Almost everyone takes this for granted, but it still freaks me out: Audiences in presidential debates applaud just because a candidate says something they agree with. See for example the crowd’s reaction when Giuliani scoffs at Ron Paul.

You can say “it’s only human” to clap for our spokesmen, but consider the consequences. Audiences are giving speakers powerful psychological incentives to conceal any information that challenges their beliefs. Why not just hold up big signs that say: “TELL US WHAT WE WANT TO HEAR”?

Keep this in mind the next time someone blames politicians for the low quality of political dialogue. The hard truth is that politicians are just responding to the perverse incentives that the people give them. Voters do not hold foolish views because their politicians mislead them. Politicians mislead voters because voters have foolish views – and respond poorly to criticism.