科学美国人60秒:真正的笑声会激发更多大笑

This is Scientific American's 60-second Science, I'm Susanne Bard.
"I thought you were downstair boxing chocolates.""Oh, they kicked me out of there. I kept pinching them to see what kind they were."
(CLIP: I Love Lucy with laugh track)
Laugh tracks in television shows like I Love Lucy have been encouraging us to chuckle since the 1950s. But they originated even before that with old radio shows.
"If you just put out a comedy program on the radio, people didn't necessarily realize it was supposed to be funny. So they started recording them with a live audience because then people had all the cues that they would get if they were at the theaters, say—of an audience response. And, indeed, laughter can be highly contagious."
Sophie Scott is a cognitive neuroscientist at University College London. She and her team wondered whether adding laughter to a joke could also make it seem funnier. So they scoured the Internet for the most groan-worthy jokes they could find and enlisted the help of a professional comedian to record them.
"So things like 'What's the best day for cooking? Friday. How does a dinosaur pay its bills? Using tyrannosaurus checks,' that kind of thing. And then we got people to rate how funny they were without any laughter added."
The researchers paired the jokes with both spontaneous, involuntary laughter and with laughter that had been produced on demand.
"What do you get when you ask a lemon for help? (Lemon aid)"
(CLIP: Lemonade joke with laughter)

They played these recordings to adults, some neurotypical and some on the spectrum.
"The main thing that we found was that the people with autism and the neurotypical controls were both influenced by laughter in the same way. So everybody found that the more intense the laughter, the funnier that made the joke. So everybody's rating the jokes as even funnier when they're paired with spontaneous laughter."
That is, honest, involuntary laughter cued people to perceive the jokes as funnier more than fake, forced laughter did. And that result was universal: "I think we were expecting there to be some differences for the people with autism, and we did not find them."
But autistic participants did find the jokes funnier overall.
"And I think what we're seeing here is that the people with autism are more generous in their assessment of the jokes, I suspect, although that's just one interpretation."
The study appears in the journal Current Biology.
In future laughter experiments, the researchers plan to scan participants' brains to better understand the neural systems responsible for tickling our funny bones. When they do, they may discover that dogs can't operate an MRI machine, but CAT scan.
Thanks for listening for Scientific American — 60-Second Science. I'm Susanne Bard.