Applaud Info, Not Agreement
Bryan Caplan makes the point:
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. … 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"?
Yup.
Andrew, I believe that there are risks involved in saying just what others want to hear when that deviates from the truth, perhaps most importantly because if the others find you out you get punished for the lie. And since small lies are more easily concealed, it's a stable strategy to just say what others want to hear part of the time.
Dave, it is not so much the name, as that participants offer arguments instead of just making claims. More generally, we rarely see any speakers vigorously applauded for providing new info.
Andrew, often we express dominance by disagreeing, and submission by agreeing, and so we disagree to try to signal dominance.