The claim (by Michael Peterson, Daniel Sznycer, Aaron Sell, Leda Cosmides, and John Tooby) is pretty grandiose given the data on which it is based. The data are regression coefficients from some surveys, mostly of college students, who answer some questions about income and redistribution and have their biceps circumferences measured. The claim: “physically weak males are more reluctant than physically strong males to assert their self-interest.” To me this seems like a naive view of political attitudes, the idea that a low-SES conservative or a high-SES liberal holds these views because he is “reluctant to assert his self-interest.” Given that they’re surveying college students, I don’t know why they didn’t just directly ask about self-interest, for example views on student loan supports. But I don’t want to get into a series of criticisms here: my problem with the paper isn’t that it’s necessarily wrong but rather that it’s not at all convincing.
As a political scientist, I’m particularly sensitive to these sorts of overstated claims, which I used to associate with economists, but now I seem to be seeing it more and more in psychology journals.