How would you tell?
I think that's a good question. For one thing, you don't really see people starting businesses aimed at taking advantage of this supposed pay differential. You wouldn't even necessarily need to discriminate to do so, just offer wages low enough that it's primarily women who end up working for you in a traditionally male dominated field.
Where are inexpensive lawn care companies, exterminator companies, auto garages, etc. which make a killing by relying on female labor? You never see them. Even in trades which are more balanced, like law and medicine, you don't see it.
When a belief is floating around, and pretty much nobody is willing to bet their own money on it, it's reasonable to think that the belief falls into the first category, i.e. it's a belief people hold for social/political reasons.
Also, it's pretty obvious just from simple observation that female workers are less willing than men to take on work which is dirty, dangerous, risky or demanding, and more likely to absent themselves from work or even quit over child care issues. In my experience, people who complain about supposed wage gaps generally give short shrift to or even ignore these types of common sense observations. When people ignore common sense and obvious facts that contradict their beliefs, it's reasonable to conclude that those beliefs probably fall into the first category, i.e. those beliefs are held for social/political reasons.
I think that's a good question. For one thing, you don't really see people starting businesses aimed at taking advantage of this supposed pay differential.
In McKinsey you do see a top management consulting companies coaching companies to take advantage of the opportunity.
People can't effectively correct for the hindsight bias if you tell them to correct for it. The same thing is likely true for a lot of people inherent sexism. They might think that they are accurately assessing the skills of woman but are blinded by their own sexism.
...Even in trades
LW readers have unusual views on many subjects. Efficient Market Hypothesis notwithstanding, many of these are probably alien to most people in finance. So it's plausible they might have implications that are not yet fully integrated into current asset prices. And if you rightfully believe something that most people do not believe, you should be able to make money off that.
Here's an example for a different group. Feminists believe that women are paid less than men for no good economic reason. If this is the case, feminists should invest in companies that hire many women, and short those which hire few women, to take advantage of the cheaper labour costs. And I can think of examples for groups like Socialists, Neoreactionaries, etc. - cases where their positive beliefs have strong implications for economic predictions. But I struggle to think of such ones for LessWrong, which is why I am asking you. Can you think of any unusual LW-type beliefs that have strong economic implications (say over the next 1-3 years)?
Wei Dai has previously commented on a similar phenomena, but I'm interested in a wider class of phenomena.