Evolution of Human Aggression.

[Existentialist1844]

Everyone has experienced anger at one point in their lives and some of us — males mostly, going by statistics — have channeled that anger into violence, perhaps by throwing a punch during a hockey game or after too many beers at the bar.
Then there's aggression on a much more sinister scale, in the form of murder, wars and genocide. Trying to understand what fuels the different levels of human aggression, from fisticuffs to nation-on-nation battle, has long preoccupied human biologists.

Is there evolutionary reasoning that explains our aggressive tendencies?

This is the central question that anthropologists are now asking as they meet this week at the University of Utah to discuss violence and human evolution. Speakers at the conference, "The Evolution of Human Aggression: Lessons for Today's Conflicts," intend to explore how the long process of human evolution has shaped the various ways we display aggression in modern society.

Though it may seem easier to divide the debate into two camps — those who think evolution has made humans naturally peaceful and those who think we're more naturally prone to violence, the real answer probably lies somewhere in between, said conference organizer Elizabeth Cashdan, professor of anthropology at the University of Utah.

"There is plenty of evidence to support both claims: violence, reconciliation, and cooperation are all part of human nature," said Cashdan, who thinks these wide-ranging emotions all evolved because they benefitted humans in some way in the past.

Animal instincts

Evolution can explain why humans exhibit aggression because it is a primal emotion like any other, experts say.

"Emotions (including revenge, spite, happiness, anger) must have evolved because most of the time they motivate fitness-enhancing behaviors, and that is surely true for humans as for other animals," said Cashdan.

Just as compassion for your offspring increases your genes' chance of survival, violent tendencies may have been similarly useful for some species, agreed biologist David Carrier, also of the University of Utah.

"Aggressive behavior has evolved in species in which it increases an individual's survival or reproduction and this depends on the specific environmental, social, reproductive, and historical circumstances of a species. Humans certainly rank among the most violent of species," Carrier said, adding that we also rank among the most altruistic and empathetic.

In true nature-nurture fashion, though some kind of genetic preprogramming for violence may exist in humans as a result of our evolution, it is the specific environment that decides how, or whether, that biological determination is triggered, scientists say.

"Biologists speak of 'norms of reaction,' which are patterned responses to environmental circumstances. For example, some male insects are more likely to guard their mates when there are fewer females in the population, hence fewer other mating opportunities. Natural selection didn't just shape a fixed behavior, it shaped the norm of reaction — the nature of the response," said Cashdan.

In other words, though aggression for aggression's sake is rare, an intricate set of conditions could, conceivably, drive most people to violence.

Instead of competing for food, which has become relatively easy to attain in most parts of the world, today we compete for material resources, said Cashdan, and some individuals lack or lose that switch that tells us when enough is enough. Gang violence is a good example of competition for resources gone haywire, though while a gang member's desire for more things, money or partners causes problems now, it may have been the key to their survival 100,000 years ago.

Our emotions make us unique

While human aggression is a naturally evolved phenomenon we have in common with other animals, the difference between human and animal violence comes down to the complexity of the emotion driving it, said Cashdan.

"Humans are unique in the complexity of their social relationships and their highly developed social intelligence. Revenge and spite are quintessential social emotions and so are not likely to be found in many, if any, other species," she said.

Aggression in few animals goes beyond protecting one's territory, mates, offspring and food — there is some evidence that domestic dogs and chimpanzees do hold grudges, said Carrier — but human violence has evolved to stem from less typical sources.

"For example revenge killings, and the cultural institutions that support and restrain it,
shape human aggression in new ways," said Cashdan. The intelligent reasoning that lets most of us override any innate desire to be violent also makes some people, such as parents that kill their children, as well as institutions justify violence illogically, experts say.


Worry over the future

An understanding of the evolutionary roots of human aggression could help institutions make better policy decisions, according to experts.

"Evolution didn't just shape us to be violent, or peaceful, it shaped us to respond flexibly, adaptively, to different circumstances, and to risk violence when it made adaptive sense to do so. We need to understand what those circumstances are if we want to change things," said Cashdan.

Though conflicts like the ones that occurred in Rwanda and the former Yugoslavia in the 1990s may seem a distant memory, the tipping point between peace and that sort of violence is a finer line than we think, said Carrier.

"My personal opinion is that Western society, as a whole, is in mass denial about the magnitude of the problem that violence represents for the future. We are peace-loving and want to believe that the violence and transgressions of the past will not return, but recent history and current events illustrate how easy it is for humans to respond with interpersonal and intergroup violence," he said.

This will be especially important in places where key natural resources are becoming scarce, said Carrier, who warned that "if basic resources such as food and clean water become more limiting, as many scientists believe is likely to happen as a result of climate change and energy shortages, then the environmental and social drivers of violence may become more difficult to control."

[soul_biscuit]

Nice article! Where'd it come from?

There is plenty of evidence to support both claims: violence, reconciliation, and cooperation are all part of human nature," said Cashdan, who thinks these wide-ranging emotions all evolved because they benefitted humans in some way in the past.

This is the crux of it, I think. Violence is a part of what our evolutionary past has made us, and so is peace. Violence combined with our ingrained "in-group/out-group" mentality kept different bands of humans distinct, and drove humans of one band to defend themselves against other bands. In light of this, it's remarkable how peaceful many modern humans are able to be in our world of massive, continent-spanning nations.

[Existentialist1844]

In true nature-nurture fashion, though some kind of genetic preprogramming for violence may exist in humans as a result of our evolution, it is the specific environment that decides how, or whether, that biological determination is triggered, scientists say.

I am reading On Human Nature by EO Wilson. He tries to explain behavior through biological mean, which he calls sociobiology. Basically, he argues that we are all predisposed for language, to form in and out groups, etc. How language and group formation is manifested is determined by environmental means. For example, Wilson states that it is no coincidence that most of us develop language at the same time and in such a short period after birth. Obviously, there has to be some genetic predisposition for language. How its manifested is determined by culture. This is akin to Noam Chomskys Language Acquisition Device (The Language Acquisition Device (LAD) is a postulated "organ" of the brain that is supposed to function as a congenital device for learning symbolic language (i.e., language acquisition). First proposed by Noam Chomsky, the LAD concept is a component of the nativist theory of language which dominates contemporary formal linguistics, which asserts that humans are born with the instinct or "innate facility" for acquiring language.)

Same thing with the above statement. We are all predisposd to aggression, but how its manifested is determined by the cultural in which you are raised.

[soul_biscuit]

Same thing with the above statement. We are all predisposd to aggression, but how its manifested is determined by the cultural in which you are raised.

I like that. I haven't read any of Wilson, but he featured in a recent NPR interview I listened to, so I looked him up online. I'll have to read Sociobiology.

Nowadays his ideas seem to have been inherited by evolutionary psychology, which despite its problems is a fascinating field. I look forward to some interesting discoveries.

[Gawdzilla Sama]

Aggression. Now that's something I know a little about.

[soul_biscuit]

Aggression. Now that's something I know a little about.

I should think so! Any insights?

[Existentialist1844]

Aggression. Now that's something I know a little about.

No derails!

[Gawdzilla Sama]

Aggression. Now that's something I know a little about.

No derails!

Who's derailing? I know human aggression first hand.

[Existentialist1844]

Aggression. Now that's something I know a little about.

No derails!

Who's derailing? I know human aggression first hand.

Thats fine, but state your observations to help move the discussion along. Naturalistic observations are a form of studying people. Not the most reliable, but its used quite often by animal behaviorists.

[Gawdzilla Sama]

Aggression. Now that's something I know a little about.

No derails!

Who's derailing? I know human aggression first hand.

Thats fine, but state your observations to help move the discussion along. Naturalistic observations are a form of studying people. Not the most reliable, but its used quite often by animal behaviorists.

I observed that its easier to get people to kill other people when they fear them rather than hate them. Empirically, hate doesn't justify killing as easily as fear does.

[Existentialist1844]

Aggression. Now that's something I know a little about.

No derails!

Who's derailing? I know human aggression first hand.

Thats fine, but state your observations to help move the discussion along. Naturalistic observations are a form of studying people. Not the most reliable, but its used quite often by animal behaviorists.

I observed that its easier to get people to kill other people when they fear them rather than hate them. Empirically, hate doesn't justify killing as easily as fear does.

Thats because fear is a primal instinct that is related to the threat of owns existence. If emotions are deeply rooted, hate would be something that wouldnt have been beneficial for our ancestors. Hunting in large groups would be dependent upon cooperation and understanding, not hate. On the other hand, our ancestors had an abundance of things to be afraid of which threatened their existence. Kill or be killed. Thus, I surmise thats why its easier to get someone to kill someone else based off of fear and not hate.

[Horwood Beer-Master]

[Blind groper]

To Gawdzilla

You are a Viet Nam veteran. However, I suspect what I am about to tell you is something you already know.

An American study in WWII showed that 85% of soldiers are so reluctant to kill, that in the middle of a fire fight they will fire into the air or not fire at all. Naturally, this reduced their effectiveness as soldiers! The 15% that did shoot at the enemy would be a mixture of those who were psychopaths, almost psychopaths, or so fixed on their duty they did what their instincts told them not to do.
http://progressive.org/mag/boudreau0209.html

I quote :

"There was a well-known study—well known within the military, anyway—done directly after World War II by retired Colonel S. L. A. Marshall, author of Men Against Fire: The Problem of Battle Command in Future War. He discovered that even in the thickest of fire fights, the vast majority of soldiers did not fire their weapons. (Based on interviews with the soldiers themselves, Marshall estimated that within the average unit under fire, only 15 percent of men actually pulled their triggers. Even within the most disciplined units, he found that average rose to not more than 25 percent.) Marshall discovered that it was not fear that prevented these men from engaging their enemies, but humanity. All of them reported a keen reluctance to kill."

Since that time, the various training departments of armies round the world have changed their training systems in order to raise the percentage of soldiers who actually shoot at the enemy. The first successful training system like this was American. and applied to those soldiers who went to Viet Nam. So, Gawdzilla, it is very likely you have a jaundiced view of human violence, since you were among those first soldiers to be trained to kill.

There is, of course, a price to pay. The reluctance to kill another human is merely submerged, not surgically removed. Those decent people who kill due to that training, rather often experience deep feelings of guilt which can remain with them all their lives. This is one of the major causes of post traumatic stress disorder among returned vets.

I find this reluctance to kill to be an uplifting thought. Most people are not 'natural born killers', but the reverse. Most people do not want to harm others, and will refrain from doing so, even under the provocation of a massive fire fight in battle.

[Gawdzilla Sama]

BG, those figures have be studied and rejected as unfounded.

[Gawdzilla Sama]

BTW, we didn't want people that would happily kill other people, they're psychotic. We wanted people we could trust next to us in a fire fight.