ABSTRACT
Group selectionist ideas were motivated by the perception of altruistic behavior in the natural world. It is hard to see how altruism could evolve by individual selection, for in mixed populations the selfish do better by free-riding on the others. But it is not hard to see how groups of altruists would out-compete selfish groups. Sadly for these visions of benevolence, group selection fell on very hard times. Lack (1966) argued that reproductive restraint can benefit the individual. More generally, Maynard Smith (1964) and Williams (1966) argued that once made explicit, the assumptions on which group selection relies seem very implausible. In sum, the reactions to group selection took three forms: the first was an alternative conception of evolution and the units of selection, the second was an alternative explanation of altruism and other explanatory targets
of group selection, and the third was a direct critique of group selectionist explanations.
