Why bullying is such a successful evolutionary strategy

August 29, 2016 | Author: Mike Dreiblatt | Views: 555 | Comments: 0

By Melissa Hogenboom

Frodo ruled with an iron fist. He incited fear among his fellow group members.

His "demonic streak", as it was later called, started early. From three years old he was throwing rocks at those around him.

Frodo, a large-bodied chimpanzee with a recognisable grey streak, would later become the alpha male of his group in Tanzania's Gombe Stream National Park. The primatologist Jane Goodall called him a "real bully". She had even predicted his rise back in 1979, writing: "In about twenty years one of these two brothers probably will become the alpha."

All the other chimps feared Frodo, which helped his rise to the top. He even pushed himself on his own mother, and fathered a sickly infant with her, who would not survive for long.

"He was aggressive towards all of the other chimps," says anthropologist Michael Wilson of the University of Minnesota in Minneapolis, who first met Frodo in 2001. "A lot of the other males had a bare patch of fur on their lower back side from where Frodo would bite them."

Many other primates show similar behaviour to Frodo's. His actions hint at something rather dark about our shared ancestry with chimpanzees. They suggest that bullying your way to the top has a long history, and may even be innate.

Bullying is not easy to define, namely because there is no one way to bully. It comes in many forms, from physical playground scuffles to verbal attacks and, nowadays, online harassment.

It is pervasive in human society, having been reported across many different cultures. Psychologists frequently devote whole papers to its causes and consequences.

There is no legal definition of bullying. The UK government defines it as repeated behaviour with the "intent to hurt someone either physically or emotionally". Similarly, in a 2014 report, the Center for Disease Control and Prevention in the US defined bullying as: "any unwanted aggressive behaviour(s)…that involves an observed or perceived power imbalance and is repeated multiple times."

By those definitions there are many ape and monkey bullies. In fact, any hierarchical society is likely to have bullies in its midst.

This is strikingly obvious to anyone who has worked with rhesus macaques, a species of monkey with a rigid hierarchy. They engage in a behaviour that the primatologist Frans de Waal of Emory University in Atlanta, Georgia, calls "scapegoating".
An unfortunate monkey at the bottom of the hierarchy is repeatedly attacked and picked upon by those higher up in the group. They are sometimes beaten up every day, says de Waal.

"It seems to release tensions among the higher-ups," says de Waal. "That reinforces their bonds, as they have a common enemy." It seems to be an effective way to unite the more dominant macaques.

Removing the victim or "scapegoat" does not prevent the behaviour. The dominant macaques would simply turn on another low-ranking monkey. "When you're at the bottom, you're at the bottom, you get beaten up, that's how you live in that society," says de Waal.

Chimpanzees are similarly hierarchical.

To get to the top, alpha males often bully any chimp who stands in their way. "Chimps are 'natural bullies' and I have seen it often," says Richard Wrangham of Harvard University in Cambridge, US.

Bullying starts early. "Every male reaching adolescence starts his rise in the dominance hierarchy by teasing females," says Wrangham. Once a chimp has shown his power to all the females, he can challenge and fight other adult males.

Frodo is an extreme example. In his prime he was a ferocious hunter of monkeys, but also killed several other chimpanzees. He even snatched and killed a human child.

Alpha males like Frodo, Wilson says, are defined by their ability to outcompete others in any fight. "It's not like he's necessarily making decisions for [the] benefit of [the] group, he's doing what it takes to get what he wants, which is usually females."

The thing that defines this aggressive behaviour as bullying is that it is not immediately related to survival. In fact, it is often unprovoked, says Dario Maestripieri of the University of Chicago, Illinois. "Dominants attack subordinates out of the blue, for no apparent reason."

This unsolicited harassment may serve a useful purpose.

Maestripieri argues that bullying helps dominant animals to intimidate their subordinates, and that this has clear evolutionary benefits. It ensures that the dominant individuals have better access to food and to the opposite sex.

"The more a female is bullied by a particular male, the more that male gets to mate her. Sad but true," says Wrangham. "And we know it leads to him having more babies with her."

In line with this, a 2014 genetic study looked at the parents of all chimps born between 1995 and 2003, and revealed a direct link. Dominant and aggressive chimps fathered more offspring than their milder counterparts. It seems it makes sense for dominant members to spend so much time maintaining their status.

Even in captivity, where food is plentiful, bullying is still frequent in both rhesus macaques and chimps. "That means they [monkeys and apes] can invest more time and energy into maintaining their status," says Maestripieri. He says that is simply how they are wired.

It is not only primates who show bullying-like behaviours.

Chickens have a distinct "pecking order". As the term suggests, it is maintained by vicious pecking of those that step out of line.
More grotesquely, Nazca boobies sometimes bully young nestlings with unprovoked sexual attacks when their parents are away hunting for food. A 2008 study found that bullied boobies are more likely to become bullies when they grow older, perpetuating the cycle.

High-ranking spotted hyenas also bully their subordinates. This serves to "remind the latter of the power imbalance between them, and thus to maintain their superior social status," says Kay Holekamp of Michigan State University in East Lansing, US.

Bullying has even been observed in fish. For instance, male cichlids spend a lot of time beating up other males in order to ascend to a higher rank. One 2007 study revealed that male Astatotilapia burtoni can infer others' social rank just by watching fights. 

De Waal suspects that bullying can be found in any species in which hierarchy is important.

In a way this is not surprising. The tendency to take frustrations out on another is a "very basic mechanism", says de Waal. In some species, like chimps and humans, this "scapegoating" mechanism is simply more pronounced.

Being top-dog does not come without stress. Alpha males are often at risk of being overthrown by lower-ranking males.

If the hierarchy is unstable, as is often the case for baboons and chimps, those at the top are more stressed. However, in a more stable group the subordinates are the most stressed, presumably because they are frequently harassed.

Frodo was so big and dominant he may not have worried about usurpers, says Wilson. "Different males have different experiences depending how much bigger and stronger they are than the others. He could beat up everyone and frequently did."

However, bullying is not the only successful route to the top.

Frodo's brother Freud was leader before being ousted by Frodo, and he had a much more peaceful approach to leadership. In particular, Freud would groom others to form coalitions, something Frodo never did.

Perhaps because of his conciliatory approach, when Freud finally became weak he stepped down peacefully, and was accepted by the group as a lower-ranking male. In stark contrast, Frodo's downfall came quickly and violently.

In 2002, after five years of ruling, he became sick and weak. The cause was unknown. Noticing his reduced strength, the other males immediately attacked him.

Frodo spent the subsequent months alone, in exile. When he returned to his group he was demoted to a very low rank. He died in 2013, possibly from violent attack. His necropsy showed that his testicles were infected from a canine-shaped wound.

"In my experience the males who get there by bullying often end very badly," says de Waal. "In captivity they get attacked and we need to take them out. In the wild they get attacked and barely survive, or they get marginalised. The bullies are not very popular."

Nevertheless, from an evolutionary point of view this does not matter. Frodo fathered many offspring, and that means his genes – with whatever predispositions towards bullying they carried – have been passed on.

This seems to suggest a bleak conclusion. If so many creatures bully, perhaps bullying is innate in us, something we cannot escape. Is it, as the historian and philosopher Niccolo Machiavell famously wrote, "better to be feared than loved"?

We certainly seem to have the same scapegoating impulses as macaques and chimps, de Waal says. And powerful leaders do sometimes bully to get themselves into positions of power. Bullying is "a clear social strategy for self-advancement and power" in humans, says Maestripieri.

However, it is not quite that clear-cut.

Chimps are not our only close living relative. To understand how our behaviours evolved, we also need to look at another, often forgotten ape: the bonobo.

Bonobos are just as closely related to us as chimps. They have not been studied to the same extent, but they are known to be much less violent. They have even been dubbed "hippy apes" because of their peaceful nature.

In 92 years of study, Wilson and colleagues only discovered one instance of a "suspected death" in bonobo communities, contrasting with 152 possible murders in chimp groups.

Like bonobos, humans appear to have gone down a less violent path than chimpanzees. "It's rare to see direct physical aggression between [human] adult men in the same group compared to chimpanzees," says Wilson. "If you watch chimps for a day you are going to see aggressive reactions in the males. In humans it's more subtle."

As a species, we are more peaceful than chimps and less prone to impulsive violent outbursts. However, we also live in a society where competition with others is the norm. This pushes us towards using bullying as a social strategy.

"Human bullying is both the product of tendencies inherited from our chimp-like ancestors, and of competitive social environments like those of chimps and rhesus monkeys," says Maestripieri. "It's a double whammy."

In contrast, "bonobos live in social environments in which expressing bullying tendencies is simply not advantageous."

It is therefore not surprising that bullying is commonplace. In a busy school playground, you do not need to look for long before an unfortunate child is bullied.

In more subtle ways, adults also bully. There are many instances of workplace bullying and "psychopathic" bosses, while politicians use "scapegoating" to incite antagonism against minority groups. This approach "creates a common enemy when there are tensions in a society," says de Waal.

A 2013 genetic study revealed that the tendency to become a leader is at least partly genetic. In other words, some individuals are equipped with the personality traits to become group leaders, while others are more inclined to be followers.

At least some of these "natural leaders" will use aggression and bullying to maintain their status. Maestripieri also suspects that, if a person does not reach their social goal of becoming a "leader", it might lead them to bully more.

Still, bullying as a strategy may not lead to long-term success. Frodo's demonic approach to ruling clearly came at a cost. In line with that, a 2015 study suggested that ruthless people do not always get ahead.
Bullying may well have deep evolutionary roots. But if a leader wants to be accepted in the long term, they might do better to be loved than feared.

Melissa Hogenboom is BBC Earth's feature writer. She is @melissasuzanneh on Twitter.


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