Study: Chimps Calm Each Other With Hugs, Kisses

-1.jpgJune 16, 2008, – For most folks, a nice hug and some sympathy can help a bit after we get pushed around. Turns out, chimpanzees use hugs and kisses the same way. And it works. Researchers studying people’s closest genetic relatives found that stress was reduced in chimps that were victims of aggression if a third chimp stepped in to offer consolation.

“Consolation usually took the form of a kiss or embrace,” said Dr. Orlaith N. Fraser of the Research Center in Evolutionary Anthropology and Paleoecology at Liverpool John Moores University in England.

“This is particularly interesting,” she said, because this behavior is rarely seen other than after a conflict.

“If a kiss was used, the consoler would press his or her open mouth against the recipient’s body, usually on the top of the head or their back. An embrace consisted of the consoler wrapping one or both arms around the recipient.”

The result was a reduction of stress behavior such as scratching or self-grooming by the victim of aggression, Fraser and colleagues report in Tuesday’s edition of Proceedings of the National Academy of Sciences.

Dr. Frans de Waal of the Yerkes Primate Center at Emory University in Atlanta said the study is important because it shows the relationship between consolation and stress reduction. Previous researchers have claimed that consolation had no effect on stress, said de Waal, who was not part of Fraser’s research team.

“This study removes doubt that consolation really does what the term suggests: provide relief to distressed parties after conflict. The evidence is compelling and makes it likely that consolation behavior is an expression of empathy,” de Waal said.

De Waal suggested that this evidence of empathy in apes is “perhaps equivalent to what in human children is called ‘sympathetic concern.'”

That behavior in children includes touching and hugging of distressed family members and “is in fact identical to that of apes, and so the comparison is not far-fetched,” he said.

While chimps show this empathy, monkeys do not, he added.

There is also suggestive evidence of such behavior in large-brained birds and dogs, said Fraser, but it has not yet been shown that it reduces stress levels in those animals.

Previous research on conflict among chimps concentrated on cases where there is reconciliation between victim and aggressor, with little attention to intervention by a third party.

Fraser and colleagues studied a group of chimps at the Chester Zoo in England from January 2005 to September 2006, recording instances of aggression such as a bite, hit, rush, trample, chase or threat.

The results show that “chimpanzees calm distressed recipients of aggression by consoling them with a friendly gesture,” Fraser said.

Consolation was most likely to occur between chimpanzees who already had valuable relationships, she added.

The research was supported by the Leakey Trust.

IN THE SHADOW OF MAN by Jane van Lawick-Goodall. 297 pages. Houghton Mifflin. “I saw a black shape hunched up on the ground. I hunched down myself . . . in the thick undergrowth. Then I heard a soft hoo to my right. I looked up and saw a large male directly overhead. All at once he uttered a long drawn-out wraaaai . . . one of the most savage sounds of the African forest … I forced myself to appear uninterested and busy, eating some roots from the ground. The end of the branch above me hit my head. With a stamping and slapping of the ground a black shape charged through the undergrowth … I expected to be torn to pieces. I do not know how long I crouched there before I realized that everything was still and silent again, save for the drip-drip of the raindrops.”

With this scene of primeval terror, a young Englishwoman named Jane Goodall began an intimacy with the chimpanzees in the rain forests of Tanzania that has lasted a decade and produced one of natural history’s most impressive field studies. In this book she has greatly expanded the preliminary report on her experiences, My Friends: The Wild Chimpanzees (1967); the photographs speak a volume in themselves. In the Shadow of Man should become an instant animal classic.

Scary Scrapes. Jane was 26 and a scientific nonentity when she began her work. Born in London in modest circumstances, she worked as a secretary when she arrived in Nairobi. Struck by her feeling for animals, Africa’s world renowned paleontologist, Dr. L.S.B. Leakey, wangled a grant and packed the young lady off to chase chimps. At first she could not get within 500 yards of her subjects. Real discoveries started, however, when a bold chimp she called David Graybeard strolled into her camp one day and began chewing on a palm nut. Lured by bananas, his friends followed. Jane in turn followed the band on its jungle journeys—sometimes, despite scary scrapes with leopards, she even stayed with them all night—and gathered impressive evidence that the chimpanzee has a far more complex life-style than anybody had supposed.

Like men, she quickly discovered, chimpanzees are technological animals. They chew leaves to make sponges, which they use to sop water out of hollow branches. They also strip grass stems to make long probes, which they use to fish tasty termites out of their mounds. Jane also found out that chimps, long considered vegetarians, also eat meat. Like primitive humans, they form hunting parties and carry out fairly intricate plans to capture young bush pigs, monkeys, baboons—and even, she reports, human babies.

Prodigies of imagination. Compared with the behavior of any species except man, the chimp’s social life is richly sophisticated. They have a wide range of intelligible expressions: fear, rage, hunger, shock, confusion, boredom, irritation, amusement, worry, pleading, mischief, tenderness, embarrassment—even a look of comic alarm that reminded Jane of refined English girls watching horror movies. The chimps also smile, hold hands, dance when it rains, play simple games and stage hugging-and-backslapping orgies when they discover a new fruit tree.

Status is important to both sexes, but among the males it seems to matter as much as food, perhaps more than sex. The struggle to achieve it calls forth prodigies of creative imagination. Mike, a low-ranking male of unremarkable physique, seized supreme power in his group by a stroke of genius. He grabbed a couple of empty kerosene cans from the author’s camp and then charged at the other males, bellowing ferociously and banging the cans together as he came. Appalled by the din, his rivals fled. Swaggering absurdly, Mike challenged Goliath, the dominant male, and in a drama of display and roaring counter-display he broke the older male’s nerve. After that, whenever the two met, they rushed up to each other like a couple of rival jocks and worked off their anxiety by hugging, slapping, grooming—and kissing each other on the neck. “Never, however,” the author reassures us, “have we seen anything that could be regarded as homosexuality in chimpanzees.”

On the whole, in fact, sex was the least serious problem in a chimpanzee’s relations. Total promiscuity was the rule, but now and then a male developed a platonic passion for a special female and followed her everywhere, whether or not she was in heat. Sometimes his feeling was returned, and in that case something like a chimpanzee marriage was made. At times sexual fidelity was a part of the contract. At the other extreme, one of the dominant males would sometimes try to assemble a harem. At the first opportunity, the females usually flew the coop.

A Model Mother. Most females were more interested in children than they were in males. Jane found that chimp mothers who made their babies get out on their own at an early age wound up with clinging, frightened children. Steady, loving and even indulgent mothers, in contrast, generally had happy, independent offspring. Flo, a perfectly hideous old chimp who for reasons beyond human imagination made all the males go ape at mating season, was a model mother when the study began. She played with her babies continually, picked them up at the first whimper, followed every slap with a squeeze and cleverly distracted her child when she saw misbehavior in the making; but as she grew older she became grandmotherly and spoiled one little chimp rotten. As he approached maturity, he was still a screaming ninny.

Unlike Sunday Darwins like Robert Ardrey (African Genesis), Jane van Lawick-Goodall does not press the homo-simian parallels or insist that psycho-cosmic mysteries can be solved by watching a bunch of monkeys in a tree. Yet the parallels are strong, and so is the reader’s temptation to see in the chimpanzee a hairy mirror of mankind. A woman as well as a scientist, Jane loves her subjects and makes the reader love them too—not as clever pets but as serious and struggling individuals. All the more painful, then, to be told that throughout Africa chimpanzees are being shot for the pot by natives and pursued by professional hunters who knock off the mothers and ship the babies to zoos and laboratories. To one who has read this book, the fact that people kill chimpanzees seems only slightly less sickening than the fact that people kill people

Although bonobos have been called pygmy chimpanzees, their behavior is very different from chimps. They are more peaceful and are led by the females, instead of males. Bonobos really like, uh, making love for the sake of making love. That’s really unique in the animal kingdom. They also use this peaceful activity for conflict resolution. They’ve even been called the hippies of the rain forest (Make Love, Not War!).

The last of the great apes to be discovered, the bonobo shares more of our DNA than any other animal on earth. (Some scientists argue that the chimpanzee is just as closely related since the two are so similar.) Sadly, the bonobo has been considered endangered by the IUCN Red List of Threatened Species since 1996.

We don’t really know how many bonobos exist today. They are scattered around in one of the largest rain forests in the world: the Congo basin. Estimates range from 5,000 to 50,000 with bonobos existing only in pockets of their original range. Surveys have shown that their numbers are declining. Learn more about the animals of the Congo basin at this World Wildlife Federation page.

Hunting is a major threat to bonobos. It’s difficult to imagine these creatures being smoked and sold in bushmeat markets, but that is happening very often. Habitat destruction is another big concern for the bonobo. Increasing human population and political instability of the Congo also make the future survival of the bonobo uncertain.

The Bonobo Conservation Initiative (BCI) is the only international organization dedicating itself solely to helping the bonobo. Among many other projects, BCI rescues bonobo orphans who’ve lost their moms to hunting. One of their major projects is the Bonobo Peace Forest, a place of conservation and research. You can read about all of BCI’s many projects here.

Help the bonobo.

While bonobos live only in the rain forest of the Congo (the second-largest in the world), anything that you do to help protect any rain forest helps endangered wildlife.

Several studies shed light on where aggression comes from and how it can be controlled
By Kristin Leutwyler

KISS AND MAKE UP: A female chimpanzee (right) kisses a dominant male with whom she has fought. After aggressive conflicts, monkeys usually make dramatic gestures of reconciliation that include hugging and kissing.

Science may never be able to explain in full such violent acts as the shooting at Columbine High School, which claimed 15 lives 15 months ago. But various studies¿some probing the evolutionary origins of aggression, and others, our conscious ability to control it¿are changing the ways in which researchers regard violence. Two papers review several recent lines of thought in the July 28 issue of Science.

One intriguing perceptual shift is coming from those who regularly observe our closest kin, the chimpanzees, and other monkeys. Indeed, primatologists are now suggesting that aggressive behavior be viewed as a normal means for competing and negotiating within groups, and not as a fundamentally antisocial instinct. This shift, they say, could lead to a better understanding of how aggression ends and can be kept under control among humans.

Although it is hard to look at violence as anything but an attempt to destroy community, Frans de Waal, the C. H. Candler Professor of Primate Behavior at Emory University, makes a compelling argument for seeing it as an integral part of any social network. Were aggressions truly antisocial acts, he points out, there would be no way to explain the fact that the overwhelming majority of attacks involve people who know one another well. And it wouldn’t explain the ways in which colonies of monkeys pick fights or make peace.

Primatologists first began to study aggression as a social phenomenon during the 1970s, when a curious incident was recorded at the Arnhem Zoo after a dominant male chimp attacked a female. The rest of the colony came to her aide, and then screamed and chased one another for a while. After a tense period of silence, the entire group began hooting, and during this chorus, two chimps embraced each other and kissed. When researchers reexamined the event, they realized that the two who had kissed were the very same two that had been fighting. Soon they found that most monkeys and apes make dramatic gestures of reconciliation after conflicts.

Additional research since then has shown that monkeys are actually more likely to seek contact with former opponents than with others, which indicates that they do not start a fight to alienate themselves from another individual but rather to renegotiate the terms of an ongoing relationship. And peacemaking, an important part of this negotiation, appears to be in part a learned skill. Of interest, de Waal notes, one of the best predictors of whether schoolchildren make peace is the level of positive contact they have had before a conflict erupts.

Accepting the idea that a cycle of violence and reconciliation provides a natural way of redefining the terms of relationships does not mean, of course, that it is the only way. And there can be no denying the fact that individuals have different thresholds for acting out. In an accompanying review to de Waal’s essay, Richard Davidson, Katherine Putnam and Christine Larson of the University of Wisconsin put forth the theory that a diminished ability to regulate negative emotions¿including fear, anger, distress and agitation¿can heavily predispose people to impulsive bursts of aggression.

FAMILY COURT: Rhesus monkeys frequently fight with relatives but maintain close bonds through reconciliations. Shown are two adult sisters, sitting to either side of their mother, making peace after having bitten each other.

The neural circuitry involved in quelling negative emotions appears to involve an inhibitory connection from part of the prefrontal cortex to the amygdala, and Davidson and his colleagues cite several lines of evidence as support. In rodents, for example, lesions to the prefrontal cortex render the animals much slower at eliminating aversive responses. Similar lesions in humans produce syndromes marked by impulsivity and aggression. And positron emission tomography (PET) scan studies have shown that murderers tend to have decreased glucose metabolism in the prefrontal cortex, as well as increased activity in parts of the amygdala.

Among 43 normal subjects, the authors tested individual variations in the circuit by first arousing negative emotion and then giving instructions to enhance, maintain or suppress that emotion (for details on the experiment, see sidebar.) They then measured the subjects’ tendencies to startle¿a reaction produced by the amygdala in response to negative emotion. As it turned out, subjects asked to suppress the negative emotion showed much lower “startle magnitudes” than those asked to maintain or enhance their feelings, meaning these people had successfully activated the circuit.

What’s more, the neuroscientists found in subsequent work that among people asked to suppress negative emotions during the experiment, those who were best able to dampen their startle response also showed greater electrical activity in the prefrontal scalp regions, suggesting that the prefrontal cortex was very likely playing its inhibitory part. And given how well the level of prefrontal activation predicted an individual’s ability to control negative emotion, it is conceivable that such testing might provide a way to screen for people at high risk for aggressive behavior.

The good news is that if such people can be identified, it might be possible to provide therapy. Davidson and his colleagues note that both genes and environment contribute to the development of this circuit regulating emotional control, and so interventions involving medication and psychosocial training could improve its functioning. Such treatment could not eliminate aggressive impulses, but it might insure that people at risk for becoming violent could better regulate those urges. And nurturing control and peacemaking skills may not rid society of violence, but it would be a valuable start.

Every Once In a While, We Need to be Stupid