Economist (and occasional Reason contributor) Bryan Caplan, author of The Myth of the Rational Voter, points out that Romney's 47 percent gaffe is rooted in a misunderstanding of something political science is pretty sure of: most people don't vote based on their own perceived self interest.
As Caplan explains:
Many people believe that voters' positions are determined by their objective self-interest. I call this the SIVH—the Self-Interested Voter Hypothesis. A massive body of evidence shows that the SIVH is just plain wrong. Self-interest has no more than sporadic marginal effects on political views.
Successful politicians usually seem well-aware of the weakness of the SIVH. To win support, they appeal to the public interest and ideology, not self-interest. What's really strange about Romney's recently revealed gaffe, then, is that he seems to take an extreme version of the SIVH for granted. "There are 47% of the people who will vote for the president no matter what." Why? "47% of Americans pay no income tax." The mechanism:
"[T]here are 47% who are with [Obama], who are dependent upon government, who believe that they are victims, who believe the government has a responsibility to care for them, who believe that they are entitled to health care, to food, to housing, to you-name-it. That that's an entitlement. And the government should give it to them. And they will vote for this president no matter what."
Wrong, wrong, wrong. The 47% won't vote for Obama "no matter what." Almost half of voters who earn less than the median income vote Republican in the typical election. A person doesn't support the nanny state because he wants government to take care of him; a person supports the nanny state because he wants government to take care of us. I say this even though I'm far more opposed to the nanny state than Romney has ever been.