by According to a new study, great apes have a penchant for joking and humor – a finding that sheds new light on the origins of human humor.
All species of great apes tease, tweak and sometimes torment their peers and older relatives – then stand back and watch the results, according to findings published Tuesday in Royal Society B.
The paper suggests that humor is a widely shared trait of the insect gene tree, pushing back the origin of the “fun instinct” in humans to at least 13 million years ago, when the great species of geese began to splitting.
It also sheds light on an exciting new line of inquiry that has emerged in the 21st century: the idea that play and non-immediately practical behaviors may play a larger role in animal life than was generally thought in the 20th century.
“We hope to entertain the possibility that animal minds are not always serious – not always about the next action needed to survive,” said co-author Erica Cartmill of the University of California, Los Angeles (UCLA).
“It’s a serious study of a non-serious topic,” she said.
In the footage collected by the researchers, members of the four groups of great apes — gorillas, chimpanzees, bonobos and orangutans — display the necessary, provocative and playful behaviors familiar to anyone who has spent time around young children.
The behavior, somewhere between play and attack, followed a consistent trajectory. When an apa was sitting around and relaxed, one monkey – generally though not always a youth – would be in size up a target, generally an adult.
Then, the teaser would deliberately provoke the target, usually by hitting, hitting, pulling or jumping on top of them – then stand back and wait for a reaction.
This stage at the end – which the lead scientists call “looking at a response” – was “extremely interesting,” said lead author Isabelle Laumer, a primatologist at the Max Planck Institute.
“They look toward the target, probably because they want to see their reaction,” Laumer said. If they didn’t get a reaction, the teaser would usually try again – but now at a higher intensity.
A few other patterns stood out. First of all, adults and youths teased each other in different ways: A youth might hit an adult, and an adult would only tease or tickle a youth.
And while young primates’ closest companions are often their mothers, moms were generally not the targets of teasing—though older siblings were disproportionately.
Adults usually greeted this teasing with half-hearted rebukes or retreats – pushing the teaser away, getting up and moving somewhere else – although in about a third of the cases they responded with displeasure or amusement.
And while teasing patterns were very consistent across the different species of great apes, among orangutans – a species known for their flowing orange hair – hair pulling was far more common as a means of attention. to find than was among their short-haired. cousins like chimpanzees and bonobos.
These findings—like much from the emerging research on animal cognition and sociality—are beyond the obvious and revealing.
On the one hand, the results represent scientific support for something that anyone who has visited a primate enclosure at a zoo has had a good chance of seeing.
In her previous work with great apes, Laumer said, “I’ve seen in the zoo — they sneak and drag on [each other’s] hair from behind.”
This type of behavior is well illustrated in the scientific literature, noted by luminaries such as Jane Goodall or Frans de Waal.
“Juveniles in the Arnhem Zoo chimpanzee colony often interfere with the adult members of the group,” primatologist Otto MJ Adang wrote in a classic 1986 paper.
Again and again, Adang wrote, younger chimpanzees would act like adults and “throw sticks and sand at them, hit them from behind, etc., and they would immediately shoot. This happens without apparent provocation and despite the possibility of punishment.”
For years, however, scientists tended to categorize this behavior as low-level overt aggression — described by words such as “cruel,” “pain” or ” harassment” — or as play.
In Adang’s studies, for example, he specifically rules out such provocations as “stimulation” if they are accompanied by a characteristic primate expression called “play face.”
And one 2017 paper refers to a similar cluster of behaviors among bonobos as “harassment of adults by immatures.”
But this does not miss the way that teasing, mocking and clowning are somewhere between the two categories, UCLA’s Cartmill said.
“There’s a kind of teasing in the middle,” she said. “It has some aggressive qualities – you’re doing it to provoke a reaction – but within an intimate relationship that’s fun.”
One key aspect of these interactions, she noted, is that “they happen when animals are in a relaxed state — sitting around like two kids in the back of a car seat on a road trip, snuggling up to each other. Or offering something and pulling it back, or leaning really close to put my face to yours – ah, now you’re angry.”
These behaviors can be fun, she said – but they are also something different from play. “The unscientific term is: They are their own market.”
Cartmill conceded that this comparison of human babies in backpacks to squishy troops of chimpanzees might sound a lot like the old bogeyman of animal behavioral science: anthropomorphism, or the idea (ubiquitous in, say, children’s cartoons) that similar animal behaviors. human heads.
“The Apes aren’t telling sophisticated jokes,” she said – noting that even the simplest and most engaging “dad joke” is often presented at a level of complexity that requires not just the ability to speak but a deep fluency in culture.
To launch an annual lecture on this point, Cartmill shows undergraduates a list of “horrible eye stories,” such as a cartoon showing a pickle in a top hat and a cane with the caption “I’m kind of a big dill.”
“To get that joke — and even understand why it’s a terrible joke — no other species can,” she said.
But in a discipline where animals are often seen as complex machines unconsciously running on program-like stimulus and response inputs, she said, clear comparisons between humans and animals can offer a “reality check” to help scientists ask better questions. .
And many of the comparisons are tantalizing. Laumer, the Max Planck primatologist, cited a 2021 study by the paper’s UCLA co-author Sasha Winkler, which found a strong overlap between human laughter and “play voices” in primates.
(That study suggested that the “ha ha” characteristic of human laughter “evolved from an auditory cue of labored breathing during play.”)
Other studies have shown that one of the cornerstones of the idea that humor is unique to humans — that we need at least enough language to understand why that pickle is a big dill — is not true.
Human infants as young as eight months, for example, are already beginning to play with the expectations of others, as found in a 2015 paper on the subject. “Before they talk or walk or crawl, babies make jokes,” write scientists Vasudevi Reddy and Gina Mireault.
“Even in the first year of life, infants create and maintain novel humorous initiatives,” they found, including “actively seeking opportunities to elicit laughter from others by playing the ‘clown’ and to playfully provoke others by teasing them.”
Like the ones practiced by young adults, these jokes for toddlers are not particularly complicated: They may involve broad comic gestures, for example, throwing a shoe on one’s head, or offering a toy to a parent and withdraw it.
This kind of playful early teasing — which Tuesday’s study suggests is common among the great apes — could be the building blocks of what our species eventually presents as, say, political cartoons and humor. stand, said Cartmill.
But for young adults and young people alike, she said, it can also teach valuable lessons about social norms and the characteristics of individual relationships—how much you can push your sibling before he goes crazy. legitimately – as well as reaffirming and strengthening it. relationships. (As Laumer said, quoting a German proverb, “Those who love each other, win each other.”)
One central feature of humor, after all, is that it is social: both young apes and human children seem to draw their understanding of what is funny – and what is scary or frightening – from how adults and adolescents respond more senior
For young children, Mireault and Reddy write, “Other people’s emotional reactions—their laughter, amusement, anger, surprise, annoyance, and fear—are central to their humor, which ‘open the doors’ of humor.”
This social context now represents the source of some of the most unanswered questions about the building blocks of humor in animals. Because the scientists looked at small groups of captive monkeys, they were unable to investigate how humor functions in larger or more complex social groups.
For example, is teasing more common in front of other people than when both parties are alone – and does it matter if the other parties are socially popular? And how do these behaviors change in chimpanzees in the wild?
“I’m not saying that apes have jokes,” Cartmill said, “but they may have teasing cultures that vary from group to group.”
In order to see these differences – or notice them in species more distant from us than the apes – it will be necessary to move past the old assumptions about what animals are capable of doing, she argued.
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