Why Do We Laugh?
Laughter can be so healing, it seems; “Laughter is the best medicine,” the saying goes. But, is that really true? Does humor serve some adaptive purpose? And if it’s good for us, why do we find some things funny while others leave us flat?
For answers, look no further than the new book, Ha!: The Science of When We Laugh and Why, by cognitive neuroscientist Scott Weems.
Weems explains what humor is, how things become funny, and why evolution gave us laughter. According to Weems, laughter and humor help us process conflict in our environment through the dopamine that is released in our brains when we find something funny. Dopamine relieves tension—which I discovered with my son —but it’s also implicated in motivation, memory, and attention, affecting processes as varied as learning and pain management. It may seem impossible to study humor; but scientists have found ways, mostly through large surveys and fMRI research.
“What elicits laughter isn’t the content of the joke but the way our brain works through the conflict the joke elicits,” writes Weems.
Take for example an old Groucho Marx joke: “One morning I shot an elephant in my pajamas. How he got in my pajamas, I don’t know.” Our brains will read the first sentence and be taken down a path imagining Grouch Marx on a safari in his pajamas, before we get the new image of the elephant actually inside his pajamas. That process of moving from one possible solution to the next involves a part of the brain called the anterior cingulate, or AC, which becomes more active when there are conflicting interpretations in the brain. The AC helps to quiet down the “louder” parts of the brain (associated with the expected response) to allow other quieter answers to emerge, and it’s particularly active during jokes. It helps us to figure out the novel solution, which, when resolved, gets incorporated into the brain and gives us that spike of dopamine.
This is why we feel so good when we get a joke, and why jokes are not funny the second time around.
Humor is an important part of our evolution, claims Weems—and other animals, such as rats, have been shown to have a sense of humor, too. If one tickles a rat by scratching its belly, it emits high-pitched laughter (normally outside of the human hearing range).
Experiments on humans have found that laughter can increase blood flow and strengthen the heart, much like aerobic exercise does. Laughter also helps decrease one’s threshold for pain, although not all humor is the same in this respect. According to Weems, positive humor—humor that looks for the bright side of troubling situations—is beneficial to our health, while darker, sardonic humor is not.
Importantly, humor is also great for our social relationships. People list having a sense of humor as one of the most important traits in a mate. In classrooms, a humorous teacher makes learning more enjoyable and increases a student’s motivation to learn.
In one study at San Diego State University, students enrolled in an Introductory Psychology course were taught using three kinds of lectures: one that incorporated course content-related humor; one that included humor, but not related to the course material; and one that used no humor at all. When researchers tested student’s retention of knowledge six weeks later, they found that those who attended lectures with course-related humor scored significantly higher than the other students.
Because humor is so good for us, and because it can be contagious, Weems suggests incorporating it more in our lives. He suggests going so far as to laugh the next time you hear a joke, even if it’s not particularly funny.
Laughter for Social Bonding
One morning 10 years ago, psychologist Jaak Panksepp walked into his lab and made an unusual proposition to a research assistant: “Come tickle some rats with me!” Panksepp wasn’t just trying to entertain himself, or his lab rats. He was trying to solve one of the great questions of human evolution: Why do we laugh? “Laughter is one of those human mysteries about which we know essentially nothing,” Panksepp cheerfully admits. To solve this mystery, scientists have probed the brain circuits involved in human laughter, but this research has faced a number of limitations. For one, though researchers have used sophisticated equipment to observe people’s brain activity while they read cartoons or jokes, this equipment is quite sensitive to movement—a major drawback when you’re trying to induce a hearty belly laugh.
So researchers have turned instead to some of our furry cousins in order to learn more about laughter. Over the past few years, several different labs have begun to uncover different forms of laughter in species ranging from chimpanzees and bonobos to dogs and even rats. In addition to helping identify the biological machinery involved in laughter, these animal studies have also shed light on laughter’s evolutionary significance. Laughter, this research suggests, isn’t merely a way to signal joy. It may also be a vital, age-old tool used to promote social bonding and to help individuals improve their standing within a group.
Laughter does sound different across species, of course. Chimpanzee laughter sounds more like rhythmic panting, and rat laughter is so high-pitched as to be undetectable without specialized equipment. And, as we all know, it even varies among individuals within a species (think Janis on Friends). However, the basic vocal pattern to laughter is remarkably familiar across the animal kingdom, and it is often expressed in similar social situations. Indeed, our tendency to laugh appears to be hardwired. Human babies, even those born both deaf and blind, will smile, gurgle, and laugh by the age of four months.
It is precisely this more childlike, instinctive form of laughter that scientists believe they have uncovered in rats. Panksepp, the Baily Endowed Chair of Animal Well-Being Science at Washington State University, has found that rats emit their high-pitched chirps when tickled, especially in areas, such as the nape of the neck, that are targeted by fellow rats during playful bouts. They make the same sounds when playing or anticipating playtime with one another, as well as when anticipating a reward. Other research has found that this chirping is common when rats enter new environments or encounter new animals; Panksepp likens this to nervous laughter in humans.
As rats age, their chirping generally becomes less frequent. A similar phenomenon seems to occur in humans: Research done by William Fry, a professor emeritus at Stanford University School of Medicine, has found that kindergarteners laugh 300 times a day, whereas adults laugh just 17 times. However, rats who were tickled often when young usually retain their tendency to chirp later in life. Studies with rats have also suggested several reasons why laughter may be innate to so many different animal species. Panksepp and others have noticed that chirping occurs when rats are sizing each other up in the moments before a potential fight, which may mean that laughter can help diffuse situations that might otherwise escalate into physical conflict.
Similar behavior has been documented among chimpanzees. A few years ago, Takahisa Matsusaka, then a graduate student at Kyoto University in Japan, observed that when young chimps were tickled or chased, they made vocal sounds that sounded like laughs, which he called “play-panting.” Matsusaka suggests that play-panting signals to their partners that they want to keep playing, especially during interactions that contain mock-aggressive acts.
A recent paper in the journal Behavioral Brain Research builds upon this observation. The authors of this paper suggest that when primates like chimps engage in “fragile interactions”—such as fake fights that border on actual violence—laughter may serve as a strategy to keep it light. In an interview, Martin Meyer, a researcher at the University of Zurich who was the lead author of the paper, says he believes primates use laugh-like vocalizations primarily when they’re in a subordinate position, trying to appease a potential assailant.
In light of these findings, it’s not hard to understand how, in any highly social species, natural selection might favor those who laugh. Laughter may help some animals avert an attack, and according to Panksepp, animals may be attracted to others who laugh, seeing their laughter as a sign that they have a positive temperament and can get along well with others—and some of those positive interactions could lead to reproduction.
“Laughter indicates emotional health, just as a peacock’s tail indicates physical health,” he says.
Indeed, just as humans like to spend time with their funny friends, Panksepp has found that rats gravitate towards those who “chirp” the most.
Though animals can illuminate our own human tendency to laugh, no study of rats will ever explain why we chuckle at The Daily Show, and researchers are under no illusion that animal laughter is identical to our own. As Panksepp points out, rat arms and human arms have all the same joints, and one can be a good model for the other, but they’re not interchangeable. Still, research so far has yielded insights that may help us better understand both why we laugh and why we sometimes don’t, such as during bouts of depression or anxiety. In the meantime, Panksepp and his colleagues are busy tickling away.
Originally from Greater Good
