When Bradley Cooper visited Jimmy Fallon on "The Tonight Show" Friday, the two attempted to talk about Cooper’s turn in the title role of a Broadway production of “The Elephant Man.” Instead Fallon and Cooper collapsed into giggles for more than 10 minutes. They tried, mostly unsuccessfully, to complete the interview through stifled guffaws and outbursts of chuckles.

“I’ve had those moments, and when you’re in them, you can’t get out of them,” said Matt Lauer on TODAY while interviewing Cooper about the play Tuesday.

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Fallon was known for breaking character during his time on "Saturday Night Live," but even serious types can't stop laughing — it's an uncontrolled reflex, experts say. Sure, people fake laughs during work, er um, awkward conversations, but genuine giggles are much like heart beats. A complex network of nerves influences whether people chuckle, according to Stanford University researchers. It’s why people sometimes laugh during funerals or in the middle of a final.



In 2010, Robert Provine, author of “Laughter: A Scientific Investigation” and a professor at the University of Maryland, Baltimore County, told NBC News:

"All laughter is unconscious," he said. "You do not choose to laugh the way you choose to speak."

Even if Cooper and Fallon wanted to, the two couldn’t stop.

And laughter and humor aren’t as closely tied as people might think. Babies laugh without understanding a joke or that knowing that pratfalls are hilarious, according to Provine.

During the "Tonight Show" interview, Cooper and Fallon simply giggle at each other. No one says anything particularly humorous. It doesn't matter, the laughter is caused by another person who is in on it.

Sure, a funny video can cause a person to laugh out loud alone at her desk, but oftentimes giggling occurs because of another person. Cooper and Fallon fed into each other’s laughter, but at one point an audience member laughs and two erupt in giggles again.



Laughing exists as another form of communication. It’s a way to signal feelings. Even animals laugh — mice do when tickled (who knew you could tickle mice?); chimps do when they wrestle.

So when laughter overcomes you, don’t worry about it. You’re powerless to stop it anyway.