Voters aren't selfish. That's an important question where the political scientists are right and the economists are wrong. But I part company with the political scientists when they draw implications about how well democracy works. After they shoot down the Self-Interested Voter Hypothesis (SIVH), lots of political scientists can't resist the following leap:
Economists argue that voter selfishness makes democracy work badly. Fortunately, however, voters aren't selfish, so most of the "democratic failures" that economists fret over are just in their heads.
This would be true if voters actually understood policy. Selfish voters would choose the policies best for themselves; unselfish voters would choose the policies best for society. Then, unselfishness gets you a better overall result.
But what happens if people have systematically biased beliefs about policy - for example, if they underestimate the social benefits of the market mechanism? How does bad cognition interact with voter motivation?
This is the question I ask in one of my favorite papers. (Aside: Tyler Cowen said it was unpublishable. I told him he was wrong after Social Science Quarterly took it, but he replied that I was being "too essentialist"!) The gist of my answer is that if voters have systematic biases, unselfishness is worse for society than selfishness.
Why? If selfish voters misinterpret markets as a method for the rich to exploit the poor, at least the rich will still favor markets. They'll want what they falsely see as their "pound of flesh." But if unselfish voters misinterpret markets as a method for the rich to exploit the poor, the rich and poor alike will unite against the imaginary evils of the market. Instead of petty squabbling, we get a consensus for folly.
If you find it hard to believe that unselfish motivation ever makes the world worse, think about a mad scientist. He imagines he's got the cure for what ails you, but all he's got is a syringe full of cyanide. If the mad scientist were selfish, he'd demand payment for his "treatment," and you'd be safe. "Thanks, but no thanks!" The real danger is the unselfish mad scientist. He'd insist on helping you whether or not you paid. Indeed, he'd probably help you even if you screamed "No!" "You'll thank me once you're cured," he'd insist.