CHIMPANZEE SOCIAL BEHAVIOR
Chimpanzees work together in many ways, such as mutual grooming, and exert great energy to maintain their place in their social hierarchy. Chimpanzees have a wide range of facial expressions and even kiss each other. Morality, consciousness and culture, which were all once considered to be uniquely human, have been observed in chimps.
Chimpanzees have a highly fluid social organizations. Sometimes they wander around by themselves. Sometimes they forage in groups with 30 or more chimps. Sometimes they bang on the buttresses of large trees to announce their presence throughout the forest.
Chimpanzees shake hands, back slap, yawn, hug, dance and embrace one another. They also pat each other on the back, hold hands and even kiss each other as a greeting. When old friends haven't seen each other for a long time they run toward each, look each other in the eye, rocking back and forth on their feet while their hair stands on end. Finally, they fling their arms around each other with a welcoming embrace.
Chimps will sometimes sit on logs as if they were chairs. and even keep them as possessions. If another chimp is angry sometimes they will heave the “chair” into the forest. In 1964, Goodall recorded an example of "planning" and "intelligence" when a chimpanzee named Figan "kidnaped" another chimpanzee to get the rest of the group to follow him to another location.
When threatened chimpanzees bare their teeth, hurl sticks and urinate on their attackers. When they are nervous they often reach out and touch one another. Bowing is a chimpanzee gesture of submission. Sympathy towards a friend bloodied in a fight can be expressed with a grooming session. Chimps who are good friends often pass food to each other with their feet and greet each other with soft pants and an extended wrist like a debutante presenting her hand to be kissed.
Figan, a chimpanzee observed by Goodall, cemented his position as dominate male with the help of his brother Faben. When Faben disappeared, Figan had more difficulty fending off challengers but still managed to hold onto power. Japanese chimpanzee researcher Toshida Nishida observed one male chimpanzee that swung the balance of who was the dominate male in the group by allying himself first with an elderly chimpanzee and later with a challenger. "His reward," Nishida said, "was access to estrous females with the interference of his less astute superiors."
The Gombe research team observed similar behavior by a chimp named Goblin that kept changing his alliance with two males—Freud and Frodo—that challenged each other for the position of alpha male. "Goblin sides with whoever looks most powerful," Goodall told National Geographic. "So no matter who wins, he can’t lose. Meanwhile he has access to any female he wants, right in front of everyone. Neither Freud nor Frodo will stop him, or they might lose his support. So smart."
Chimp's Grass Earring — A Sign of Fashion and Culture?
A chimpanzee that wore a grass "earring" proves that animals have culture, fashion and traditions just like humans, according to a scientist's review of decades of research in the field.. The Telegraph reported: “Prof Andrew Whiten, a professor of evolutionary and developmental psychology at the University of St Andrews, said “He explained that animals had a primary form of inheritance from genes but at least some animals — and a wider variety than previously thought — had a "second inheritance system of inheriting by learning from others". [Source: Jessica Carpani The Telegraph., April 2, 2021]
“He suggests that if culture is seen as an array of traditions passed on by learning from others, it is far from unique to humans. In one example of animal culture, chimpanzees studied in a wildlife sanctuary in Zambia were found to develop a cultural tradition of fashionably wearing a grass blade in one ear. One chimp, named Julie, began the trend before others copied, with a majority of the group — eight out of 12 — following suit.
“Discussing Julie, Prof Whiten told The Telegraph: "It's a totally arbitrary behaviour, it doesn't matter whether the chimp does it or not, it’s not of any use. Therefore it does demonstrate something which is shared with our own species, where our culture is so powerful that it becomes almost an end in itself, to be like others to act like others. "That may affect, in the case of humans, how we like to dress, our fashion, how we decorate ourselves, how we do our hair. And here's just a little kind of elementary example showing that even chimpanzees are such cultural beings that they may do that."
Prof Whiten noted that evidence also points to animals continuing to learn culturally right through their lifetime rather than just as juveniles. He added that what was most surprising was "how far the reach of cultures spread across or down the animal kingdom", including a variety of mammals, birds, fish and insects. Even tiny fruit flies showed "mate-choice copying", in which females who see other females preferring certain kinds of males to mate with later show the same preference, a tradition persisting across generations.
“He said: "The all-pervading cultural nature of our species was long thought to define what it is to be human, separating us from the rest of the natural world and the evolutionary processes that shape it. Other species were thought to live by instinct and some ability to learn, but only humans had culture. Over recent decades, a rapidly growing body of research has increasingly revealed a very different picture."
Orangutan Customs and Culture
orangutan Orangutans pass on behavior from one generation to the next. Some of these “customs” are unique to particular groups which some scientist argue is an expression of “culture," which is defined as the ability to invent new behaviors adopted by a group which are then passed down to succeeding generations. It was previously thought that only humans and chimpanzees possessed “culture."
There are a number of examples of orangutans living in one area that possess culture and customs that other groups don't have. One group at Gunung Palung National Park in Borneo, for example, threatens strangers by making kiss-squeaking noise into a handful of leaves. In Sumatra, orangutans use sticks to pry nutritious seeds from prickly, difficult-to-eat Neesia fruits. Others make a raspberry-like noise before turning in for the night, use their fists to amplify sound, employ leaves as gloves when handling spiny fruits, dip leaves in a hole with water and lick the leaves, use leaves as napkins and employ sticks to poke out sections of termite nests.
What is remarkable about the finding compared to other apes is that orangutans are much less social than chimpanzees and humans. Galdikas wrote in Science, “If orangutans have culture, then its tells us that the capacity to develop culture is very ancient...orangutans separated from our ancestors and from the African apes many millions of years ago." The study suggests “they may have had culture before they separated."
Orangutan Dreams, Aggression and Self Awareness
Orangutans and chimpanzees are the only two animals that pass the mark test, a measurement of being self aware. In this test an animal is anaesthetized and marked with an odorless dye above an eyebrow or ear. The animal passes if it touches the mark after being shown a mirror after it wakes up. Apes can recognize themselves in a mirror while monkeys think they are confronted with another monkey.
Apes may dream; they have rapid eye movement. One naturalist described a young orangutan who woke up screaming as if they had just had a nightmare. The orangutan’s turns out had witnessed his mother being shot down from a tree by tribesman and killed, skinned and eaten before his eyes. Orangutans are also quick learners but sometimes at the cost of unanticipated cost. An orangutan couple in Russia followed instructions from a video on good patenting and then became addicted to television and neglected each other.
Bill Brubaker wrote in Smithsonian magazine, Males are frighteningly unpredictable. Galdikas recalls one who picked up her front porch bench and hurled it like a missile. "It's not that they're malicious," Galdikas assures me, gesturing toward the old bench. "It's just that their testosterone surge will explode and they can be very dangerous, inadvertently." She adds, perhaps as a warning that I shouldn't get too chummy with Tom and Kusasi, "if that bench had hit somebody on the head, that person would have been maimed for life." [Source: Bill Brubaker, Smithsonian magazine, December 2010]
When I visited Gunung Leuser National Park in Sumatra my guide told me several stories about aggressive orangutans. The guide said once a large male started chasing him down a trail and rolled itself into a ball and somersaulted down a downhill section of trail to catch up to the guide, who said he was vigorously man-handled by the ape but emerged more or less uninjured.
Chimpanzee and Gorilla Murder
According to some estimates a third of all male chimps are killed in attacks by other chimps. Several cases of chimpanzee homicide have been documented. Chimps are very strong. They can kill with their hands and feet In 1995, Goodall told National Geographic, "When I first started at Gombe, I though the chimps were nicer than we are. But time has revealed that they are not. They can be just as awful."
Goodall said: If a patrol of chimpanzees “meets up with a group from another community, both sides, after exchanging threats, are likely to withdraw discreetly back into home ground. But if a single individual is encountered, or a mother an child, then the patrolling males usually chase and, if they can, attack the stranger. Ten very severe attacks on mothers or old females have been recorded since 1970; twice the infants of the victims were killed; one other infant died from wounds.” Researchers have observed one of group of chimpanzees holding a victim down while others attacked it, even ripping its flesh with their teeth.
Diane Fossey's assistant Peter Veit witnessed an attack by a male gorilla on a diseased female that resulted in death. After she was clearly dead the male repeatedly jumped on her and dragged her body around a trampled down clearing. The incident began when the male and a dominant female in the group began beating their chests near the sickly female, who appeared to have been near death anyway. The male killed her by pounding on her chest until she "let out her only—and also—last vocal sound, a death rattle, as if through stuffed nostrils." The silverback in the group didn't do anything until the female was already dead. The dead female’s 3½ year-old, who watched the entire event, tried to suckle her, also, after she was dead. When Veit left the site and returned 18 hours later he found the murderer still beating his chest by the dead body. Shortly thereafter the entire group wandered off.
Infanticide has been observed among gorillas. Usually it is done by a male to infants fathered by different males to free the nursing females for breeding. The death unusually is quick: a crushing bite to the skull or groin: Fossey said "I now believe infanticide is the means by which a male instinctively seeks to perpetuate his own lineage by killing another male's progeny in order to breed with the victim's mother." Fossey observed the silverback in one group kill an infant in another group that was dissolving so he could claim the mother. Infanticide, Fossey said, accounted for the death of 38 infants over a 13-year period.
Morality and Fairness Among Animals
Melissa Hogenboom wrote for the BBC: “Chimps' social skills are the basis for another behaviour once thought to be uniquely human: morality. Morality can be said to encompass fairness, altruism and empathy. For centuries our moral codes have been crucial to our notion of humanity. We have long believed that our heightened moral reasoning and empathy sets us apart from the beasts.[Source: Melissa Hogenboom, BBC, July 3, 2015 |::|] “We know that children have a strong sense of fairness from an early age. For instance, they will share with friends, even if there is an obvious cost to them. They also seem to be innately altruistic: they will help pick up dropped objects without any prompts from as young as 14 months. But other animals have an innate sense of fairness, too. Capuchin monkeys know what's fair and what's not. |::|
“In 2003 de Waal published research looking into how capuchin monkeys reacted to an unfair payment. After two monkeys had completed the same task, both would happily accept a cucumber as a reward. But when one was randomly given a more delicious grape instead, the other was not happy and began to refuse the cucumber. Chimpanzees behave in a similar way. But what if a chimpanzee controlled the reward instead of a human experimenter? We know that for the most part, they act selfishly when it comes to food. They are known to steal or hide it from rivals.
De Waal’s Capuchin Monkey Fairness Experiment
Capuchin monkey eating a banana
Capuchin monkeys have a strong sense of fairness, even going strike over pay issues. In a famous experiment they refused to do a task and threw down tools their when they saw another monkey get a bigger reward for doing the same task. John Whitfield wrote in Nature: “The experiments show that notions of justice extend beyond humans, says Sarah Brosnan of Emory University in Atlanta, Georgia. This is probably an innate ability that evolved in our primate ancestor, she believes: "You need a sense of fairness to live in large, complex groups." Brosnan and her colleague Frans de Waal taught brown capuchin monkeys (Cebus apella) to swap plastic tokens for food. Normally, monkeys were happy to exchange a token for some cucumber. [Source: John Whitfield, Nature, September 18, 2003 ]
“But the monkeys took offence if they saw a neighbour getting a grape for a token. In about half of such trials, the short-changed capuchin either refused to hand over its token, or rejected the reward. Some threw the token or cucumber clean out of their cage. The animals' umbrage was even greater if another monkey got a grape for nothing. About 80 percent rebelled in some way in this situation. "It's a really neat discovery," says primatologist Charles Janson of the State University of New York at Stony Brook. "The monkey is clearly paying attention to what its neighbour is doing, and realizing that it's getting a better reward."
“But it's not clear how important this ability is in the forests of South America, where the brown capuchin lives, warns Janson. "Capuchin monkeys can learn to do all sorts of things in captivity that they never do in the wild," he says. Capuchins don't hold a grudge, says Brosnan. They worked with her on future trials, and the inequality did not create trouble between animals. "The monkeys were clearly not thrilled, but they weren't visibly anxious," she says.
“Only female monkeys show this pique, the researchers found. Males were much less sensitive to inequality. Their minds may have been on other things, says Janson: "Males care about sex, and females care about food. The males might not consider the food differences worth worrying about." Previous experiments with humans have shown that they become less cooperative if treated unfairly, and punish uncooperative people even if their own reward declines as a result. This is akin to a monkey throwing away the cucumber that it has already worked for. Brosnan is now studying chimps to see if they share this trait with us and capuchins. “
Cooperation and Helpfulness Among Chimps and Animals
Melissa Hogenboom wrote for the BBC: “Chimpanzees also seem to be instinctively helpful. Just like young infants, chimpanzees will help humans reach for out-of-reach objects. A 2013 study found that they also know the value of cooperation. They will share food even if there is nothing obviously in it for them. The study found that they will split a reward equally, just as humans do. In one task chimpanzees shared bananas in the same way that humans share money. They also help each other. Chimpanzees will unlock a door that leads to food for a mate, even if the one doing the unlocking would not get any. In the wild researchers have witnessed chimpanzees helping disabled group members, adopting unrelated orphans and helping friends escape from poachers' snares. [Source: Melissa Hogenboom, BBC, July 3, 2015 |::|]
“This sense of altruism must run deep in the animal kingdom, because rats will also save a friend from being soaked with water, even if it means getting wet themselves. These studies suggest that cooperation is a useful survival trait for many species. If humans, chimps and rats all cooperate, the common ancestor of all three may have done so too. |::|
“"Chimpanzees live in a rich social environment, they depend on each other," says Felix Warneken of Harvard University in the US. "It does not require a big society with social norms to elicit a deep-rooted sense that we care about others." The long-held view that chimps are selfish and mean is no longer acceptable, says de Waal. "People say that morality comes from God, from religion," he says, but we can clearly see the roots of morality in many other species.
Chimpanzees Are Helpful, But Only When Asked
In a paper published in PNAS in February 2012, primatologist Shinya Yamamotoa and colleagues demonstrated that chimpanzees are only helpful to a point: they are usually not very helpful if it means giving up valued things like food, even if they've got more than they need. This true is even between a mother and her infant! Jason G. Goldman wrote in Scientific American: “Why do chimpanzees seem so reluctant to help others? One possible explanation is that they're unable to understand the goals of another individual, resulting in an inability to create any sort of shared intentionality between two individuals. To that end, the researchers write, "many still believe that humans are unique in this respect because we are the only animal species endowed with unique 'theory of mind' abilities enabling us to understand the goals and to share the intentions of others." [Source: Jason G. Goldman, Scientific American, February 13, 2012, Yamamoto S, Humle T, & Tanaka M (2012). “Chimpanzees' flexible targeted helping based on an understanding of conspecifics' goals.” Proceedings of the National Academy of Sciences (PNAS) \~]
“Yamamotoa and the other researchers set up an experiment designed explicitly to address this possibility. The first chimpanzee was given a task to accomplish in order to receive a juice reward. The task required the use of one of two types of tools: a stick or a straw. The stick and the straw, however, as well as five other items were found not in the first chimpanzee's booth, but in the second chimp's booth. There was a small opening between the two booths where the second chimp could pass the necessary tool to the first. By itself, this could test whether or not the second chimp was willing to help the first chimp.\~\
“But to see whether the ability to understand the goal of another individual modulates the potential to help, the researchers created two further conditions: half the time, the barrier separating the two booths was a transparent window, and half the time it was a completely opaque wall. If chimpanzees modulate their responses to a help request based on whether or not they can see the goal of another individual, then they should give the appropriate tool more often when in the transparent window condition. \~\
“During the transparent window condition, the chimpanzees were more likely to offer up the appropriate tool (e.g. a stick during the stick condition, or a straw during the straw condition) than any of the other tools. This result itself shows that the chimpanzees were able to understand which tool their partner would need in order to solve a given task. Importantly, ninety percent of tool offers occurred only after a request was given by the first chimpanzee, suggesting that while chimpanzees may not spontaneously engage in helping behaviors, direct requests are effective in soliciting assistance. \~\
“The results from the opaque window condition might provide some insight into how the chimps determine which tools to provide when asked for help. As in the first condition, chimps were extremely likely to offer a tool after a request was made. In fact, one of the objects (even if not the useful one) was given following a request 98.5 percent percent of the time, on average. While they were more likely to offer one of the two useful tools - the stick or the brush - compared with the other items, the tool that the first chimpanzee needed was not predictive of the tool they were given. In other words, the chimps were not able to infer the precise goals of their partner. They were only able to understand that their partner needed a tool, in a generic sort of way. The one exception to this trend was a chimpanzee named Ayumu, who actually pulled himself up to see through the small window, effectively turning this "cannot see" condition into a "can see" condition. \~\
“The chimps' willingness to help was similar in both conditions. That is, following a request for help, the chimpanzees were equally likely to offer a tool whether or not they could see their partner's situation. While a request might be sufficient to motivate a chimpanzee to help, requests did not provide enough information for the chimps to help effectively. The researchers point out that Ayumu's behavior - selecting the appropriate tool only after looking through the hole in the wall - further reinforces the notion that chimps require visual information in order to help. The researchers conclude, "even without shared intentionality and sophisticated communicative skills, such as language or pointing, chimpanzees can understand others’ goals when situations are visibly obvious and understandable."
“In a sense, though, the findings from this experiment are a bit contradictory: even when they could not visually assess their partner's situation, the chimpanzees were willing to help, and even persisted in offering multiple tools. But when given visual access to their partner's booth, they rarely helped unless directly requested. That is, the ability to infer a partner's goals is not the limiting factor in chimpanzees' altruistic behavior. So...what is?”
Humans More Helpful Than Chimpanzees?
Melissa Hogenboom wrote for the BBC: “Comparative studies between humans and chimps show that while both will cooperate, humans will always help more. Children seem to be innate helpers. They act selflessly before social norms set in. Studies have shown that they will spontaneously open doors for adults and pick up "accidentally" dropped items. They will even stop playing to help. Their sense of fairness begins young. Even if an experiment is unfairly rigged so that one child receives more rewards, they will ensure a reward is fairly split. [Source: Melissa Hogenboom, BBC, July 6, 2015 |::|]
“We know that chimpanzees also work together and share food in apparently unselfish ways. However, Michael Tomasello of the Max Planck institute for Evolutionary Anthropology in Leipzig, Germany, says they will only cooperate if there is something in it for them. "Humans do that too, but in addition they care about what their partner gets. In some experiments we have children as young as 14-18 months who seem to expect their partner to collaborate in certain ways and who share in ways chimps don't." |::|
“Human children are less selective about who they share with. Chimpanzees though, largely only share with close relatives, reciprocating partners or potential mates. Felix Warneken of Harvard University in Cambridge, US, differentiates it like this. Children are "proactive", that is, they help even when presented with only very subtle cues. Chimpanzees though, need more encouragement. They are "reactive": they will hand over objects but only after some nudging. |::|
“Something must have happened in our evolution, Tomasello says, to make humans increasingly reliant on each other. Our brains needed fuel to get bigger and so collaborative hunting may have played a key role in that. Our advanced teamwork may simply reflect our long history of working together to get food.” |::|
Evil and Goodness Among Chimpanzees
chimpanzee teaching tool use in Senegal
Melissa Hogenboom wrote for the BBC: “Of course, with the good comes the bad. It would be misleading to only consider chimpanzees as helpful, moral creatures. Just like us, they have a dark side. There are many instances of fighting, murder and even infanticide. Their society is built upon a complex, hierarchical social world where it is important to keep friends close. That means chimps can get manipulative. [Source: Melissa Hogenboom, BBC, July 3, 2015 |::|]
“ De Waal has called them "Machiavellian", in reference to the deceitful power-grabbing techniques described by historian and philosopher Niccolo Machiavelli. He saw that a dominant male chimpanzee, who had become powerful with the help of friends, became jealous if these allies associated with his rivals. In response, the male would keep them apart. "As soon as his best buddy starts grooming his rival he gets very upset and breaks it up," says de Waal. "That's a 'divide and rule' strategy." |::|
“These insights all suggest that chimpanzees are socially aware and understand each other's behaviour. But how good are they? Humans can recognise the mental states of others, an ability psychologists call "theory of mind". We can figure out what others are thinking and what their intentions are, and infer what another person does or does not know. |::|
“Children learn to do this from a young age, and there is now a lot of evidence that great apes possess many of these mind-reading skills. For example, a subordinate chimpanzee will only pick up a tasty banana if he can do so without being seen by a more dominant chimp. The subordinate knows that the dominant chimp would claim it. |::|
“We are not the only ones who can think about others as individuals with goals Chimps also have some understanding of human minds. They can tell the difference between a person who is unwilling to give them food and a person who is unable to so. |::|
“The latest line of evidence in this field shows that, after food is taken away from them, chimps will steal it back from an opaque box which the experimenter cannot see into. They leave the food in the clear box alone. Clearly, we are not the only ones who can think about others as individuals with goals, intentions and perceptions, says Katja Karg of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, the lead author of the study. |::|
“The next step is to look at whether orang-utans have the same ability, says Karg. We split from them about 14 million years ago, so if they do, it would suggest our mind-reading skills are ancient. Knowing someone else's mental state also requires a conscious awareness of your own. That suggests that chimpanzees also have a degree of conscious awareness. They are not the only ones. So far the ability has been found in many other apes, dolphins, Asian elephants and the European magpie.” |::|
Orangutan make lousy house mates. Galdikas and Brindamour complained that the orangutans that stayed with them ate, drank and ripped open anything the can get their hands on; opened childproof drug containers; and squeezed out all the contents of glue bottles and toothpaste tubes. Not only did the orangutans sleep on their bed they also tore open the mattresses and pillows to get at the edible seeds on the inside. Closing the windows and doors wasn't enough to keep them out. The orange apes simply tore down the walls and knocked holes in the roof to get in.
The problems didn't stop there. They ate candles, drank shampoo and sucked on batteries like lifesavers. Usually not satisfied with drinking milk they also like to gargle with it and spit it out all over each other. One had a fancy for flashlight bulbs and another like to suck all the ink out of fountain pens.
Orangutans also like to play with dogs, cats and small children. They enjoy kissing and scratching their playmates but what seems to give the orangutans the greatest pleasure is placing their friends on their head. In zoos, stressed out orangutans respond well to aroma therapy and are particularly relaxed by rose oil.
Orangutans have been killed for raiding crops. Other have their fingers chopped for stealing eggs. Humans who have been attacked or injured by orangutans usually provoked the animals in some way.
Karta came within a few yards (meters) of visitors, who were the first to notice the animal's escape bid. Whitehead said the animal was not aggressive, but the zoo was cleared as a precaution, and veterinarians stood by with tranquilliser guns in case of trouble. Officials at the zoo in the southern city of Adelaide would conduct a "thorough review" of the escape bid and it was likely some vegetation that could be used in a future try for freedom would be removed from Karta's enclosure.
Orangutans Troublemakers
illustration from 1900
Apes Have Ability to Work Out What Other Are Thinking
In a study published in 2016, great apes showed that have key abilities to see the world from point of view of others and discern what others are thinking — traits that once was considered uniquely human. Seth Borenstein. Of Associated Press wrote: “An international study found that chimpanzees, bonobos and orangutans seem to have this ability, even when they know that point of view is dead wrong. It’s called theory of mind, or the ability to know that others have different beliefs and perspectives. [Source: Seth Borenstein. Associated Press, October 7, 2016 /*]
“Researchers in the Japan, the United States, Germany and the United Kingdom put a specific part of theory of mind to the test — understanding that someone else may have false beliefs — and the apes passed, according to a study in Science. While apes had shown other aspects of understanding others’ perspectives, previous studies had not shown them to grasp the complex concept of understanding others’ false beliefs, said study authors Christopher Krupenye and Fumihiro Kano. It’s a concept humans develop around age 4 or 5. /*\
“Researchers tracked the eye movements of the apes as they watched 40-second movies that showed someone in a King Kong costume trying to fool a man. The man watches King Kong either hide a rock in a box or — in a different version of the experiment — hide himself in a hay bale. Then, after the man leaves, King Kong moves the rock or moves out of the bale. So at this point, the man doesn’t know the rock or King Kong has moved — but the ape watching the movie does. When the man returns, the ape looks at where the man last saw the rock or King Kong, showing that it can anticipate the man’s false belief that the rock or King Kong remains in the same place. /*\
“That shows that the ape is getting the concept of others’ false beliefs, and this is a “critical” aspect of cognition, said Kano, a comparative psychologist at the University of Kyoto. Apes have some understanding of others’ actions and can predict others’ actions even when those individual are acting on misinformation,” said Krupenye, who conducted psychological research at Duke University and is now at the Max Planck Institute in Germany. “This kind of skill is central to a lot of sophisticated human behavior that we use in cooperative context and culture and communications.” But this may not be a full understanding of others’ false beliefs, Kano cautioned. /*\
“Yale cognitive science professor Laurie Santos called the test results “really remarkable” and “very surprising” because tests in the past have not found primates understanding someone else’s false beliefs. But Santos said she’s reserving judgment because the study’s sample size is small — 29 apes — and there is no good explanation why the apes pass this test and failed other, similar ones. Joel Fagot and Raphaelle Malassis at Aix-Marseille University said in an email that it was “a very exciting study on an important question, but this study is probably not THE definitive demonstration of false belief in apes.”“ /*\
Chimps and Orangutans Experience Midlife Crises?
A study published in 2012 in the journal Proceedings of the National Academy of Sciences suggests the captive apes experience a kind of “mid-life crisis” and their well-being declines in middle age but picks up as they approach old age Ian Sample wrote in The Guardian: “An international team of scientists claims to have found evidence for a slump in wellbeing among middle-aged chimpanzees and orangutans. The lull in happiness in the middle years, they say, is the great ape equivalent of the midlife crisis. The study has raised eyebrows among some scientists, but according to the authors, the findings suggest that the midlife crisis may have its roots in the biology humans share with our closest evolutionary cousins. "There's a common understanding that there's a dip in wellbeing in middle age, and that's been found in many datasets across human cultures," Alex Weiss, a psychologist at Edinburgh University, told the Guardian. "We took a step back and asked whether it's possible that instead of the midlife crisis being human-specific, and driven only by social factors, it reflects some evolved tendency for middle-aged individuals to have lower wellbeing." [Source: Ian Sample, The Guardian, November 19, 2012]
“The team from the US, Japan, Germany and the UK asked zookeepers, carers and others who worked with male and female apes of various ages to complete questionnaires on the animals. The forms included questions about each ape's mood, the enjoyment they gained from socialising, and their success at achieving certain goals. The final question asked how carers would feel about being the ape for a week. They scored their answers from one to seven. |=| “More than 500 apes were included in the study in three separate groups. The first two groups were chimpanzees, with the third made up of orangutans from Sumatra or Borneo. The animals came from zoos, sanctuaries and research centres in the US, Australia, Japan, Canada and Singapore. |=|
“When the researchers analysed the questionnaires, they found that wellbeing in the apes fell in middle age and climbed again as the animals moved into old age. In captivity, great apes often live to 50 or more. The nadir in the animals' wellbeing occurred, on average, at 28.3 and 27.2 years old for the chimpanzees, and 35.4 years old for the orangutans. |=| "In all three groups we find evidence that wellbeing is lowest in chimpanzees and orangutans at an age that roughly corresponds to midlife in humans," Weiss said. "On average, wellbeing scores are lowest when animals are around 30 years old." |=|
“The team explains that the temporary fall in ape wellbeing may result from more depressed apes dying younger, or through age-related changes in the brain that are mirrored in humans. Weiss conceded that, unlike men, great apes are not known to pursue radical and often disastrous lifestyle changes in middle age. |=|
“Robin Dunbar, professor of evolutionary psychology at Oxford University, was dubious about the findings. "What can produce a sense of wellbeing or contentedness that varies across the lifespan like this? It's hard to see anything in an ape's life that would have that sort of pattern, that they would cogitate about. They're not particularly good at seeing far ahead into the future, that's one of the big differences between them and us." Alexandra Freund, professor of psychology at the University of Zurich, was also sceptical. She said the concept of a midlife crisis was shaky even in humans. "In my reading of the literature, there is no evidence for the midlife crisis. If there's any indication of decline in emotional or subjective wellbeing it is very small and in many studies, it's not there at all." |=|
“But Weiss believes the findings could point to a deeper understanding of the emotional crisis some men may experience. "If we want to find the answer as to what's going on with the midlife crisis, we should look at what is similar in middle-aged humans, chimps and orangutans," he said.” |=|
Image Sources: Wikimedia Commons
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Last updated April 2024