Could Human Altruism Have Evolved Because of War?

By Eliza Strickland | June 5, 2009 10:35 am

cave paintingIt may sound like a paradox, but a new theory suggests that one of humanity’s most noble instincts, altruism, evolved on bloody battlefields in prehistoric times. Evolutionary biologist Samuel Bowles argues that prehistoric culture may have selected for individuals who behaved altruistically towards other individuals in their social groups. The story begins with the climactic swings that occurred between approximately 10,000 to 150,000 years ago in the late Pleistocene period may have pushed once-isolated bands of hunter-gatherers into more frequent contact with one another…. “I think that’s just a recipe for high-level conflict” [New Scientist], says Bowles.

These conflicts weren’t large-scale pitched battles, Bowles explains. “We’re talking about groups of men who got out in twos or threes or fives,” he says. “They didn’t have a chain of command and it’s hard to see how they could force people to fight.” For this reason, altruistic intent on the part of each warrior is key. Each person would do better to stay home than to put their life on the line for their neighbours – yet they still went out and risked their lives, Bowles says [New Scientist].

In the study, published in Science, Bowles set out to determine what would have happened to a group of altruistic individuals who had to fight other, more selfish tribes. According to his analysis of archaeological evidence from Stone Age sites and and ethnographic studies of remaining tribes, combat between groups accounted for about 14 percent of all deaths in hunter-gatherer societies…. After estimating the rate that altruism would reduce an individual’s chances of reproducing, Bowles plugged the numbers into a model of intergroup competition where an individual’s altruism would also improve a group’s chances of combat triumph. Groups with selfless individuals eventually predominated, and altruism predominated within those groups [].

Bowles stresses that his study is just a theory, and other experts stress that it’s a controversial one. Altruism is assumed to have some genetic root, but Bowles’ theory hinges on the idea of genetic group selection — selection for traits that are passed on because they benefit the group, even at a cost to individuals. Many biologists think this is, in practice, an unworkable process in human groups because they are not genetically distant or differentiated enough from each other for selection of group traits to occur [Nature News].

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Image: flickr / Raveesh Vyas

CATEGORIZED UNDER: Human Origins, Mind & Brain
  • Chris

    this strikes me as an extremely speculative idea.

  • Dennis

    >Bowles stresses that his study is just a theory

    “Hypothesis” – no wonder the average person doesn’t get the difference when scientists don’t make the distinction!

  • Skeptikor

    The idea may have more to support it than the article describes. If warrior individuals were seen as more attractive mates, they would have greater reproductive success. This could outweight the 14% mortality-from-war rate quoted (or whatever the actual percent might be). Additionally, in smallish or isolated populations over time, the altruistic characteristic could become fixed through genetic drift.

  • Nick

    Culture shapes human evolution.

    Western culture has allowed for the evolution of machines. That has made us self-select a sedentary, obese lifestyle.

    And this about this – some of our greatest myths involve altruism. Prometheus, the fire-bringer, stole knowledge from the gods to give to humans, but in doing so ruined his own life.

    This tale is probably an allegory of the many men who were involved with the taming of fire so long ago that they’ve become unto gods in the minds of the men who followed them. Many or most of the men involved with the taming of fire probably died playing with fire. But even though it was dangerous, hugely dangerous since before man tamed fire, only existingf as wildfires which would have put whole populaces at risk, men stepped up and conquered it for the good of the whole. And those who did it first and best would have better survival chances, thus teaching their tribe the value of altruism.

    Their genetic descendants have since conquered physics and quantum mechanics – displaying the same altruism that has made our collective human experience so dominant on this planet. Virtually none of the last century of human progress would have happened without quantum mechanics, and it wouldn’t have happened at all without the discovery and mastery of physics.

    But altruism is a very complex phenomena, involving future planning and empathy towards others… I don’t think we’ll find a very specific set of genes for altruism, I think in large part it is taught by society and family.

  • kyle

    the only altruistic act results in ones death, otherwise you gain something from the so called “altruistic” act even if it’s only the feeling of satisfaction one gets from helping someone out.

  • Albert Bakker

    @ Kyle: Well no, what you apparently refer to is selfish or reciprocal altruism and that is still altruism, regardless of a biochemical reward. For humans (among other animals) it translates into the abstraction of an iterated nonzero sum game ( that seems to always play out best for both using some form of a Tit for Tat strategy. This is rather well explained in Dawkins “The Selfish Gene” chapter 12 “Nice guys finish first.” I thought Susan Blackmore’s proposal to a memetic theory of altruism in “The Meme Machine” a nice follow up on that principle with the idea of selection of imitation. Yet another book, totally devoted to this subject based on the same sociobiological principle is Matt Ridley’s “The Origins of Virtue” And to mention at least one American author (which I greatly admire) I can’t yet say what Dennett makes of it in “Freedom Evolves” because I got kind of stuck in chapter 4, while making excursions to other subjects.

    I think, if true that “warriors” have this reproductive edge, Skeptikor has it backwards. I would think young and fit (symmetrical) men that already have reproduced because of these traits (were selected by women) are more likely to become warriors because of their motivation to protect their offspring/ genes. This would boil down to kin selection, the other way around to group selection.

    Instead this idea may just appear to be group selection, while that appearance that is easiest to observe might be an emergent feature risen from the aforementioned sociobiological principle.

  • zach

    This can become even more complicated if we take into account the Baldwin Effect. I know, heaping speculation onto speculation is pretty thin but what are these boards for if not extreme conjecture!? If groups that benefitted from altruism, wether in war or in sharing food in times of want, began to select for what was once a learned trait, and individual born with a predisposition for such action would be favored. In time this can lead to a once learned cultural trait becoming inherited. Before someone blasts me for being Lamarck, I am not saying that a learned trait will give rise to a genetic predisposition, just that if someone has a predisposition for what was previously only a culturally important trait, they have a massive advantage in that selective pressure. This can view is often attributed to the rise of language, which provides an enormous benefit that provides fertile ground for any individual propensity for the ability.

  • Jack

    but I always think of humans as fundamentaly “good” living beings.

  • zach

    What does it mean to be fundamentally good?

  • Yabba Dabba

    We were ahuntin and agatherin for many thousands of years before agriculture,beurocracy,armies came to be. Success depended upon cooperation between the tribe. That’s why women cycle together (so they can suckle a fallen sisters baby), why yawns are contagious (so the family group sleeps at the same time) and why we were able to eat those delicious Mastadon burgers that took 5 men to bring down. It’s also why war was best fought collectively. Altruism leant itself to all aspects of life. I don’t see its inception on a battle field- we couldn’t have been on the field at all if we didn’t do it as one!

  • kate sisco


    Competition for resources led to war. This seems like a historical revision to me.

  • Carmi

    Glad to see some other researchers taking a look at my ideas –

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