Does anyone understand enough to tell us what the "math" is all about? According to the article, the math is key to this ... yet they don't give any info at all about what that math says and how it is relevant. If anyone can enlighten us, please do!
It's up behind a paywall (probably... with my university connection I'm never sure what has it and what doesn't) here: http://www.nature.com/nature/journal/v466/n7310/full/nature0... . If anybody is more mathematically sophisticated than I, wants to tackle it, but can't get through the paywall, send me an email (in my profile).
Skimming through the supplemental information, it seems like they assume a Markov process where individuals adopt one of two strategies (with a preference towards adopting the strategy that their parent adopted), then look at which one is more likely to be dominant in the population.
The math is about the relative costs and benefits of altruistic behaviors. Altruistic behaviors must be a net benefit to an individual or group in terms of reproductive success, or else it would die out of a population. For a business analogy, the behavior needs to turn a profit.
In the case of kin selection in particular, the math is described by Hamilton's Rule, an inequality that must be satisfied in order for kin selection to explain a given altruistic interaction between individuals (http://en.wikipedia.org/wiki/W._D._Hamilton#Hamilton.27s_rul...).
