Cooperative behavior is contagious and it spreads from person to person to person. When people benefit from kindness they "pay it forward" by helping others, say researchers.
In a study published in the March 8 early online edition of the Proceedings of the National Academy of Sciences, researchers from the University of California, San Diego and Harvard have provided the first laboratory evidence that good acts spread just the way bad ones do.
The research was conducted by James Fowler, associate professor at UC San Diego in the Department of Political Science and Calit2's Center for Wireless and Population Health Systems, and Nicholas Christakis of Harvard, who is professor of sociology in the Faculty of Arts and Sciences and professor of medicine and medical sociology at Harvard Medical School.
In the study, Fowler and Christakis show that when one person gives money to help others in a "public-goods game," where people have the opportunity to cooperate with each other, the recipients are more likely to give their own money away to other people in future games. This creates a domino effect in which one person's generosity spreads first to three people and then to the nine people that those three people interact with in the future, and then to still other individuals in subsequent waves of the experiment.
The effect persists, Fowler said: "You don't go back to being your 'old selfish self."" As a result, the money a person gives in the first round of the experiment is ultimately tripled by others who are subsequently (directly or indirectly) influenced to give more. "The network functions like a matching grant," Christakis said.
"Though the multiplier in the real world may be higher or lower than what we've found in the lab," Fowler said, "personally 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."
The study participants were strangers to each other and never played twice with the same person, a study design that eliminates direct reciprocity and reputation management as possible causes.
"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," said Christakis. "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." (ANI)