Evidence That Generosity Is Contagious

Here’s a neat illustration from James Fowler of the University of California, San Diego and Dr. Nicholas Christakis of Harvard University that shows how kindness and generosity can spread from person to person to person, even when they’re strangers, creating what amounts to a domino effect.
Experiments found that if Eleni increases how much money she contributes to the public good when paired with Lucas, it benefits Lucas, and he gives more when paired with Erika. Erika then gives more when paired with Jay, and he gives more when paired with Brecken. The effect seems to last through three degrees of separation, meaning Eleni’s initial contribution can be tripled.
The kindness and generosity also spreads over time: Lucas gives more when paired with Erika and also when he’s later paired with Lysander, Bemy, Sebastian, and Nicholas. The results suggest that a small number of people can make a huge positive difference.
“Personally,” Fowler says in a write-up of the research, “it’s very exciting to learn that kindness spreads to people I don’t know or have never met. We have direct experience of giving and seeing people’s immediate reactions, but we don’t typically see how our generosity cascades through the social network to affect the lives of dozens or maybe hundreds of other people.”
It’s important to keep in mind that if Eleni decreases her contribution to the public good, that uncooperative behavior can spread through the social network as well, the researchers say. But as Christakis (who also co-wrote the book Connected with Fowler) points out:

Our work over the past few years, examining the function of human social networks and their genetic origins, has led us to conclude that there is a deep and fundamental connection between social networks and goodness. The flow of good and desirable properties like ideas, love, and kindness is required for human social networks to endure, and, in turn, networks are required for such properties to spread. Humans form social networks because the benefits of a connected life outweigh the costs.

Help Haiti by Buying Positive Psychology Books

Robert Biswas-Diener is donating proceeds of the sales of his workbooks to the Mercy Corps relief mission.

Positive Interactions Promote Cooperation

stick+and+carrotMartin Nowak is quite excited about his new paper in this week’s Science. He writes to us:

I think it has a simple and very interesting result: Reward is better than punishment in promoting public cooperation. (Surprisingly, this finding goes against the current dogma in the field.)

In this case, Nowak and his team had groups of volunteers play a public goods game in which players could decide how much money they wanted to contribute to a common pot and how much they wanted to keep for themselves (the pot would then be divided evenly among the players). Obviously, it’s best for the group if everyone donates the maximum, since it means more money for everyone, but self-interest tells us to donate nothing and freeload off the group. So the researchers added a catch to the classic problem: In some games, players could reward or punish another player for his contribution or lack thereof.
After many rounds of the game, it turns out reward and punishment are equally good at promoting cooperation within the group. But groups in which people could reward each other ended up wealthier than the groups in which people used punishment. When both options are available, rewarding other players leads to greater contributions and payoff, while punishment has no effect on contributions and leads to lower payoff.
As the researchers then note in their paper:

Sometimes it is argued that it is easier to punish people than to reward them. We think this is not the case. Life is full of opportunities for mutually beneficial trade, as well as situations where we can help others, be they friends, neighbors, office mates, or strangers. We regularly spend time and effort, as well as money, to assist people around us. This assistance can be minor, like helping a friend to move furniture, working extra shifts to cover for an ill co-worker, or giving directions to a tourist. It can also be more important, like recommending a colleague for promotion or speaking out to support a victim of discrimination. These sorts of productive interactions are the building blocks of our society and should not be disregarded.

Why Friendship Is Like Alliance Politics

If you’ve ever watched the TV show Survivor, you’ve no doubt noticed how crucial alliances are and how they constantly change and shift as players jockey for position and try to keep themselves from getting voted out of the game. Part of the reason an alliance of more than two people is so hard to keep together is that there’s always a hierarchy of allegiance; loyalty, support, and protection do not apply equally among all. This is usually the argument one alliance uses to lure over a player from the bottom of another, bigger alliance: Being fourth from the top in our alliance, they say, is better than being fifth from the top in theirs. It’s an argument that works with varying success.
So I was interested to read about a new theory called the “Alliance Hypothesis for Human Friendship,” based on a study by Peter DeScioli and Robert Kurzban, psychologists at the University of Pennsylvania. The psychologists say that how you rank your best friends is closely related to how you think these friends rank you.
As Kurzban notes:

Friendships are about alliances. We live in a world where conflict can arise and allies must be in position beforehand. This new hypothesis takes into account how we value those alliances. In a way, one of the main predictors of friendship is the value of the alliance. The value of an ally, or friend, drops with every additional alliance they must make, so the best alliance is one in which your ally ranks you above everyone else as well.

Traditionally, friends have been thought of as “exchange partners” based on the “theory of reciprocal altruism.” But research has shown that we don’t regularly keep track of the benefits we give and receive in our close friendships, and we help close friends even when the likelihood of them repaying us is slim. The “alliance” theory of friendship is more optimistic since “it’s not what you can do for me, it’s how much you like me,” says Kurzban. “In this manner even the weakest nations, for example, or the least popular kid at the party with nary an alliance in the room is set up to be paired with someone looking for a friend.”
Assuming he’s right, can we use this to our advantage? Yup, the psychologists say, by 1) ranking our friends, 2) ranking them according to our position in their rankings (preferring friends who rank us higher—our more reliable allies), and 3) hiding our friend-ranking. —Heather Wax