NOVA - Official Website | Evolution of Laughter

What Makes Us Human.

PBS Airdate: October 10, 2012

DAVID POGUE: We may enter the world crying, but after about three months, we humans start doing something really weird. We begin to laugh.

Home videos on the Web featuring baby laughter get tens of millions of hits. Why would so many people feel compelled to watch babies simply laughing?

Dr. Gina Mireault studies baby laughter. She says home movies, posted on the Web, support her research in the lab, revealing that laughter is less about humor and more about the serious business of survival.

GINA MIREAULT (Johnson State College): Smiling and laughter are hardwired into the system. Newborn babies smile, they smile in their sleep. It's an involuntary reflex, so this is something that they come equipped to do, ready to do.

DAVID POGUE: Let's face it, human babies are weak creatures, more vulnerable than any other animal babies. We can't walk, we can't talk, we can't get our own food.

But we can laugh and, according to Mireault, that's a powerful secret weapon to get adults fully our side.

GINA MIREAULT: And what we found, with these very young babies, is that, when you tell parents, "Do whatever you normally do to get the baby to laugh," parents do some really outlandish things.

MOTHER: Peekaboo!

GINA MIREAULT: So much so, that, by the time the baby is six months of age, they generally require parents to ratchet it up.

DAVID POGUE: You know, you do start to wonder who's performing for whom here.

GINA MIREAULT: Laughter is irresistible. These are, these are really critical communicative signals that babies give to parents, when the baby is particularly helpless.

I think laughter is central to survival, because it's part of what binds us together.

DAVID POGUE: We have a tooth coming in!

But do animals other than humans actually laugh?

Dave Oehler, at the Cincinnati Zoo, is going to help me find out.

I've wanted to do this since I was five years old!

DAVID OEHLER (Cincinnati Zoo & Botanical Garden): There you go. Go ahead and reach down and touch him. There you go.

DAVID POGUE: Lo and behold, on my first try, success!

He's laughing. I'm tickling this penguin, and he's laughing.

DAVE OEHLER: Well, actually…

DAVID POGUE: That's amazing. That awesome. That's…

DAVE OEHLER: …he's not ticklish.

That's what a male does when they want to court a female and then say "Are you ready to breed?"

DAVID POGUE: I see. So it wasn't tickling so much as…

DAVE OEHLER: …tickling. Ha, ha, ha.

DAVID POGUE: Yes, I did. Yes I did. Yeah!

Getting animals to laugh turns out to be quite a challenge.

Who's a good walking stick bug?

I guess not.

Oh, so this is the mythical kookaburra!

And where does one, where does one tickle an elephant?

DAVE OEHLER: Right behind the ears. That's where she loves it.

DAVID POGUE: Who's a good girl? Oh, my gosh! It doesn't sound all that laughy. It sounds a little bit more like: "I'm going to kill you now."

DAVE OEHLER: Be a good girl, come on.

Good girl, all right. Come back over here. Come back over here.

DAVID POGUE: But what about our closest relatives, the great apes? Do they laugh.

In the wild, when apes play wrestle, they make a distinctive sound that some scientists believe is a form of laughter.

Zoologist Marina Davila-Ross has been studying and recording primate laughter. Today, she's observing an orphaned gorilla, named Okanda, during a play session with his caretaker at the Stuttgart Zoo, in Germany.

So, you have done some tickling?

MARINA DAVILA-ROSS (University of Portsmouth): I have done some tickling.

DAVID POGUE: On your resume somewhere it says…

MARINA DAVILA-ROSS: Yes.

DAVID POGUE: …"Tickled baby apes?

MARINA DAVILA-ROSS: Yes. Ha, ha.

BEA (Okanda's Caretaker): gibt es die flasche! Jetzt gibt es die flasche! Ohh!

MARINA DAVILA-ROSS: The caretaker is right now play-biting, and that's often inducing a lot of laughter in the little ones.

And they're particularly ticklish around the neck and armpits.

BABY GORILLA: Huff, huff, huff.

MARINA DAVILA-ROSS: He's laughing right now.

BABY GORILLA: Huff, huff, huff.

DAVID POGUE: He looks like he's laughing.

Marina collected sounds from all five of the great ape babies being tickled. In order of relation to humans, orangutans are the most distant from us genetically; gorillas are a bit closer; then come chimpanzees and bonobos; and then us, humans.

Listen carefully as the sound made by these five primates changes, on its way up the genetic family tree:baby organutan,.

…gorilla,.

…chimpanzee,.

…bonobo.

…and human.

Analyzing these sounds convinced Marina she was hearing the evolution of laughter. What begins as just panting in the orangutan, becomes more controlled in the vocalized "ha-ha" sound of the bonobo and finally the humans.

MARINA DAVILA-ROSS: Laughter of humans sounds different, particularly because they are voiced. It's the melodic laughter, this "ha ha" kind of laughter.

DAVID POGUE: Apes seem to use their noisy laughter only in one situation, when they're rough-housing. In other words, when they are saying, "I may seem to be trying to kill you, but I'm just playing around right now." And they always use the same kind of panting laughter.

Since the last common ancestor, at least 6,000,000 years ago, it seems we were evolving to voice our laughter, but why?.

In a lab, at Georgia State University, I'm volunteering to have my laughter recorded, part of a serious study looking at the different ways humans laugh.

Psychologist Michael Owren uses acoustical models to compare laughter sounds.

MICHAEL OWREN (Georgia State University): Let me play this for you.

You can see this voiced laughter, with the mouth open.

DAVID POGUE: So, "voiced" laugh, when you say voiced laughter you mean with a vowel?.

MICHAEL OWREN: Exactly.

DAVID POGUE: Like "Ha, ha, ha."

Owren worked with Marina Davila-Ross to analyze her collection of primate sounds, and he agrees that laughter plays a crucial role in human development.

MICHAEL OWREN: Actually, the majority of laughter does not happen in response to humor, it happens, simply in the course of everyday conversation and doesn't necessarily follow anything that's particularly funny: "Can I borrow your car, Dad? Ha, ha, ha".

DAVID POGUE: These little laughs that punctuate our speech? Owren says they're like a kind of glue, connecting us to one another and ultimately making us more successful as a species.

But how does that make me have more babies?

MICHAEL OWREN: It makes you have more babies, well, not you in particular, but it made human ancestors, potentially, have more babies, by allowing individuals who are not biologically related to one another, to cooperate. That takes emotional bonding.

DAVID POGUE: So laughter leads to bonding; bonding leads to babies; babies…well, you get the idea.

And a world without laughter, it seems, would not only be a lot less fun, it would also be a lot less human.

Soon after the dawn of television
there came…
The laugh track.
In 1950 canned laughter
Made its debut…
…on a program called
The Hank McCune Show.
Research shows that a laugh track
Can make jokes seem funnier.
The show was cancelled
after 3 months.
But the laugh track lives on.

What Makes Us Human?

HOST: David Pogue
WRITTEN, PRODUCED AND DIRECTED BY: David Murdock

Zeresenay Alemseged Profile

WRITTEN AND DIRECTED BY: Joshua Seftel
PRODUCED BY: Joshua Seftel & Erika Frankel

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