Tuesday, April 20, 2010

Cooperation Among the Chaldeans

Why do humans cooperate?

That question is particularly puzzling when we consider large-scale political communities in which hundreds of millions of individuals cooperate with one another in complex ways, although most of these individuals are strangers to one another.

Of course, we could also ask, Why do humans fail to cooperate? After all, every community falls short of perfect cooperation, and the history of every community shows disruptive and often violent conflict.

We all benefit from living in cooperative communities. But as individuals, it might seem to be in our self-interest to become free-riders, who enjoy the benefits of a cooperative society without bearing any of the costs. This dilemma runs through the history of political philosophy and the social sciences.

It's the problem conveyed in the "ring of Gyges" story in Plato's Republic: if I could become invisible whenever I wished, would I be tempted into committing the greatest acts of injustice, while maintaining the reputation of a just man, and thus avoiding punishment for my injustice? If I yielded to such temptation, and safely hid my injustice from others, would I still suffer the punishment of having the disordered soul of an unjust man?

By what principles of justice should we rightly determine the standards of cooperation? Is just cooperation whatever serves the common good of any community? Or would such subordination to the common good violate the private good of individuals with diverse abilities and propensities? If just cooperation serves the common good, how do we settle conflicts between different groups or communities with different conceptions of the common good? Is there some natural standard of perfect justice in the best regime? Or is all justice conventional as varying for differing communities with different traditions and customs of cooperation?

Darwinian theories of the evolution of cooperation attempt to answer some of these questions. Over the past 25 years, proponents of evolutionary psychology (such as John Tooby and Leda Cosmides) have stressed the evolved human nature of cooperation as shaped genetically in the prehistoric circumstances of the "environment of evolutionary adaptation" (EEA). Their critics charge that this reliance on biological explanations fails to see the importance of cultural explanations.

Recently, advocates of gene-culture coevolutionary theory have argued that this dichotomy between biology and culture is mistaken, because the full explanation of human social life requires a complex combination of genetic and cultural factors. In taking this position, they are reviving Darwin's evolutionary approach to human social and moral behavior, which saw human life as manifesting the interaction of biological and cultural evolution.

One of the leading exponents of this coevolutionary reasoning is Joseph Henrich. As a graduate student in anthropology at UCLA, Henrich's mentor was Robert Boyd. Much of Henrich's work has been extending the tradition of research begun by Boyd and Peter Richerson in their book Culture and the Evolutionary Process (University of Chicago Press, 1985), which showed how social learning could be understood as a genetically evolved adaptation for learning adaptive traits in complex and variable environments. This requires a broad evolutionary approach that studies not only genetic evolution but also cultural history and the coevolution of genes and culture.

This approach was first suggested in Darwin's Descent of Man. Darwin thought that human morality had advanced more through cultural evolution than by natural selection, although the capacity for cultural learning and sympathy for social approbation and disapprobation had evolved by natural selection. Darwin wrote:

"The moral nature of man has reached its present standard, partly through the advancement of his reasoning powers and consequently of a just public opinion, but especially from his sympathies having been rendered more tender and widely diffused through the effects of habit, example, instruction, and reflection. It is not improbable that after long practice virtuous tendencies may be inherited. With the more civilized races, the conviction of the existence of an all-seeing Deity has had a potent influence on the advance of morality. Ultimately man does not accept the praise or blame of his fellows as his sole guide, though few escape this influence, but his habitual convictions, controlled by reason, afford him the safest rule. His conscience then becomes the supreme judge and monitor. Nevertheless the first foundation or origin of the moral sense lies in the social instincts, including sympathy; and these instincts no doubt were primarily gained, as in the case of the lower animals, through natural selection" (Penguin Books edition, p. 682).

This idea "that after long practice virtuous tendencies may be inherited" manifests the Lamarckian element in Darwin's thought. In another passage, Darwin speaks of "natural selection, aided by inherited habit" (155). This seems to be Darwin's anticipation of what James Mark Baldwin later called "social heredity": social evolution creates a cultural environment to which genetic evolution adapts. As Henrich and many others have noted, this "Baldwin effect" has been confirmed in some famous cases--as in the genetic evolution of lactose tolerance in adults in response to a cultural history of dairying. It is possible, then, that if cultural traditions of moral virtue were stable over a few thousand years, this could have created a selective pressure favoring genetic adaptations for such moral learning. This is the coevolution of genes and culture.

To my mind, the best single statement of this coevolutionary study of human culture is the book Joseph Henrich coauthored with his wife Natalie--Why Humans Cooperate (Oxford University Press, 2007). The book is especially rich in its combination of many research strategies--theoretical modelling of evolution, behavioral experiments in economic games, and an anthropological case study--to show the evolution of human cooperation.

The case study concerns the Chaldeans of metropolitan Detroit. The Chaldeans in Detroit are Catholics from Iraq who believe themselves to be descendants of the Chaldean civilization of ancient Mesopotamia. The Chaldeans might date back as far as 11,000 years. A Chaldean dynasty ruled over Babylon from 625 B.C. to 482 B.C. Chaldeans believe that Judaism, Christianity, and Islam are all traced back to the Chaldeans through Abraham, because Abraham was said in the Bible to have lived in "Ur of Chaldea" (Genesis 11:31). Since the beginning of the 20th century, the Chaldeans have migrated to the Detroit area, seeking economic opportunity and freedom from persecution in Iraq. They have prospered in Detroit because almost all of the small grocery stores in Detroit are owned by Chaldeans.

The Henrichs show how the Chaldeans illustrate the simple core principle in the evolution of cooperation. "Cooperation can evolve under circumstances in which selection takes advantage of a stable regularity that allows cooperators to preferentially bestow their benefits on other cooperators; in other words, cooperation can evolve when cooperators tend to cooperate with other cooperators" (42).

The dilemma of cooperation could be solved if there were a gene causing those with it to have green beards and to help only others with green beards. These green-bearded cooperators could cooperate with one another with no fear of being cheated by free-riders. This would solve the "Ring of Gyges" problem, because cheaters could not disguise themselves as cooperators. But this would fail if there were a mutant green-beard gene that did not make its bearer cooperative.

So, the problem for the evolution of cooperation is how to arrange the circumstances of cooperation so that cooperators could increase the probability of their cooperating with other trustworthy cooperators, while identifying and punishing those who were untrustworthy.

The Henrichs identify five evolutionary solutions to this problem: (1) kinship, (2) direct reciprocity, (3) indirect reciprocity enforced through reputation, (4) social norms enforced through third-party punishment, and (5) ethnicity. All five of these evolutionary grounds for cooperation were recognized by Darwin. All five have been confirmed by recent research in evolutionary modelling and in experimental games. And all five are illustrated in the social life of the Chaldeans.


The most common forms of cooperation in nature are parental care of offspring and care of one's kin in general. This solves the problem of cooperation because one's close kin are more likely to be trustworthy cooperators than those who are not kin.

Darwin saw that the social instincts of animals, including human beings, were largely extensions of parental care and kinship.

Universally, human beings tend to reserve their most costly forms of cooperation for close kin. Tooby and Cosmides and other proponents of evolutionary psychology argue that this can explain cooperation in modern large-scale societies, because the human propensity to aid kin, which evolved genetically in the Pleistocene era, can be tricked in modern environments so that we care for nonkin as if they were kin. But the Henrichs rightly challenge this by pointing out that human beings are quite good at distinguishing close kin from distant kin and nonkin. For example, as the Henrichs point out, 86% of kidney donations in the United States come from close kin, while only one-half of one percent come from anonymous strangers.

And while the Chaldeans say that all Chaldeans belong to the same community as one family, their behavior shows clear lines separating kin from nonkin, so that Chaldeans are much more likely to provide costly aid to close kin than to those who are not.

The history of utopian communities--from Plato's Republic to modern socialist communes--shows the failure of the attempts to extend kinship cooperation to embrace nonkin in the same community so that private families and private property can be abolished.


As Robert Axelrod showed in The Evolution of Cooperation (1984), one solution to the problem of cooperation is direct reciprocity based on a strategy of tit-for-tat exchange, because this allows us to cooperate with other cooperators while punishing those who are cheaters.

Darwin saw the importance of direct reciprocity as a ground for cooperation and morality among humans: "as the reasoning powers and foresight of the members become improved, each man would soon learn that if he aided his fellow-men, he would commonly receive aid in return" (156).

But unlike kinship, such direct reciprocity is rare in the rest of nature. The Henrichs explain how human culture allows human beings to solve the problems of reciprocal cooperation that most other animals cannot solve. For example, language and writing allow us to keep records of our direct exchanges with others to make sure we are not being cheated.

The Chaldeans have found ways to monitor exchanges to insure reciprocal fairness. For example, they have a system by which people attending weddings and funerals leave cash donations in envelopes with their names. This allows people to keep records of what they have received, so that in the future they can pay back whatever they have received in the past. If people attending funerals and weddings were expected to leave donations without identifying who gave how much, this would create a "public goods" dilemma, in which people would be tempted to give less than what was fair.


Even if we have no history of direct reciprocal exchanges with someone, we can judge that person as a trustworthy cooperator if he has a good reputation from exchanges with others, or we can avoid any engagement with him if he has a bad reputation. This is what Richard Alexander called "indirect reciprocity."

Darwin recognized this by stressing the importance of praise and blame in sustaining the social virtues. But Darwin also recognized that indirect reciprocity works only if there's a high probability of the helper accurately knowing the reputation of the person to be helped. He saw that cultural capacities--especially language--improve the reputational information necessary for indirect reciprocity.

The Henrichs accept this, even as they stress that indirect reciprocity does not work well in large groups where it is hard to accurately identify people as having good or bad reputations. They point out that it works well for the Chaldeans only because they have such tight-knit and stable social networks that gossip functions well in providing reputational information about who is trustworthy and who is not.


Darwin saw that one motivation for obeying social norms was the sense of shame based on the fear of social disapproval. As naturally social animals, we are acutely sensitive to the opinions of others in our group. "Even when an action is opposed to no special instinct, merely to know that our friends and equals despise us for it is enough to cause great misery. Who can doubt that the refusal to fight a duel through fear has caused many men an agony of shame? Many a Hindoo, it is said, has been stirred to the bottom of his soul by having partaken of unclean food" (138). As these examples indicate, even seemingly arbitrary norms--like food taboos--that might be maladaptive can be enforced by the fear of social blame.

The Henrichs show how the fear of getting a bad reputation works not only in indirect reciprocity for cooperative norms, but for any social norms enforced by third-party punishment. The importance of third-party punishment--also called "altruistic punishment"--has been seen in experiments with "public goods" games. In such a game, all members of a group benefit from a public good, even those who pay none of the costs in providing the good. In such a situation, it's hard to see how people would cooperate to provide such a good, given the temptation to become free riders. The answer is that cooperation evolves if free riders are punished, and members of the group are willing to incur some costs in punishing free riders. People are willing to inflict such costly punishment because they are moved by moral emotions of anger and indignation. Such third-party punishment can even enforce social norms that have nothing to do with reciprocal cooperation--norms such as food taboos, appropriate clothing, and the choice of a marriage partner.

An example of this among the Chaldeans is the norm of endogamous marriage: Chaldeans should marry other Chaldeans. Unlike gift-giving at a wedding, this norm of endogamous marriage is not a matter of reciprocal cooperation, but it's a social expectation enforced by the willingness of many members of the group to express their moral disgust with those who violate the norm.

Lots of apparently arbitrary and even maladaptive behavior can be explained as arising from social norms enforced by third-party punishment. I have written some posts on female circumcision as an example of maladaptive behavior. The Henrichs see this as a case of a culturally evolved social norm supported by social punishment of those who violate the norm. As we saw in those earlier posts, the abolition of female circumcision requires that a sufficient number of people in a community must band together in agreeing to abolish the practice. Such a strategy can work with female circumcision in Africa, just as it did with female foot-binding in China.


Darwin saw that one crucial element in the evolution of morality and cooperation was cultural group selection through tribal competition. He wrote:

"It must not be forgotten that although a high standard of morality gives but a slight or no advantage to each individual man and his children over the other men of the same tribe, yet that an increase in the number of well-endowed men and an advancement in the standard of morality will certainly give an immense advantage to one tribe over another. A tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection. At all times throughout the world tribes have supplanted other tribes; and as morality is one important element in their success, the standard of morality and the number of well-endowed men will thus everywhere tend to rise and increase" (157-58).

The Henrichs suggest that cultural group selection would have worked through competition in warfare, economic production, and demographic reproduction. Those groups stronger in military, economic, or reproductive advantages would tend to prevail over other groups. And thus those norms that enhanced military, economic, or reproductive advantages would be favored. For example, some historians of early Christianity have argued that the surprising triumph of the early Christians in ancient Rome came from social norms favoring marital fidelity, high reproductive rates, and mutual aid among the Christians, in contrast to the pagan Romans.

A consequence of such cultural group selection is to foster "ethnic markers" as a guide to cooperation. Interactions are smoother when the people interacting are playing by the same rules, because they share the same social norms. Consequently, we are more cooperative with people we can identify as members of our own group. We look for cues to group membership such as language, clothing, greetings, mannerisms, and religious beliefs.

Chaldeans look for those ethnic markers that identify people as Chaldeans--belonging to the Chaldean Church, speaking the Chaldean language, and having Chaldean ancestors from Iraq. These are all ethnic markers that suggest people who share the underlying norms of the Chaldean community.


I am reminded here of some previous posts on evolutionary explanations of the Industrial Revolution as a product of cultural group selection in which certain norms of economic productivity and entrepreneurship favored the the rise of modern commercial societies.

I am also reminded of my post last November on "rights from wrongs," because we might understand the modern liberal idea of natural rights as a product of cultural evolution: we have learned from our historical experience with great injustice that we need the social norm of government securing individual rights as an expression of our moral sense.

I am also reminded of previous posts on Aristotelian liberalism. Groups like the Chaldeans show us how morality and cooperation can be enforced voluntarily in civil society through a pluralism of social groups rather than coercively through the bureaucratic state. The Chaldeans have immigrated to the United States because they want the economic, religious, and political freedom of a liberal society. In such a society, the state does not enforce any one comprehensive conception of the good. Rather, the state enforces a procedural conception of the common good as securing individual liberty, while leaving individuals free to form social groups organized around specific conceptions of virtue.

Friedrich Hayek made this point when he argued that the enforcement of social norms of morality through social pressure (rather than state coercion) was a condition for a free society. Precisely because human beings have evolved to be social animals with a moral sense, they will naturally form social groups defined by moral norms of cooperation within the groups. The role of government, then, is to secure the general conditions that make it possible for individuals to freely form such groups. See, for example, The Constitution of Liberty, 62-63, 145-47, 402, 451; and Law, Legislation, and Liberty, vol. 3, 167-68, 170-71.

Although I have pointed out (in some previous posts) some serious flaws in Hayek's account of cultural evolution, the coevolutionary theory of cooperation surveyed by the Henrichs would support an evolutionary explanation of the emergence of liberalism and the free society as the way of life best adapted for evolved human nature.

A few weeks ago (April 1), I wrote a post on Joe Henrich's recent article in Science on the importance of "market integration" and "world religion" in the evolution of cooperation.

1 comment:

Troy Camplin said...

Some good stuff here. In regards to correcting Hayek, may I recommend my own article FROM THE SENSORY ORDER TO THE MORAL ORDER: BRIDGING
, which I think you might find interesting.