Evolutionary origin of wars

From: Keith Henson (hkhenson@rogers.com)
Date: Sat Mar 27 2004 - 16:11:31 MST

At 05:07 AM 27/03/04 -0500, you wrote:
>From: Keith Henson <hkhenson@rogers.com>
> >The problem is that win or lose war was adaptive for your genes when we
> >lived as hunter-gatherers. Thus we have evolved psychological mechanisms
> >that lead to tribes (or nations) going to war based on economic
> >issues--currently income per capita though the origin of the mechanism was
> >game and berries.
>Aggressiveness probably evolved much earlier in phylogeny.

Agreed, but aggressiveness is *not* war. War is an emergent phenomena
where one social group attacks another.

>I'm not sure how much new genetic traits have accumulated
>specific to primates or hominids.

It is clear from Jane Goodall's work (and related studies) that wars
resulting in genocide of neighboring groups is something chimpanzees
do. That makes it likely, though not certain, that wars between groups of
hominids dates back to the time of the split.

> >Humans who are not facing looming privation/starvation don't start wars,
> >though they can still be attacked by those with the root cause.
>Then how do you account for imperialism where it's the
>powerful nations that initiate wars?

First, be specific, *which* war? Second, evolutionary adaptions made when
our ancestors lived as hunter-gatherers can't be expected to be
particularly adaptive in world so far removed from the Environment of
Evolutionary Adaptedness (EEA)


I used "looming privation" above. Because humans (and animals in general)
respond to differences, you can soak one hand in hot water and one in cold,
then put them both in warm water. The hand that was in the hot water will
find the warm cold and the one that was in the cold will find the same
water hot. Thus you don't need actual starvation; gloomy economic outlooks
for a people that had been doing well are enough to trip xenophobic meme
buildups leading to war or related social disruptions.

Robert Cialdini talks about *relative* economics in _Influence_ as a cause
for wars and related social unrest such as riots. He cites James C. Davis
on this topic:

      "The idea that newly experienced scarcity is the more powerful kind
applies to situations well beyond the bounds of the cookie study. For
example, social scientists have determined that such scarcity is a primary
cause of political turmoil and violence. Perhaps the most prominent
proponent of this argument is James C. Davies, who states that we are most
likely to find revolutions where a period of improving economic and social
conditions is followed by a short, sharp reversal in those conditions. Thus
it is not the traditionally most downtrodden people-who have come to see
their deprivation as part of the natural order of things who are especially
liable to revolt. Instead, revolutionaries are more likely to be those who
have been given at least some taste of a better life. When the economic and
social improvements they have experienced and come to expect suddenly
become less available, they desire them more than ever and often rise up
violently to secure them.

      "Davies has gathered persuasive evidence for his novel thesis from a
range of revolutions, revolts, and internal wars, including the French,
Russian, and Egyptian revolutions as well as such domestic uprisings as
Dorr's Rebellion in nineteenth-century Rhode Island, the American Civil
War, and the urban black riots of the 1960s. In each case, a time of
increasing well-being preceded a tight cluster of reversals that burst into

This response is exactly what you would expect to have evolved in
hunter-gatherers faced with a periodic requirement to reduce their
population in the face of ecological fluctuations.

> >The economic connection to wars is *very old* information. But it is the
> >first time I know about that the evolutionary psychology origin of wars has
> >been understood. It leads to obvious solutions, but they are slow to take
> >effect.
> >Here's a question for you. If the population simply *had* to be cut way
> >back (say due to an ice age starting) would war or disease be the better
> >choice?
>I don't understand what you're trying to imply, but if I die
>of disease then my 'kinsman' (people genetically related to me)
>would be most likely to inherit what I've left over.

Perhaps, though if your shared genes were part of the reason they were
killed by an epidemic, there might not be anyone related to
inherit. That's what happened when European diseases (such as measles)
wiped out the Mound Builders in the Mississippi Valley.


>in a war and if I lose then my assets will be taken by the
>enemy, resulting in loss of territory. It would be a very
>strange theory if you're saying people start wars unconsciously
>hoping to lose and to have their women marry off the winners.

That's an incorrect oversimplification of what I am saying. Economic
reasons (originally access to food resources) are the deep gene based
reasons people start wars.

Wars were *conditionally* advantageous to genes. In good times with plenty
to eat, your genes were much better off raising kids with copies of those
genes than getting in group fights with hostile neighbors where you and
your genes may both come to a sorry end. So genes build human with a
normal thinking bias we call "rational" and we stay out of such fights most
of the time.

But when enough people are successful in raising those kids, the
environment eventually becomes overloaded and/or there is a glitch in the
weather. Now these brains built by genes have to switch to an alternate
behavior, move to new lands (normally impossible in a filled up world) or
fight neighbors for their resources. This is necessary but it is (using a
rational mind state) obviously dangerous.

The genes overcome the normal rational bias against putting yourself in
danger of being killed by creating brains with the psychological trait of
responding to and spreading xenophobic memes when times start looking
bad. Indeed, the word I coined back in 1985 of "memeoid," is
appropriate. (". . . victims that have been taken over by a meme to the
extent that their own survival becomes inconsequential.")

Groups who start wars--especially where they people they are fighting are
more numerous--are optimistic over their prospects to prevail. Outsiders
would call a lot of them deluded.

Where the young women come in is through Hamilton's inclusive fitness
criteria. They have copies of the genes of the warriors who go off to
glory or death. In tribal days (when all this selection happened) the
winning tribe usually killed the males of the losers and took the women,
thus preserving genes that build brains capable of spreading xenophobic
memes and entering the deluded state needed to go to war.

Keith Henson

PS Writing came along toward the end of the tribal era so some of our
early written records discuss this common practice. For example Numbers
31:18. "But all the female children who have had no sex relations with
men, you may keep for yourselves." and
Deuteronomy 20:13-14 When the LORD your God hands it over to you, kill
every man in the town. But you may keep for yourselves all the women,
children, livestock, and other plunder.

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