预计阅读本页时间：-
4
TANZANIA
广告：个人专属 VPN，独立 IP，无限流量，多机房切换，还可以屏蔽广告和恶意软件，每月最低仅 5 美元
Why do we laugh?
Good news greets us in Uganda as we disembark our plane: “Uganda has defeated the outbreak of Ebola,” announces a large placard standing in the airport’s main hall. “Please have a nice stay.”
Well, that’s a relief.
We actually have a different malady in mind—one far less lethal than Ebola, but evocative nonetheless. We’re here in East Africa on the trail of the so-called 1962 Tanganyika laughter epidemic. As the story goes, in 1962 in the northwest corner of Tanganyika (a country now known as Tanzania), hundreds of people began laughing uncontrollably. The affliction, if you could call it that, spread from one person to the next, and nothing seemed to stop it. Schools shut down. Entire villages were caught in its throes. When the laughing stopped months later, a thousand people had come down with the “disease.”
Since then, the Tanganyika laughter epidemic has captured imaginations the world over. Newspaper articles have been written about it, radio shows have explored it, and documentaries have dramatized it. But many of these accounts detailed the incident from afar, relying on secondhand sources, scraps of information, and rumors. Few people have investigated the event themselves, tracking the laughter all the way to its source. That’s why we’re here.
To be honest, we’re a bit skeptical of the whole account. Uncontrollable laughter, jumping from person to person like a devilish possession, doesn’t make sense. But something happened in Tanganyika in 1962. There are enough firsthand accounts and medical reports to confirm that. But what that something is—and what, if anything, it has to do with humor—is still up for debate.
We’re hoping our time here will provide us with clues about laughter in general, a phenomenon that’s mysterious in itself. We’ve investigated a lot of funny stuff between all that stand-up in Los Angeles and all those cartoons in New York, but the laughs generated by professional comedy are just a fraction of the chuckles, giggles, and titters in our daily lives. Why is that? Why would we have developed this odd vocal mannerism? Why do we have an innate need to vocally share what we find funny with others? And why, come to think about it, do laughter and humor not always go hand in hand? Why did hundreds of people in 1962 East Africa start laughing when nothing was funny at all? And why is laughter so contagious, so compelling, that it can act like an out-of-control disease?
It began with three schoolgirls.
On January 30, 1962, at a mission-run girls’ boarding school in Kashasha village not far from Lake Victoria, three schoolgirls “commenced to act in an abnormal manner.” That’s how it’s described in a 1963 Central African Journal of Medicine article titled “An Epidemic of Laughing in the Bukoba District of Tanganyika,” the most authoritative account of the incident. More specifically, according to its authors, local medical officers A. M. Rankin and P. J. Philip, sudden and repeated bouts of laughing and crying seized the girls. The phenomenon soon spread to their classmates. The attacks would last for a few minutes to a few hours, and one poor girl reportedly experienced symptoms for sixteen straight days. Victims couldn’t focus on their schoolwork and would lash out if others tried to restrain them. They claimed things were moving about in their heads, that somebody was out to get them.
By March 18 of that year, 95 of the school’s 159 middle and high school girls had been affected. At that point, to temper the ailment’s spread, the school shut down. It reopened on May 21, only to close again when dozens more came down with symptoms. By that point, the epidemic had spread beyond the school.
Kashasha seems as good a place as any to start our investigation, so on our first full day in Tanzania, we head to the village, a small community on a forested ridge overlooking a sweeping, misty valley. Right off the main road we find the school, still in operation, though it hasn’t housed a girls’ school in decades. Now it’s a vocational school. Classes aren’t in session on this overcast, drizzly day, so the campus’s small grassy yards are empty, and the shuttered doors to the tinsmith workshop and masonry store creak in the wind. But out of the rain, in the school’s small office, we find principal Jason Kamala, a stocky man in a casual green shirt. “I have heard much about the big laughter you are after,” he declares in accented English, letting loose with a hearty laugh of his own. He gives us a tour of the tidy but timeworn property, recounting what he knows. He’s told this tale before.
The girls’ school, run by German missionaries, was a model institution, he tells us, one of the first boarding schools in the area. Still, says Kamala, life under the school’s strict religious rules wasn’t easy. He shows us the former dormitory, a long, weather-beaten building that now houses carpentry and welding workshops. When this was a boarding school, he says, there were no windows on the sides of the building facing toward the village, “so they would not see boys and men on the road.” Similarly, students weren’t allowed to use the latrine at night because it was too close to the exterior fence.
Kamala takes us to a classroom on a far corner of the property, a basic affair with cracked walls and broken windows. He points to the wooden chairs inside. They are the same as the ones used in 1962, and they are tremendously uncomfortable. The chair backs pitch forward at an awkward angle to promote proper posture—or, as Kamala puts it, to make “good-shaped girls.”
The three girls who started it all were sitting in this classroom when they burst out laughing and couldn’t stop. Bewildered, the teacher rang her school bell, sending the students into the yard outside to calm everyone down. Tracing the students’ path, Kamala positions himself in the yard. Here, he says, other pupils looked at the laughing trio and began cackling themselves. The lawn was soon full of out-of-control cackles. “They laughed and laughed and laughed,” says Kamala.
William Rutta, the Tanzanian guide we’ve hired to accompany us in East Africa, is listening in his fashionable brown sports coat, scribbling away in a small notebook. When I’d first e-mailed him about being our guide, Rutta, the owner of a local safari and tourism company called Kiroyera Tours, had assured me he knew all about omuneepo, the local word for the laughing disease. But now that we’re here, it’s obvious this information is as new for him as it is for us.
But that’s okay. As Rutta would say, “Hakuna matata”—Swahili for “no worries.” The local phrase, made famous by its use in the Disney film The Lion King, is Rutta’s favorite saying, at least when he’s escorting mzungus—white people—like us. Everything so far on our trip can been summed up by “hakuna matata.” In Uganda, when Rutta picked us up at the airport, the country was in the midst of a mid-level crisis that had led soldiers to fire into crowds of angry protestors? Hakuna matata. That the road between Uganda and Tanzania was being built as we drove along it, leading to hours of stopped traffic punctuated by high-speed dashes through heavy machinery and construction craters? Hakuna matata. That when we tried to cross into Tanzania, the Ugandan border-patrol office was empty, with a sign at the window saying everybody was out to lunch for an indeterminate amount of time? Hakuna matata.
Continuing his tour of the school grounds, Kamala tells us that while he wasn’t at the boarding school in 1962, he witnessed omuneepo himself—here, at the vocational school, in 1981. “It happened with three boys,” he says. “They were looking at you like this”—Kamala stares at us, wide-eyed—“then they started laughing: ‘Ha ha ha ha!’ Then you found tears coming. And these boys were so stiff, their whole bodies were so tough. We had to tie them in ropes and put them on mattresses until they recovered.” He’s heard of other cases, too. Every few years a new report of omuneepo pops up at some school or village in the region. Some are just a few years old.
As for what causes these incidents? Kamala just shrugs. “Maybe those who laugh have an element of madness coming into their brains.”
There is something almost akin to madness in how and when we laugh. It’s not as simple as a basic reaction to something funny. Oftentimes we don’t laugh when we come across something humorous, like how all those witty New Yorker cartoons we considered in New York left us with appreciative smiles. And laughter sometimes comes when nothing is funny at all. Type “uncontrollable laughter” into YouTube and you’ll find clips of newscasters cracking up for no apparent reason in the middle of stories about war zones and political scandals. There’s nothing humorous about these moments. Their jobs could be on the line, but they can’t stop cracking up.
No one has illustrated laughter’s strange tendencies better than Robert Provine, a neuroscientist and psychology professor at the University of Maryland, Baltimore County. A few years ago, Provine took a look at the current state of laughter research and wasn’t impressed. “People had been struggling with explaining laughter for thousands of years. I thought it was time to try something else,” Provine told me. “I wanted to do something that would get me into empirical science and away from essay writing.” So Provine engaged in what he called “sidewalk neuroscience,” tracking and observing real-world laughter. He and his collaborators used tape recorders to capture more than a thousand “laugh episodes” in bars and shopping malls and cocktail parties and class reunions. And he had dozens of student volunteers note in a “laugh log” the circumstances around every time they tittered, chuckled, or guffawed.
His findings, detailed in his book Laughter: A Scientific Investigation, were surprising, even to Provine. Fewer than 20 percent of the real-world laughter incidents he catalogued were in response to anything resembling something funny. Far more often, people were giggling or chuckling at innocuous statements such as “I’ll see you guys later,” “I see your point,” and “Look, it’s Andre!” Not only that, but in all these cases, the person who produced the laugh-provoking statement was 46 percent more likely to be the one chuckling than the person listening. And while laughter might seem like something that can erupt at any point in response to something funny, in only eight of the 1,200 laugh episodes did the laughter interrupt what somebody was saying. Instead, in 99.9 percent of the time, laughter occurred in tidy, natural breaks in the conversation, punctuating the speech like a period or exclamation point.1
Provine concluded that the laughter of our everyday lives wasn’t for the most part a by-product of anything resembling jokes. Instead most of it occurs in the give-and-take we have with others that in hindsight doesn’t seem funny at all. This finding puts the challenge of being a professional comedian in a whole new light. A comic is physically removed from the audience; he or she is talking at them, not with them, and for the most part isn’t supposed to laugh during the routine. Comedians are essentially trying to score laughs in the exact opposite way that most people do. Now, we don’t believe it’s time to reinvent stand-up along the lines of everyday conversations. As we learned the hard way, chatting one-on-one with Louis C.K. is far from a hilarious experience.
Pete thinks the benign violation theory might play a role in Provine’s unusual findings. The seemingly unfunny bits of dialogue that triggered most bouts of laughter might still be benign violations, says Pete—just violations that are so benign they’re only laughable when you’re right there, in the moment. It’s the ultimate version of “you had to be there.”2 Whether or not this is the case, Provine’s discoveries suggest that laughter is inherently social, that at its core it’s a form of communication. Sure enough, when Provine went through the laughter logs he’d collected, he found his participants were 30 times more likely to laugh in the presence of others than when they were alone. Among the few solitary instances of laughter, nearly all occurred in response to TV shows or other media—in short, electronic proxies for other people. When people were truly alone, laughter all but disappeared.3
Provine found one other piece of evidence that he believed demonstrated laughter’s social power, one other bit of proof that suggested laughter’s communal sway was far more dramatic than most people realize. As he noted in an article in American Scientist, “The Tanganyikan laughter epidemic is a dramatic example of the infectious power of laughter.”
Is he right? Was what started here 50-odd years ago in this boarding school an instance of laughter’s social power gone haywire? We have more investigating to do.
The town of Bukoba, the administrative center of this corner of Tanzania and our base of operations, lies on the western shore of Lake Victoria, the world’s second-largest freshwater lake. It’s a beautiful spot: verdant tropical hills on one side, an endless expanse of blue on the other. It’s like an African version of a Mediterranean seaside town, albeit one with bumpy dirt roads, corrugated metal roofs, and the smell of burning trash lingering in the breeze. Our accommodations, on a palm frond–dotted rise overlooking the town, bills itself as “the only luxurious tourist hotel” in the region, although “luxurious” is up to interpretation. There are enough mosquitoes buzzing about to inspire us to pop antimalarial pills like Tic Tacs, and there’s at least one room—mine—that doesn’t have hot water. (Eventually I get a new room, but then I’m confronted with the opposite problem: a shower that only scalds.)
Bukoba, when we wander about it, exudes an easygoing backcountry feel, a community-wide version of our guide Rutta’s “hakuna matata” mentality. This makes sense, considering it’s about as far from Tanzania’s capital, Dar es Salaam, as you can get. In a place like this, we figure something as disruptive as a laughter epidemic should be easy for folks to recall.
Luckily, we’re traveling with somebody who knows everybody. Rutta, who lives in Bukoba, has a copy of Dale Carnegie’s How to Win Friends and Influence People in his van’s center console, and he’s been putting the self-help book to good use. He has two cell phones, one or both of which is always going off. It’s difficult to make it across town with him in a timely fashion, since he’s always stopping to say hello to somebody. “You’re like the mayor!” exclaims Pete. Rutta just chuckles as he answers a call.
But in and around Bukoba, even with the unofficial mayor’s help, people don’t have much to offer regarding omuneepo. “All I can say is, it was sort of a miracle,” a former school administrator who witnessed some of the cases tells us with a shrug. It was a supernatural phenomenon, counters an elderly Muslim cleric we meet later. He believes it was spirits of people’s ancestors causing trouble. Local education and medical officials aren’t much help, either. The incident occurred in Kashasha half a century ago, they say—why are we bothering about it now? Plus, they add, are we sure we have the right Kashasha? There’s another Kashasha, they tell us, far away from here, in a part of the country that’s not their problem. Maybe we should go there, they suggest, insinuating it might be best if we don’t come back.
People around here clearly have far more pressing things to worry about, like typhoid and malaria and illiteracy and AIDS, than a bad case of the laughs. To be sure, excessive laughing can be a sign that something is wrong with you. Pathological laughter, when nothing is funny at all, can be a symptom of all sorts of unpleasantness: Parkinson’s Disease. Multiple sclerosis. Pseudobulbar palsy. Alzheimer’s. Certain kinds of schizophrenia. Aftereffects of a pre-frontal lobotomy. A type of brain tumor called hypothalamic hamartoma that triggers “gelastic epilepsy.” Angelman syndrome, formerly known as “happy puppet syndrome,” since the people who have it act like the jolly playthings of some invisible puppeteer. Kuru, or “the laughing sickness,” an incurable and deadly brain disorder that once swept through the highlands of Papua New Guinea, believed to be triggered by locals consuming their dead relatives.4
But the laughter episodes here in Tanzania don’t seem to have anything to do with these ailments. A. M. Rankin and P. J. Philip, the doctors who wrote about the situation in the Central African Journal of Medicine in 1963, tested for infections, viruses, food poisoning, and waterborne diseases. They found nothing.5 Plus, in many of these other conditions, uncontrollable laughter leads to far more serious side effects. In Tanzania, the laughter just led to more laughter. Or as Rankin and Philip put it, rather dryly, “No fatal cases have been reported.”
One evening, maybe to make up for all the dead ends in Bukoba, Rutta takes us for a night on the town. He directs us into the dark, smoky back room of a downtown Bukoba bar where, on a cleared-out space in the center of the floor, women take turns dancing to African pop songs in skimpy outfits and heels. The place reeks of grilled meat, courtesy of a closet-like kitchen in the corner, where a sweat-drenched cook is churning out endless plastic trays heaped with charred flesh. In between musical numbers, the women hurry behind a curtain hanging from the back wall and reappear a few moments later in a full costume change. At one point, a dancer emerges in a plaid shirt and cowboy boots and performs a country line dance to Dolly Parton’s “Coat of Many Colors.” The operation resembles a chaste if still misogynistic version of an American strip club. And eventually, to spice it up, the women decide to make the only two mzungus here part of the show. So one by one, Pete and I get pulled into the spotlight.
That’s how we find ourselves on stage at an African burlesque show, staring at a room of frowning men gnawing on blackened animal pieces and wondering what the hell we’re doing up here, blocking their view. And so we dance. Pete waltzes with one of the dancers like he’s Al Pacino in Scent of a Woman. I play coy with the ladies on stage and shake my butt at the audience. Pete trots out “the lasso,” twirling an invisible rope and using it to capture one of the dancers. All for the sake of science.
We return to our seats amid the sounds of chuckles and claps. We weren’t the sexiest dancers to grace the stage, but we were the funniest. And that has to count for something, since humor wouldn’t have evolved in humans if it wasn’t appealing from a sexual-selection standpoint—if it weren’t, at some level, “sexy.”
Sure enough, a survey of 700 men and women discovered that people considered humor among the most important of all characteristics when choosing a partner, romantic or otherwise.6 And studies of happy marriages, especially those lasting more than a half century, find spouses often ascribe their marital bliss in part to laughing together.7 This finding makes sense, says Pete: if you and your partner can make each other laugh, that suggests you have a similar sense of humor and therefore share compatible values, beliefs, and interests. Plus you’re both adept at making the other person happy.
Unfortunately, research also suggests the opposite: humor can signal doom for a relationship. Studies have found that dating couples who exhibit strong senses of humor—and not mean-spirited humor, mind you, but positive and friendly humor—are more likely than others to break up. As paradoxical as that sounds, it’s not absurd. Since humor is such a highly regarded personal trait, it’s more likely that others will be enticed by these attractively funny people and will lure them away from their partners.8
But what, exactly, is evolutionarily attractive about a sense of humor? What use from a survival-of-the-species perspective is the ability to recognize what’s funny and then bark about it? Some evolutionary theorists have posited that humor must have developed to demonstrate intelligence and creativity through wit, while others see laughter as a vocal adaptation of social grooming, a way to build bonds with one another without having to pick critters off each other’s hides. The list of theories goes on: laughter could have been a “disabling mechanism,” a way to signal that poking that crocodile with a stick is so laughable it might threaten our genetic survival. Or it could have been a way to determine winners and losers on the social strata—differentiating between those who deserve to laugh at others and those who deserve to get laughed at without resorting to prehistoric gladiator battles.9 Or it could have been a signal of false alarm, a vocal demonstration that the rustling in the bushes wasn’t a saber-toothed tiger as expected, just a harmless antelope.10 One of the newest theories suggests that laughter could be the brain’s version of an error message, that it evolved as a way for the mind to notice, reward the discovery of, and verbally signal mistaken leaps to conclusion.11
All these ideas are compelling in their own ways, but most lack hard evidence to verify their claims. If Pete were a betting man, he’d put his money on an idea put forward in 2005 by an undergrad named Matthew Gervais and his advisor, evolutionary biologist David Sloan Wilson, at Binghamton University in New York. In 29 heady pages in the Quarterly Review of Biology, the two wove together findings from neuroscience and positive psychology and multilevel selection theory to synthesize a novel and compelling account of how and why we developed the ability to laugh. It’s the sort of virtuoso academic performance that makes a science geek like Pete gush, “That paper is amazing.”
What’s possibly most intriguing of all about their theory is that its key piece of evidence originated, of all places, from the work of a quirky nineteenth-century fellow named Guillaume Duchenne, a guy who went around zapping people’s faces with electrodes. Duchenne, a French physician, became obsessed with figuring out what happened to human bodies when he shocked them with the hot new gizmo of the time: a portable battery and induction cable. Luckily for him, he worked at a women’s hospice, so he had access to a lot of prone bodies to zap. He must have been quite the charmer. All the ladies wanted to be electrocuted by the “little old man with his mischief box.”
Applying the prongs of his mischief box to people’s faces, Duchenne evoked and captured one kind of smiling—the voluntary kind, the type of expression we produce when we grin or chortle to be polite. This mannerism, he discovered, involves the face’s zygomatic major muscles raising the corners of the mouth. But Duchenne discovered there was a second variety of smiling and laughing, one that occurs when we find something truly entertaining or funny. This expression was more complex, utilizing both the zygomatic major muscles and the orbicularis oculi muscles that form crow’s feet. It’s why people say a real smile is in the eyes. Duchenne was never able to reproduce with his electrodes this second form of expression, now known as a Duchenne smile or Duchenne laughter, and he came to believe it was “only put at play by the sweet emotion of the soul.” It was one of many scientific discoveries by the erstwhile electrocutioner, though Duchenne might have taken things too far in his book The Mechanism of Human Physiognomy. He had a beautiful model pose as Lady Macbeth while he zapped her face into different theatrical expressions.12
More than a century later, Gervais and Wilson saw Duchenne’s discovery as evidence that laughter evolved at two different points in human development. First, they posited, at a point sometime between 2 and 4 million years ago came Duchenne laughter, the kind triggered by something funny. An outgrowth of the breathy panting emitted by primates during play fighting, it likely appeared before the emergence of language. This sort of laughter was a signal that things at the moment were okay, that danger was low and basic needs were met, and now was as good a time as any to explore, to play, to start laying the social groundwork that would lead to civilization. And this part of laughter’s evolution could tie with Pete’s idea that humor is elicited by benign violations, said Gervais, now a doctoral candidate in biological anthropology at UCLA. “There could be a violation or incongruity of expectation going on, but what’s being signaled by the laughter is that it’s not serious, or it’s benign,” Gervais told me. “What the humor is indexing and the laughter is signaling is, ‘This is an opportunity for learning.’ It signals this is a non-serious novelty, and recruits others to play with and explore cognitively, emotionally, and socially the implications of this novelty.
“I think it’s an important part of the human story that humans are learners,” he continued. “And something like an appreciation of humor is a process that encouraged exploration and learning for a species that has a brain built to learn.”
But then, sometime between 2 million years ago and the present, theorized Gervais and Wilson, the other sort of laughter emerged—the non-Duchenne sort, the kind that isn’t dependent on something being funny. As people developed cognitively and behaviorally, they learned to mimic the spontaneous behavior of laughter to take advantage of its effects. They couldn’t get it right—they couldn’t simulate the eye-muscle movements of real laughter and smiling—but it was close. It’s similar to the way some moths evolved “owl eye” patterns on their wings to scare away predators—but in the case of non-Duchenne laughter, the point wasn’t to scare away, it was to bring others closer. Mimicked laughter was a way to manipulate others, to hot wire their vulnerability to be entertained—sometimes for mutually beneficial purposes, sometimes for more devious reasons. As Gervais and Wilson put it in their paper, “non-Duchenne laughter came to occur in aggressive, nervous, or hierarchical contexts, functioning to signal, to appease, to manipulate, to deride, or to subvert.”13
It’s a compelling, if not the most cheerful, account of why we laugh. If Gervais and Wilson are right, what about the laughs we inspired at the African strip club? Were the chuckles the old kind, the involuntarily stuff of genuine amusement? Or the non-Duchenne, darker version—laughter meant to appease, or worse still, to deride? I’m hoping for the former, but I have a feeling it might be the latter.
Since we’re in Africa, we figure we ought to go on a safari. Rutta is happy to oblige, one morning aiming the van toward Rubondo Island National Park, a 176-square-mile nature preserve off the coast of Lake Victoria. As we zoom up and down the rolling green hills skirting the lake, Pete fires up some Tupac Shakur on his iPod. “In the citaaay, the city of Compton!” sings Rutta, a big hip-hop fan, as we blow past longhorn cattle and vervet monkeys scampering about on the side of the road. “You know,” Rutta says to Pete, “most professors don’t act like you.”
“Thank you,” says Pete.
We eventually stop at a small, mud-bedraggled port, where we charter a small red-and-white motorboat to take us across a thin strait to Rubondo Island. Two somber-faced men in gray parkas sit behind us in the boat, armed with sizable old machine guns. We decide not to ask what threat, human or animal, necessitates that kind of firepower. When we reach the island, a four-wheel-drive safari jeep takes us through its densely forested interior. As we rumble down a two-track dirt road, foliage whipping at the windows and overhead vines sliding along the roof, I eye Rutta’s stylish camouflage shirt-and-pants combo and safari vest. As usual, he’s dressed for this excursion far better than we are.
We hope to spot some of the chimpanzees that inhabit the island, maybe even get a chance to tickle them. As we’ve noted, it’s believed that human laughter evolved from the distinctive panting emitted by our great-ape relatives during rough-and-tumble play to signal it’s all in good fun and nobody’s about to tear anybody else’s throat out. In a clever bit of scientific detective work, psychologist Marina Davila-Ross of the University of Portsmouth in the United Kingdom digitally analyzed recordings of tickle-induced panting from chimps, bonobos, gorillas, and orangutans, as well as human laughter, and found the vocal similarities between the species matched their evolutionary relationships. Chimps and bonobos, our closest relatives, boasted the most laughter-like kind of panting, while the noises of gorillas, further down our family tree, sounded less like laughing. Orangutans, our truly distant ancestors, panted in the most primitive way of all.14
Even if we don’t find one of our hairy relations out here in the jungle, maybe we can at least find a rat or two and tickle them. There are scientific antecedents to support such a venture. In 1997, psychologist Jaak Panksepp entered his lab at Bowling Green State University in Ohio and told undergrad Jeffrey Burgdorf, “Let’s go tickle some rats.” The two and their colleagues had already discovered that lab rats emitted a unique ultrasonic chirp in the 50-kilohertz range when they played. Now they wondered if they could prompt these squeaks through tickling. Sure enough, when the researchers began poking at the bellies of the rats in their lab, their ultrasonic recording devices picked up the same 50-kilohertz sounds. The rats eagerly nestled their fingers for more. Soon, as the news media trumpeted the existence of rat laughter, people the world over were opening up their rat cages and engaging Pinky and Mr. Pickles in full-scale tickle wars.15
“I don’t necessarily call it laughter; I call it a signal of positive affect,” Burgdorf told us when we visited him at Northwestern University’s Falk Center for Molecular Therapeutics in Chicago, where he now works as a biomedical engineering professor. Burgdorf’s careful choice of words makes sense. He and Panksepp faced serious critical pushback when their rat-tickling activities first went public. But whatever you want to call it, Burgdorf, a quick-witted guy with a boyish face and a sign on his office door that reads “Know-It-All,” has been obsessed with that strange rat noise he first stimulated in 1997. “How do I know that it’s really a sign of positive affect?” he said to us. “That’s been the question of my career.”
So far, it seems he’s on to something. He found the 50-kilohertz chirping changed when one of the animals involved in rough-and-tumble play was much larger than the other, when it was no longer fun and games and instead outright bullying—or as Pete would say, when the physical violations were no longer benign. And when given a choice, Burgdorf’s rats would push a bar to play a recording of the 50-kilohertz chirp as opposed to other rat noises, suggesting they had a preference for the sound. Finally, when Burgdorf and his colleagues used electrodes, opiates, and other manipulations to stimulate the reward centers of rats’ brains, the rats produced that same laughter-like noise.
And now, here in this lab, with its key-card-required security doors and freezers of bio samples and warning signs for radioactive materials, Burgdorf is using his rats and their special squeaks to test a new depression medication designed to increase positive mood. Clinical trials are already in phase two, and if all goes well, the drug might hit the shelves in three or four years. That’s right: Big Pharma is using laughing rats to develop a happy pill.
Tickle-loving rats, joke-playing gorillas, even stories of dog laughter—these reports could just be the beginning, said Marc Bekoff when we met him at a coffee shop in Boulder, Colorado. Bekoff, a colleague of Pete’s at the University of Colorado, where he’s a professor emeritus of ecology and evolutionary biology, is one of the world’s foremost experts on animal emotions. And he, for one, believes we’re on the cusp of discovering that lots of animals have a sense of humor, maybe even all mammals. He pointed to Darwin’s idea that the difference between human and animal intelligence is a matter of degree, not of kind. Or as Bekoff put it, “If we have a sense of humor, then non-human animals should have a sense of humor, too.” Considering the groundbreaking discoveries that ethologists like Bekoff are making about animal behavior, from dogs understanding unfairness to baby spiders displaying different temperaments to bees being taught to be pessimistic, the idea of thousands of inherently funny species might not be all that far-fetched.
Unfortunately, cruising through the wild kingdom of Rubondo Island in our safari jeep, we don’t spot any chimps, rats, dogs, or other animals to tickle. So we park the vehicle by a guesthouse near the water, and Rutta suggests the three of us go bushwhacking. We set off into the woods, climbing over tree trunks and pushing through foliage, hot on the trail of . . . well, anything at all safari-worthy. Along the way, Rutta points out a heaping pile of elephant dung, which Pete nearly steps in. Then Pete tries swinging Tarzan-style from a hanging vine, and somehow doesn’t end up killing himself. After that, Rutta guides us to a shallow cave in a cliffside he’s visited before, pointing out a collection of bones scattered about its floor. “Dead people,” he explains, remnants of a time when foreigners like us weren’t so welcome on the island. Now I’m starting to wonder about those rifles our escorts brought along.
“If I don’t almost get eaten, I will be disappointed,” declares Pete as we tromp through the underbrush. A few minutes later, I feel a stinging pain on my leg, then another. Looking down, I find black soldier ants swarming my feet and legs, crawling into my shoes and under my socks and biting hard any time they come across skin. Pete’s covered in them, too. We slap at our legs, cursing in pain as the little buggers make a meal of our calves. Meanwhile Rutta, diligent safari guide that he is, pulls out his camera and starts taking photos of our misery.
Our walk in the jungle a bust, we return to the guesthouse and try a different tack: we pay the pilot of a small dinghy moored by the shore to take us around the island’s shoreline. Motoring along the coast, we find wildlife: cormorants and egrets and ibis perched by the shore, African fish eagles swooping overhead, hippo snouts bobbing among the waves, and giant crocodiles slipping into the greenish water as we cruise by. Off in the distance, we glimpse a freakish sight: gigantic black clouds rising from the water’s surface, as if the lake were on fire. These are African lake flies, explains Rutta, hatching by the millions. But then our pilot notices another kind of cloud forming overhead—storm clouds.
He turns the boat around and heads back, but he’s not fast enough to outrun the storm. The wind whips up, and rain begins pelting our faces. The pilot guns the outboard motor, but that just sends more water sloshing into the boat. The rain beats down harder and harder, and soon we’re plowing through an endless gray curtain of water. “These are three-foot, four-foot swells!” hollers Pete over the engine as the dinghy rocks wildly back and forth in the waves. Suddenly, in the midst of our soggy misery, I start laughing. Maybe it’s the absurdity of the situation, or maybe I’m going insane with fear. Either way, Pete joins in, and Rutta does, too. Here we are, facing a possible watery grave in the middle of Lake Victoria, and we’re cackling like maniacs. And we can’t seem to stop.
We make it back to shore just as the squall moves on. As the sun reemerges from the clouds, we strip to our pants and lay out our waterlogged clothes out on the shore to dry. “I was thinking, ‘Is this a good thing or a bad thing?’ until I heard you laugh,” Pete tells me as we stretch out in the sun, his iPod blasting more 1990s hip-hop. “It’s an example of how laughter signals things are okay.”
Rutta has another interpretation. “It’s omuneepo!” he declares, nodding his head to Biggie Smalls.
When the Kashasha boarding school shut down during the laughter outbreak in 1962, the schoolgirls went home—and along with them went omuneepo. At Rwamishenye girls’ middle school just outside Bukoba, a third of the 154 pupils came down with symptoms after several of the Kashasha students returned to their homes nearby. That school closed, too, and one of the pupils from that institution returned to her village twenty miles away, where she spread the ailment to her family, including a relative who’d walked ten miles to witness the symptoms. Soon two boys’ schools nearby were overrun and shut down, too. “At the time of writing this paper the disease is spreading to other villages, the education of the children is being seriously interfered with, and there is considerable fear among the village communities,” noted Rankin and Philip in their Central African Journal of Medicine article. There’s no indication when, exactly, the laughing finally stopped or how many people were affected, but some reports put the total at approximately 1,000 victims.
No community suffered as much as Nshamba, a village southwest of Bukoba. There, according to Rankin and Philip, 217 villagers came down with the ailment after several of the Kashasha schoolgirls returned to their area homes. So, on a rainy African morning with gray clouds hanging low overhead, we roll into Nshamba, a busy community crisscrossed by red dirt roads.
Since many of the victims were young women, we head off in search of female villagers. We find a group in front of a coffee co-op, kneeling on a tarp and sorting by hand through large mounds of green coffee beans, looking for runts. Yes, they tell us through Rutta, they know of the laughing disease. One of them even suffered from it: the woman in the corner in the brown hairnet. We’re eager to hear more, but the women turn back to their work, ignoring us. We’re flummoxed, until Rutta explains that they’re thirsty. They could use some sodas.
We catch on. Pete wanders over to a local shop and returns with a crate of Pepsis, Fantas, and Sprites. The women cheer. Once they’ve cracked open their soda-pop bribes with their teeth, they are eager to chat. We sit down with the woman in the brown hairnet, who tells us she came down with the disease in July 1996. She felt a pain in her back and head and then, three days later, lost control of her body—laughing, crying, speaking in strange languages. Only when she was taken to the hospital and given a shot of quinine did she recover.
This wasn’t omuneepo, says Rutta. It was cerebral malaria. His second brother came down with it, causing him to run around like a maniac until he collapsed in exhaustion.
Our search through the town continues, past free-range chickens scurrying about and women eyeing us from doorsteps, chewing bits of sugarcane. We learn that the person we should talk to is a woman named Amelia. We’re told she was the first person in Nshamba to come down with the ailment once it was brought here by the schoolgirls. When she recovered she became a healer, treating others with the disease. There’s only one problem: Amelia now lives far away from here, we’re told, in a distant part of the region. And she’s crazy.
Meanwhile, children have been gathering about us, drawn by the spectacle of the two white guys, apparently not a common sight. As we make our way back to the van, they break out in singing: “Mzungu, eh, eh, eh! Mzungu, eh, eh, eh!” Whether the song’s making fun of us or not, Pete joins in the festivities, jumping about wildly as the small children laugh with glee.
These children, as young as they are, see the humor in what’s going on here: two mzungus, out of their element, dancing about like maniacs. Laughter develops in infants far earlier than language, usually between just ten and twenty weeks of age. (Aristotle was off when he declared babies begin laughing on their fortieth day.) To be clear, what these babies are laughing at isn’t humor as we understand it; they just find certain stimuli pleasurable. (For those stuck alone with their baby nephew without any idea of what to do with him, take note: according to observational studies of what 150 infants in the first year of life laughed at, kissing the kiddo’s tummy and playing “I’m gonna get you!” are winners. Bouncing the tyke on your knee? Not so much—nor is it very safe.)16
According to Paul McGhee, who has spent years studying how humor develops, children don’t begin to recognize things as funny until about halfway through age two. That’s when they understand that objects have meanings that can be rearranged in funny ways (like using a banana like a telephone). But that’s not the end of it. According to McGhee, there are still three other developmental humor stages to come. Early in their third year, kids typically start using their developing language skills to mislabel objects, similar to the way I still inanely point to horses I see on long car trips and call them cows, just to piss off my wife, Emily. Then soon after, children grasp conceptual humor, based on the idea that objects have attributes that can be rearranged in an amusing fashion. And by this point, these kids are laughing all the time. Studies of five-year-olds have shown they laugh, on average, 7.7 times per hour, while the average American adult laughs just eighteen times a day.17
At around seven years, children develop the ability to juggle multiple concepts and meanings in their minds at once, so they finally get the whole shebang: plays on words, double meanings, puns, and complicated jokes.18 Still, children often need several more years under their belts before they fully get the joke behind tricky concepts like irony and satire. That’s not too surprising, considering that sarcasm is often so difficult to grasp, even for adults, that there are efforts afoot to create new forms of punctuation to indicate it. That includes the SarcMark, which looks like an upside-down “e” with an eyeball. This, to us, is a great idea. 
As obvious outsiders in Nshamba, it’s to our advantage to joke and laugh not just with these kids, but with grown-ups here, too. That’s because laughter and humor are powerful social signals, indicating to the world in big, bold letters that things are okay. As sociologist Rose Coser once put it, “Laughter and humor are indeed like an invitation, be it an invitation for dinner, or an invitation to start a conversation: it aims at decreasing social distance.” Humor and laughing are so good at this, so adept at increasing positive feelings and social intimacy, that they seem to operate like a remote control, with someone else’s mind as your personal boob tube. A few years ago, researchers in London had people listen to laughter while an fMRI scanner monitored their brain response. They found that just the sound of chuckling, without any humor at all, was enough to trigger neurons in the part of the brain that controls the muscles for smiling and laughing. Scientists have labeled these cells “mirror neurons,” since they mirror the behavior being observed. Negative sounds, such as screaming and retching, also activated corresponding mirror neurons, but at a weaker level.19
No wonder the crews of professional laughers we auditioned for in Los Angeles are in such high demand to help get sitcom audiences chuckling. Here was more scientific proof that laughter really is contagious.
But when you joke or laugh, you do more than just make those around you prone to laughter, too. Because humor helps you come off as less threatening and more socially attractive, it can help convince others, in an almost voodoo-like way, of all sorts of unreasonable things. In one study, people trying to bargain down the price of a landscape painting were willing to accept a higher cost if the person on the other side of the negotiating table cracked, “I’ll throw in my pet frog.”20 In another experiment, people listened to a speech that had been intentionally disorganized, with nearly a third of all sentences rearranged randomly. Those who heard a version that included jokes throughout the discourse rated it more organized than its equally muddled counterpart.21 So now, if we can use humor to convince people in Nshamba that we, a couple of white guys asking odd questions about some half-forgotten mysterious ailment, aren’t up to no good? All the better.
Discussing our options with Rutta, we decide our best bet is to try to track down this woman Amelia. So we pile into the van, which we’ve renamed the “Hotbox” because of its lack of air-conditioning, and head off into the bush. Deeper and deeper we drive into the backcountry, past verdant stands of banana trees and through rocky, remote valleys. The rain clouds have passed, and the hot African sun beats down on the van. “Welcome to Tanzania,” Rutta cracks as we inch down a treacherous series of switchbacks, the rock-strewn dirt road nearly tearing out our transmission. Every now and then, we come across somebody ambling down the road, and Rutta pauses to ask directions. More often than not, these passersby climb into the vehicle to show us the way. Soon we have the equivalent of a small village crammed into the van, all of whom profess to know where Amelia lives.
The dirt roads soon regress to little more than rugged trails, spindly tree branches scraping against the sides of the van. “This is the end of the road,” announces Rutta, parking at the end of a dusty footpath flanked by rugged fences of tied-together sticks. At the end of the path, we find an elderly woman in a faded shirt and skirt working in a meager field. She regards us, frowning, and shuffles on bare feet over to a small, mud-walled shack. We follow her inside and sit on the ground in the murky, fragrant interior. Yes, she says, her name is Amelia. Yes, she’s from Nshamba. Her dark eyes fix on Rutta alone, hardly acknowledging Pete’s and my presence at all. Her white hair frames a rigid grimace.
Then Rutta mentions omuneepo. Amelia flinches, startled. “Omuneepo?” she asks, leaning forward. But the moment passes. Her poker face returns. “I don’t know anything about that,” she tells Rutta in Swahili. Rutta doesn’t buy it, pushing her to say more. Fine, she relents. Maybe she had the disease once, as a young woman. “But that was 60 years ago,” she grumbles. She doesn’t remember anything about it.
But what about what happened after? prompts Rutta. Didn’t she treat people with omuneepo? Yes, she admits, she treated sick people. But she can’t recall what she treated them for. We sit there, dumbfounded, as flies buzz about our heads. Beams of sunlight slice through the dusty gloom, radiating from holes in the walls.
She’s afraid, Rutta tells us when we step outside for a moment. “In Tanzania, some people are killed if they are practicing witchcraft.”
Undaunted, we press on. “I was eight years old when there was war between Uganda and Tanzania, and I still remember it,” protests Rutta. We explain to her that Pete’s a university professor, that we’ve heard the rumors about omuneepo and we’re eager to hear the truth.
But Amelia just shakes her head, making it clear it’s time for us to go. Whatever she knows about omuneepo, she’s taking it with her to the grave.
Jason Kamala, the principal of the vocational school in Kashasha, recommended we talk to Kroeber Rugeiyamu, Tanzania’s first indigenous psychiatrist. He’s retired now, Kamala told us, and lives not far from the school. So one warm afternoon, we pull up in front of Rugeiyamu’s home, which looks like no other home we’ve seen in Tanzania—or any other house we’ve seen anywhere.
A tall, sloping cone of rock, concrete, and corrugated metal rises from the earth, like an industrial-strength igloo. The house is a modernized version of the region’s traditional woven-grass huts known as mushonge, we learn from Rugeiyamu, a slight, gray-haired man with a wise smile and bright eyes. “My father was content with his mushonge, but I am a medical man,” says Rugeiyamu, guiding us around his property in a remarkably spry manner, considering he was born in 1928. So, for his mushonge, Rugeiyamu mixed the best of both worlds—the traditions of his homeland and the ideas he adopted while studying medicine in Great Britain. The outhouses out back feature subsoil fertilization systems to feed his banana trees and vanilla vines. In the depths of the hut, past the grain storage area and wood-fired ovens, a dusky library overflows with books—the plays of Shakespeare, a biography of Nelson Mandela, a copy of The Rise and Fall of the Third Reich. When the tour is over, Rugeiyamu deposits us in the main room of his mushonge, where, surrounded by soaring concrete pillars and a cathedral-like ceiling, we sit on the straw-covered ground and pass around a gourd filled with pungent fermented wine made by locals crushing bananas with their bare feet.
From his distinctive perspective, from his fusion of the old and the new, Rugeiyamu offers us his take on omuneepo. “It’s hysteria, isn’t it?” he says with a knowing smile, as though this was obvious all along. More specifically, mass hysteria, the spontaneous communal eruption of hysterical symptoms, often a response to stress. According to Rugeiyamu, the Kashasha pupils and other schoolchildren who came down with the laughing disease had lots to be stressed about. “Life was different for the students before they went to school; They had freedom,” he says. “At school, there were strict limits to freedom. And this was a form of expression: the children started laughing. Rather than protesting, they were laughing.”
This makes sense from what we’ve learned. While the Kashasha school sounds far from ghastly, it was clearly not an easy place to go to school, with its windowless dorms and uncomfortable chairs. And since it was one of the first boarding schools of its kind in the region, the schoolgirls were likely unprepared for the religious-based limits on their largely liberated childhoods. As Rugeiyamu suggests, they had reason to protest.
While Rugeiyamu didn’t live in this part of the country and didn’t witness the omuneepo outbreak himself, in later years while working for the ministry of health, he was dispatched to other schools where similar symptoms erupted. And always, he says, he found evidence that something was wrong. Serious overcrowding. Poor food quality. A headmistress who had gone AWOL, leaving the school rudderless. “It’s a form of complaint,” he concludes. “They have no alternative form of expression.”
A few years ago, Christian Hempelmann, a Texas A&M professor of computational linguistics and an avid humor researcher, decided he wasn’t sure about the claim in Provine’s book Laughter: A Scientific Investigation that what happened in Tanganyika in 1962 was an example of the contagiousness of laughter. It just didn’t seem to fit into what we knew about laughter, he told me before our trip. So he scoured the psychological literature available and, in a 2007 article published in HUMOR: The International Journal of Humor Research, he came up with the same conclusion as Rugeiyamu.22
The evidence to support this theory is compelling. Historical surveys of 140-plus outbreaks of mass hysteria between 1872 and 1993 found that half of all cases occurred in schools just like Kashasha, and the majority of the victims were women—young women, in particular.23
And laughter, it turns out, has occurred in other cases of mass hysteria, at least the more physical kind known as motor mass hysteria. I learned this when I called Robert Bartholomew, an Australian sociology professor who’s an expert on UFO scares, witchcraft terrors, dance manias, headhunting panics, imaginary air raids, and other bizarre human behavior.24 “With mass motor hysteria, there have long been reports of laughing that go on for long periods of time intermittently,” Bartholomew told me. From his extensive computer databases, he called up a variety of those reports: The Klikushestvo shouting manias of the beleaguered later years of imperial Russia. Outbreaks in strict primary schools in turn-of-the-century Europe. Occurrences amid substandard factory conditions in twentieth-century Singapore. Bouts in a down-and-out Canadian sardine packing plant in 1992. Incidents among Nepalese schoolgirls in 2003. In all these cases, said Bartholomew, “the common denominator was they were under, without a doubt, extreme stress.”
The fantastical symptoms of omuneepo and other communal manias might seem like something from an exotic time and place. And, sure enough, mass motor hysteria is less common in more modern parts of the world. But that doesn’t mean what happened in Tanganyika can’t still happen right in our own backyard.
“Have you heard about this thing going on right now in Le Roy?” Latif Nasser, a Harvard grad student researching omuneepo, asked me when I gave him a call. He’s referring to the news that in the New York factory town of Le Roy, high school students were coming down left and right with uncontrollable tics, wild gestures, and crazed outbursts. As in Tanzania, the ailment was primarily striking young women, spreading outward from the most popular in school like some shared secret passing from one girl to the next. Some experts were suggesting mass motor hysteria, possibly due to the stress of growing up in a dead-end town. But many parents rejected the diagnosis, looking for some other cause. Erin Brockovich, the famous environmental legal crusader, even investigated whether the shuttered factories had left behind something horrible in the streams and fields.25 She didn’t find anything.
It’s the same way as how people here in Tanzania have shirked our questions, or blamed the strange laughter on witchcraft or dead relatives or the unknowable hand of God. It’s sometimes easier to ignore these episodes, or look for a culprit, than to accept them for what they are: a collective cry for help.
On our last day in Tanzania, Rutta remembers something. He’s heard rumors that at a nearby school, kids had been acting strangely. He suggests we check it out, hopping in the van with more haste and eagerness than we’ve seen all trip. Maybe our obsessive-compulsive tendencies are rubbing off.
The school’s principal, a matronly woman in a pink pantsuit named Margaret Shilimpaka, greets us when we arrive. She tells us the co-ed school recently updated its curriculum from home economics to more contemporary, practical skills like hospitality training and food services. Looking around the scattering of modern buildings on a grassy knoll, it’s hard to conceive anything majorly wrong here. But yes, Shilimpaka tells us, her students have been losing control. “There are many,” she declares, eyes widening for emphasis. “They start laughing, crying, ‘I like this, I don’t like this.’ ” She shakes her head. The last two years, she says, have been “very, very bad.”
We ask to see some of the victims, and she has a teacher fetch the most serious cases. They return with four girls and one boy, all with short-cropped hair and matching gray-and-white school uniforms. They sit quietly, eyeing us curiously, looking like typical high school students. But they’re not, they tell us; something’s been happening to them: shouting and laughing and convulsing in their sleep. Dreaming that somebody is out to get them. Drinking gallons of water at a time, as if they’re dying of thirst. Becoming dizzy and passing out in the middle of the day. Waking up in the night to find they’ve torn off all their clothes. Screaming and clutching at their throats, as if someone were strangling them. Lashing out at those around them, and causing others to turn violent, too.
In the midst of the students’ accounts, I ask each of them how long they’d been at the school when these incidents first occurred. One by one, they respond. One month. Two months. A few weeks. Pete and I exchange glances. A pattern like that is hard to ignore.
Now the students have questions of their own. “Why are you here?” they say, their eyes anxious and pleading. Do we have medicine for them? Can we tell them what, exactly, is wrong with them?
Pete pauses for a moment, collecting his thoughts. “This has been happening for many years in Tanzania. Mostly to girls your age,” he says as Rutta translates. “And we think it’s because of nervousness. Anxiety. Stress. You have worries and you have symptoms in your bodies. It’s normal for being away from home for the first time.” This happens all over the world, he tells them—to overworked office workers and nervous mothers and stressed-out cheerleaders. Above all, he says, it’s not dangerous. The tense energy in the room dissipates, understanding and relief passing over the students’ faces.
Yes, maybe the laughter of omuneepo and the laughter of everyday life are inherently different. But it’s also true that these expressions share the same fundamental DNA. They’re both basic, primal signals, designed to alert, to communicate, to connect, and to disseminate. They tap into the core of what we are as social creatures, verbalizing from one person to another what often cannot be said in any other way: either that everything is in good fun or, in the case of hysteria, that something is wrong. And maybe sometimes we’re so busy trying to find reasonable explanations for it all that we miss this underlying message altogether.
No, Pete says to the students, they don’t need medicine to get better. They just need time and support. If they’re feeling anxious or upset or homesick, I add, they should find someone to talk to—a teacher, a friend, anyone at all who’s willing to listen.
Or maybe they just need a good laugh. As we’ve learned from our time here, laughter is a far more powerful social force than most people realize. It can turn strangers into compatriots, crowds into communities, friends into lovers. And most of all, it signals that everything is going to be all right. If these students can joke and laugh with their colleagues, maybe they won’t feel so beleaguered. Maybe they won’t feel so alone.
“It will all be okay,” Pete continues. “There is nothing at all to worry about.”
Or as Rutta would say, “Hakuna matata.”
