Razib discusses the paper by Traulsen and Nowak about how group selection can occur.
I've covered this topic in several other posts, most notably here and here regardng a paper by Sam Bowles in Science where he shows that multilevel selection could occur in humans due to high relatedness within groups, high levels of inter-group conflict, and reproductive leveling. He notes that it is hard to distinguish group selection from kin selection.
Now comes this new paper in PNAS (see below) that argues that group selection is synonymous with kin selection. I think this probably applies to humans as we tend to extend kinship terms and emotions to everyone in the group, thus facilitating very extended kin selection that would be otherwise limited within other primate groups.
I did not get into the mathematical modeling of this paper. I'd be interested to hear what Razib has to say about it.
Group selection and kin selection: Two concepts but one process
Laurent Lehmann, Laurent Keller, Stuart West, and Denis Roze
PNAS Published online before print April 6, 2007
Absract: In a recent paper, Traulsen and Nowak use a multilevel selection model to show that cooperation can be favored by group selection in finite populations [Traulsen A, Nowak M (2006) Proc Natl Acad Sci USA 103:10952-10955]. The authors challenge the view that kin selection may be an appropriate interpretation of their results and state that group selection is a distinctive process "that permeates evolutionary processes from the emergence of the first cells to eusociality and the economics of nations." In this paper, we start by addressing Traulsen and Nowak's challenge and demonstrate that all their results can be obtained by an application of kin selection theory. We then extend Traulsen and Nowak's model to life history conditions that have been previously studied. This allows us to highlight the differences and similarities between Traulsen and Nowak's model and typical kin selection models and also to broaden the scope of their results. Our retrospective analyses of Traulsen and Nowak's model illustrate that it is possible to convert group selection models to kin selection models without disturbing the mathematics describing the net effect of selection on cooperation.