May 09, 2011

Is Kin Selection Dead and Is It Time to Move On in Understanding the Evolution of Cooperation?

Peter Nonacs, UCLA Department of Ecology and Evolutionary Biology

Hamilton’s theory of inclusive fitness broadly states that whether or not a trait increases in frequency is dependent on both the direct reproductive success of individuals having that trait and the help that such individuals can provide to other trait bearers for their reproduction. The latter portion of inclusive fitness is commonly known as kin selection and has become the dominant paradigm for the evolution of cooperation: I.e., helping genetic relatives reproduce can create a net increase in inclusive fitness even with a substantial loss in direct reproduction. Recently, however, Martin Nowak has argued that the mathematical foundations of inclusive fitness theory are inappropriate for predicting the evolution of cooperation (1). Edward O. Wilson has gone even further and claimed that, “Kin selection is wrong” and a “gimmick” (2). Instead, Wilson proposes cooperation evolves through group selection. Not surprisingly, their claims have drawn considerable criticism (3), with Richard Dawkins going so far as to pronounce that he has “never met anybody apart from Wilson and Nowak who takes it seriously (2).” I will look at both sides of this issue and attempt to separate the scientific concerns from the heated clashes of personalities. At issue appears to be the question of the evolutionary advantages of genetic diversity versus kinship. Both can be advantageous, but they are simultaneously incompatible. Their resolution requires a multi-level approach as nepotism favoring kin can be selected for within groups, but genetic diversity is selected for only across groups.

(1) Nowak et al. 2010. Nature 466: 1057-1062.


(3) Abbot et al. 2011. Nature 471: E1-E4.