As the Economist explains:
The two researchers came to this conclusion after looking at 486 Americans, 223 Argentinians and 793 Danes. They collected data on their volunteers’ strength by measuring the circumference of the flexed biceps of an individual’s dominant arm. (Previous work has shown that this is an accurate proxy for strength.) They then measured people’s status with questionnaires about their economic situation. And they determined a person’s support for redistribution by asking the degree to which he or she agreed with statements like: “The wealthy should give more money to those who are worse off”; and “It is not fair that people have to pay taxes to fund welfare programmes.” They also asked about participants’ political ideologies.
Dr Petersen and Dr Sznycer found that, regardless of country of origin or apparent ideology, strong men argued for their self interest: the poor for redistribution, the rich against it. No surprises there. Weaklings, however, were far less inclined to make the case that self-interest suggested they would. Among women, by contrast, strength had no correlation with opinion. Rich women wanted to stay rich; poor women to become so.
This is an example of a depressingly common feature: not only are we not terribly rational about our politics but we’re also unaware of our own irrationality. I mean when did you last hear someone explain their views on the welfare state with reference to their biceps?