Altruism repays the best-connected individuals

Unselfish behaviour spreads through society in a way that most benefits the "hubs" in the network

Friday, May 29, 2009

How altruistic behaviour emerges has puzzled evolutionary biologists for decades. From the point of view of survivial of the fittest, the unselfish concern for the welfare of others seems inexplicable. Surely any organism should always act selfishly if it were truly intent on saving its own bacon.

One explanation is that altruistic acts, although seemingly unselfish, actually benefit those who perform them but in indirect ways. The idea is that unselfish acts are repeated. So those who have been helped go on to help other individuals, ensuring that this behaviour spreads through a group, a phenomenon known as upstream reciprocity.

Eventually, the individual that triggered the altruistic behaviour will be on the receiving end of least one unselfish act, ensuring that, at the very least, he or she doesn't lose out. In this way, unselfish individuals actually benefit from their altruism.

At least, that's the theory. While other types of altruism have been observed and modelled (for example downstream reciprocity in which people help others who they have seen acting altruistically), upstream reciprocity has proven harder to pin down, until now

Full article here:

http://www.technologyreview.com/blog/arxiv/23584/

In other words, it's easy to act nice when you're already on top.