Peter Dizikes in the Boston Globe:
It is a puzzle of evolution: If natural selection dictates that the fittest survive, why do we see altruism in nature? Why do worker bees or ants, for instance, refrain from competing with those around them, but instead search for food or build nests on behalf of their companions? Why do they sacrifice their own reproductive success for the good of the group?
In the 1960s, British biologist William Hamilton offered an explanation in a theory now called kin selection. When animals, often insects, help siblings or other relatives survive, they are enhancing the odds that their shared family genes will be passed on. In other words, the genes, not the individual or social group, are what counts in evolution.
Hamilton’s idea was eventually accepted by most biologists, and found an enthusiastic backer, at the time, in Edward O. Wilson, the renowned Harvard evolutionist.
That was then. Now, Wilson has changed his mind, startling colleagues by arguing that kin selection does not lead to altruism.
More here.