The males of our closest relative, the chimp, have sexual preferences almost completely opposite to us. They prefer the older females towards the end of their breeding lives. The reason for the difference seems to be that male chimps are highly promiscuous, pursue only short term “pump and dump” relations with the females and don’t play any role in the raising of their offspring so it makes sense for them to go for the older females of proven fertility and mothering ability.

Human males seem to be wired to choose females more for long term than short term relations. They prefer young females nearer the beginning of their breeding lives that have the maximum long term breeding potential.

So the big question is why has this system evolved in us but not chimps?

The authors don’t say that they explained the behavior, no; what they do say is that they show ideas like the grandmother hypothesis aren’t necessarily required. Which is true, of course, but we didn’t need the model to tell us that; it doesn’t get us anywhere new. The authors could have written “if men preferred younger mates, women could potentially accumulate mutations resulting in menopause as a byproduct” and left it at that without the quality of the paper suffering much.

I have the same concern with using mathematical models that I tend to also have with using brain scans to do psychology: as tools, they aren’t doing much (or sometimes any) of the theoretical lifting that research requires, but some people have the impression that they do. I hope to do whatever small part I can to convince people of that. Mathematically one one can demonstrate that anything is plausible, given the right set of assumptions. Mathematical plausibility is distinct from biological plausibility though, as Cohen eloquently stated in his commentary on the piece. I’m all for building on ideas, but that is precisely what this paper fails to do.

I understand your skepticism, however tagging some topics as game theory can be tricky. There’s something called “expected value”, which is basically the way most games are evaluated either as a win or a loss. I think it’s important to separate the quantitative from the qualitative when dealing with human situations. A model is never perfectly quantitative (as the study in question portrays) nor it is perfectly qualitative as most evolutionary psychologists would explain the world. It’s probably (as in probability) somewhere in between. This becomes even murkier when you take processes into consideration, but that’s a different discussion altogether.

So yes, the study is too simplistic, but as an effort, it has some validity. Mathematical models usually start that way… The idea is to present an idea that can help someone to come up with a better model. I compare this to the initial efforts in trying to explain traffic jams, which now have developed to travel kits, when it comes to explaining traveling behaviour. This building-block approach is not always present outside the “exact” sciences, which is a real shame, but I understand the difficulties for this to happen: explaining gravity is peanuts compared to explaining human behaviour.

So again, credit where it’s due… I don’t think the authors of the study pretended to explain human behaviour as such… Give a hint maybe, but not a full-fledge explanation. They simply wanted to offer a point of entry for further discussion, and this is how it should be understood. Your points are quite valid nevertheless… What lacks possibly is a more constructive or collaborative approach.