 28, 2003. (June 1, 2009)