From Tom Rees of Epiphenom:

There’s a wonderful paper just out in Science that sheds new light on a mystery of human behavior: why people sometimes do good deeds even when they gain nothing from it.
Some forms of altruism can be easily explained by evolution, but evolution can’t explain why people are sometimes generous to completely anonymous strangers. This new study may have found a solution: It isn’t something inherent to our nature, but rather something that we learn to do.
You have seen something of it already, and I’m not going to go into detail on the headline results because you can find them elsewhere. What interests me most about this study is the link they found to religion. But first, here’s a quick overview of what they did and the major finding.
The heart of the study was a standard battery of economic games designed to test the subjects’ understanding of fairness:

* In the Dictator Game, player 1 is given a fixed pool of money (equal to one day’s wages) and can share as much (or as little) as she likes with player 2.

* In the Ultimatum Game, player 2 is given the chance to reject offers that she feels are insultingly small.

* In the Third Party Punishment Game, a third player is given some money as well, and she can spend some of it to punish player 1 if she thinks that the offer to player 2 is too small.

Now, the logical thing to do in all these games is to hold on to all your money. You have nothing to gain by sharing (the games are anonymous), and all that happens is that you go home with less. However, what usually happens is that people do share some money (usually not 50 percent, however!).
What makes the new study unique is that the researchers put together data from the world over, including the rather marvelous Hadza (you can see the locations on the map below; click on image for larger view). Then, they compared how much people contributed with what kind of society they lived in.

They found that contributions were smallest in societies that did not have a market economy (e.g., hunter gatherers). And they found that punishment was lowest in societies formed of small groups.
This potentially resolves the conundrum!
What it suggests is that anonymous altruism is not part of our evolutionary makeup, but instead is something that we learn from the society around us. The reason big, complex societies can exist is that we drum it into our kids that they must be fair and kind to strangers (against their natural instincts).
So what’s the connection with religion?
Well, the researchers also showed that, in two out of the three games, the anonymous contributions were higher in those groups that had converted from tribal religions (in which gods do not enforce morality) to a “world religion” (in practice, either Christianity or Islam).
On the face of it, this supports the idea that “world religion” is a cultural adaptation to allow the formation of complex societies. The invention of an all-seeing, morally concerned god increases the honesty in anonymous transactions, and thus allows large, integrated communities to develop. When you look at the history of religions, it’s clear that the development of religious ideas has progressed in tandem with the increasing complexity of society. Robert Wright has written a book on the topic, and in the study’s supplementary material, the authors give a nice summary of these ideas.
It all sounds very plausible. However, it’s not quite that simple, for a whole host of reasons.
First is the problem that a “world religion” may be a cause, not a consequence, of a complex society. A world religion is essentially one that’s popular over a large geographic area. However, the exchange of ideas that always goes together with the exchange of goods will inevitably bring about a convergence of beliefs to create a “world religion.” So, you would expect a complex, diverse society to develop some kind of syncretic belief system. And that belief system would inevitably encapsulate the social norms of the complex society that created it. People create a god in their image.
Suppose, for example, that countries with more parasites end up with more fractured societies that are naturally less trusting of strangers. After all, strangers could bring with them disease. Studies have found that this is exactly the pattern you see: People living in high-parasite regions are less open to strangers and have more fractured religions. These societies, with their tribal rather than world religions, would naturally be less cooperative in anonymous games.
Perhaps moralizing gods are not required for complex societies. After all, the Romans and Greeks created large, complex societies despite having a pantheon of gods who were not exactly paragons of virtue. And the reality is that, in modern societies at least, nonbelief is correlated with less corruption and more trust. Social norms, rather than god beliefs, seem to be of primary importance.
As support for the hypothesis that “world religions” promote prosocial behavior, the authors quote a small study that found, in a similar economic game, that subliminal religious primes (i.e., a quick flash of a religious word) were marginally more effective in believers than nonbelievers. However, they also showed that nonreligious primes were equally effective, and that without the priming, both religious and nonreligious people were equally prosocial. What’s more, other studies, including this one, have shown that the prosocial effects of religion are all about the situation rather than the beliefs.
Put these findings together and what you get is the strong suggestion that the way to encourage prosocial behavior is to remind people about their cultural training (religious or otherwise). The more you reinforce a social norm of cooperation, the more people will cooperate.
Now, that doesn’t rule out a role of religion in stabilizing societies. In fact, I’m inclined to think that there must be a link. But it is fearsomely difficult to prove, and it’s clear that whatever the link is, it’s much more complicated than it appears at first sight.
I’m going to leave you with one other niggling anomaly from the paper. Remember that “world religion” was associated with more prosocial behavior in only two out of the three games. Maybe you were wondering which was the one out?
Well, the game was the Third Party Punishment Game. This is the game in which player 1 should give more money if they fear that player 3 might spend some cash to punish offers that were too low. It’s a particularly relevant test because third party intervention to enforce the rules is a crucial feature of complex society.
Unlike the other two games, being Christian or Muslim had no effect on player 1’s offers. What makes this doubly fascinating is that this is the only game in which wealth and income affected player 1’s decisions. The authors suspect it might be that the introduction of a “judge” reduces the intrinsic motivation. In other words, the offers players make depends on what they think the judge will approve of rather than what they themselves think is fair.
However, I couldn’t help but be reminded of another study that looked at punishment behavior in a similar game. It examined a cross-section of relatively high-income countries and found high levels of cooperative punishment and low levels of anti-social punishment in the least religious societies.
Conceivably, if you don’t believe that there is a god on hand to enforce the rules, you might just be motivated to do it yourself!