Thursday, July 30, 2009

Genetic pacification? Part II

Natural selection has altered at least 7% of our genome over the last 40 thousand years. And it has been doing so at an accelerating rate, particularly after agriculture replaced hunting and gathering less than ten thousand years ago. At that time, the rate of genetic change may have risen over a hundred-fold (Hawks et al., 2007).

By then, our species had colonized almost every ecological niche on the planet—savanna, tropical rain forest, temperate woodland, boreal forest, and arctic tundra. It wasn’t because we were entering new ecological environments that genetic change speeded up. It was because we were entering new cultural environments.

One of them arose with the emergence of the State and its monopoly on the use of violence. This marked a sea change in human relations. Previously, men often used violence for their own advancement, and not simply in self-defense. The goal was to become a ‘big man’—someone who could dominate the local community through bluster, bullying, and charisma. Such men were more successful not only socially but also reproductively. They tended to attract more mates and sire more children.

The tables were turned with the rise of State societies. Over large territories, power increasingly fell into the hands of a few big men, often only one, and violence became a privileged instrument of their power. This left all other men with three options:

1. Forsake violence, or at least keep it under the radar screen of State detection.
2. Subordinate it to State goals, i.e., join the army.
3. Embrace it and become outlaws.

Thus, within the borders of Statist societies, survival and reproduction came to depend on one’s willingness to comply with the State, including its monopoly on the use of violence. Successful individuals were now those who had a higher threshold for expression of violent behavior, especially when acting on their own initiative. They also tended to be individuals whose relative inhibition of violence could be released only by the voice of authority. (In modern times, an American psychologist found that people are much likelier to inflict violence when told to do so by an authority figure. Does this finding hold true in all human societies? see Milgram, 1974).

This change in cultural environment is described by Liebeschuetz (2006) when he discusses Roman and barbarian societies:

In Roman law violence against individuals was treated as an offense that concerned the community. It was open to every citizen to launch a prosecution. The state provided the courts that established whether an injury had been inflicted, decided the punishment, and inflicted it. Moreover the imperial mandate to provincial governors stated, “The man in charge of a province must see to it that he clears the province of criminals.” Ulpian explains this as meaning:

“It is the duty of the … governor to see that the province he rules is peaceful. … This he will achieve if he takes careful measures [to ensure] that the province is free from criminals and searches them out. He should search out persons guilty of sacrilege, brigands, kidnappers, and thieves and punish them according to their offenses, and he should also repress them that harbor them.” (Liebeschuetz, 2006, p. 40)

In contrast, barbarians took the law into their own hands. Although law courts existed in Germanic society, their rulings had to be enforced by the aggrieved party. There was no State enforcement:

The injury was treated as an offense against the injured and his kin and it was left to the injured and/or his kin, not to the community, to compel the person who had caused the injury to give compensation for the damage he had inflicted. Unless the perpetrator or his kin paid compensation, it was the duty of the victim or his kin to take vengeance on the perpetrator or his kin. But the use of force was likely to start a chain of retaliation, in fact a feud. (Liebeschuetz, 2006, p. 39)

The threat of the feud might well have secured a reasonably stable society. But it certainly depended on a widespread readiness to answer violence with violence. It was, I would suggest, a society in which the private individual would have been more likely to have to act violently or to have experienced violence inflicted by others than he would have under Roman administration. (Liebeschuetz, 2006, p. 46)

Historiography often assumes that the Romans saw the divide between themselves and barbarians as a matter of learning and education. To a large degree, this assumption reflects a 20th century view that such a divide had to be culturally programmed. After all, many of the barbarians went on to become civilized Europeans. The picture is less clear, however, if we go back and read what Romans writers had to say. Many considered the divide to be rooted in nature:

Both explicitly and implicitly late antique writers created a generic barbarian identity that was intimately associated with violent behavior. This was only consistent with a classical literary tradition in which barbarians were associated with several violence-related traits, including crudelitas (cruelty), feritas (wildness), immanitas savagery), inhumanitas (inhumanity), impietas (impiety), ferocitas (ferocity), furor (fury), and discordia (discord). (Mathisen, 2006, p. 28)

Their violent nature also meant that barbarians were thought to be governed by their emotions rather than by their intellect. Seneca could claim that grief particularly affected “barbarians more than persons of a peaceful and learned people” and that barbarians were more likely to become angry. He also commented on barbarian lack of self-control: “Whom does one admire more than one who controls himself, who has himself under control. It is easier to rule barbarian nations and those impatient of alien rule than to contain and control one’s own mind.” Finally, Libanius suggested, “In this regard in particular I find the Greeks also to be superior to barbarians. The latter are akin to beasts in despising pity, while the Greeks are quick to pity and get over their wrath.” (Mathisen, 2006, p. 30)

To be sure, some believed that the barbarians could assimilate to Roman norms of behavior. In the 4th and 5th centuries, large numbers of them were allowed into the Empire and confident predictions were made that they would turn their swords into ploughs and scythes (Mathisen, 2006, p. 33). Events proved otherwise.

Like many of my readers, I am largely descended from barbarians who destroyed Roman Britain in the 5th century (Shaw, 2009). Maybe “destroyed” is the wrong word. They didn’t intend to destroy anything; they just wanted the same sort of things that the Romans had. Unfortunately, by their very presence, they made the continuation of those things impossible. Civilization was eventually rebuilt, but on a new foundation.

How did they become me? It was a long process stretching over some sixty generations. Like others before them, they too went on to create their own States. These States then strove to monopolize the use of violence, thus setting in motion the same behavioral evolution that has happened elsewhere.


Hawks, J., E.T. Wang, G.M. Cochran, H.C. Harpending, & R.K. Moyzis. (2007).
Recent acceleration of human adaptive evolution. Proceedings of the National Academy of Sciences (USA), 104, 20753-20758.

Liebeschuetz, W. (2006). Violence in the barbarian successor kingdoms, in: Drake, H.A. (ed.) Violence in Late Antiquity. Perceptions and Practices, pp. 37-46, Burlington (Vermont) and Aldershot: Absgate.

Mathisen, R.W. (2006). Violent behavior and the construction of barbarian identity in Late Antiquity, in: Drake, H.A. (ed.) Violence in Late Antiquity. Perceptions and Practices, pp. 27-35, Burlington (Vermont) and Aldershot: Absgate.

Milgram, S. (1974). Obedience to Authority. New York: Harper & Row.

Shaw, J. (2009). Who killed the men of England. The written record of history meets genomics, evolution, demography, and molecular archaeology. Harvard Magazine, July-August.,1


Tod said...

The change was rather late for a gradual reduction in those with violent propensities:-
Eisner 2001

"The results confirm, first, that homicide rates have declined in Europe over several centuries. Second, the empirical evidence shows, that unequivocal decline began in the early seventeenth century. Third, the data indicate that the secular decline begins with the pioneers of the modernization process, England and Holland, and slowly encompasses further regions".

An incremental reduction in the specific propensity to be violent over many generations would surely result in a similarly incremetal reduction in homocide over the generations; not the late drop. The fall in homocide may have resulted from the then novel effectiveness of law enforcement making potential perpetrators assess violence as being too costly a course of action.

The abilty to control emotions - effortful control - would surely be as necessary for a barbarian warrior as an Englishman engaged in peaceful family business. A warrior would not last long without being careful who he picked on and that would not just apply to the immediate obvious - " too big to fight"; the considerations would also take into account things very like legal consequences -"he has several brothers who would lose all respect unless they take revenge" - and so on.

Peter Frost said...


Even if one assumes a constant selection pressure to reduce violence, it doesn't follow that a linear downward trend will be the result.

For instance, blood sports used to be popular in England. They were banned once a sufficiently large proportion of the population considered them to be repugnant. I'm sure there are still English people who love the sight of blood, but they are now a minority. At one time, they were the majority.

I also suspect that the selection pressure was not constant. Is it just coincidence that the acceleration of this downward trend corresponds to the surge in English and Dutch birth rates between the early seventeenth and mid-nineteenth centuries? The baby boom occurred mainly among families engaged in cottage industries. During this phase of early industrial capitalism, successful entrepreneurs expanded their work forces by having larger families. Most of them belonged to dissident Protestant sects (Quakers, Plymouth Brethren, Methodists, etc.) and, as such, rejected violence, often to the point of embracing pacifism.

I'm not sure why these early industrialists were more opposed to violence than the rest of the population. Perhaps pacifism was an ideological side-effect of selection for more harmonious economic transactions.

On your second point, there's a difference between self-control and readiness to engage in violence. It's possible to have a highly developed sense of self-control while being ready to inflict violence at the drop of a hat. This is what we see, for instance, in mountainous areas of Afghanistan. The use of violence is regulated by a large number of social rules. But the rules no longer apply once you step outside them, even inadvertently.

Anonymous said...

This post and the preceding one were outstanding, nice job.

Henry Harpending said...

Excellent, Peter. I would also suggest that at the very low end of subsistence, Bushmen or Shoshone, everyone was too busy trying to get enough to eat to find any payoff to violence. Violent !Kung are essentially executed by the groups, i.e. lynchings.

Would be interesting to know what the Crow and Sioux and Comanche were like before the horse showed up.

Henry Harpending

Tod said...

That the association between falling violence and a surging birthrate in England was being paralleled in Holland is doubly convincing.

A lot of violence is domestic, maybe succesfully raising the larger families intensified selection for 'caring and sharing' temperaments.

Peter Turchins in War and Peace and War says Rome lost infuence because the Legions came to be only 10% Roman; those from the Empires core area didn't want to join up. So it could be said that the prudent non-violence that came to characterize the Romans - being the main reason for barbarians being accepted into the empire - was their downfall.

Subcomandante Dave said...

Two guys have a beef and decide to settle it with either a fistfight or a duel; is this any of the state's business? Generally, I think not. I never did like the "monopoly on violence" definition of the state.

Keegan in A History of Warfare argues that both fistfights and duels are fairly unique to Western European countries and are a fairly ingenious form of co-operation, somewhat counter-intuitively. In most other cultures there is the cycle of violence, one guy insults another guy, that guy initiates violence, the other guy and his brothers retaliate, the first guy and his cousins retaliate against the brothers, etc. etc. Duels and fistfights put and end to the cycle of violence and serve a Darwinian purpose.

I'd like more violence in society. A prohibition on violence leads to unaccountability and incivility, and can lead to a dictatorship of the weak, or mouthy punks at any rate, over the strong, which seems to violate natural law. Does the concept of dysgenics not come into play when the strong are prohibited from using their gifts, and the mouthiest and most insulting are most able to reproduce?

The state may have an interest in prohibiting or controlling violence because if the cycle of violence gets out of control eventually the menfolk are depleted. Taken too far, though, it leads to a situation as in my unfortunate duckburg: incivility, knowing that the state will intervene on behalf of the mouthy little shit who runs his mouth off.

They say an armed society is a polite society but a violent society may be more accurate. When the state too jealously guards its monopoly on violence there is less incentive to be polite. It's odd and somewhat anomalous that libertarians tend to be against violence, with the whole "my right to throw a punch ends at the tip of your nose" spiel. I'd respond that your right to insult me, and thus lower my social status leading to real, tangible material loss including harming my ability to find/keep a mate, ends at the beginning of my ear canal.

On another tangent, I've read that women are selecting for less sexual dimorphism, and that incisor teeth are getting smaller.

Excellent series of posts, btw.

Subcomandante Dave said...
This comment has been removed by the author.
Peter Frost said...


Thanks for your comments!

There seems to be more selection for violence in early agricultural societies (with little or no State formation) than among hunter-gatherers. For instance, the agricultural Iroquoians were more violent than the hunter-gatherer Algonkians. In short, the creation of a storable food surplus tends to increase the potential for social equality and the accompanying struggles for power.


You raised a point I hope to address later. Because States seek to monopolize the use of violence, they diminish the pool of people who make suitable soldiers. So they end up recruiting barbarians who end up becoming a threat to the State.

Subcomandante Dave,
"Two guys have a beef and decide to settle it with either a fistfight or a duel; is this any of the state's business?"

Gentlemanly fights are not the typical expression of non-State violence. Usually, the strong beat up on the weak and the many beat up on the few. That has been my personal observation.

It's not simply out of fear for its own power that the State monopolized the use of violence. Violence is inimical to prosperity and progress.

Tod said...

GNXP on homocide rates.

The data are homocides per 100,000 of the population. Sorry if it's a stupid question but - is the age structure of the population(s) being taken into account? You don't have to be Gunnar Heinsohn to think violence per 100,000 pop. will be greater 15- 29 years after a baby boom, even with the same genetic characteristics.

Tod said...