The flap over debate audience reactions raises questions about who picks them, who is really in control of them and whether they can affect voters' choices at the polls. Here, people sit in the audience as they listen to a televised debate in 2008 in Boca Raton, Fla. - 

Jeremy Hobson:In Jacksonville, Fla. tonight, the four remaining Republican candidates for President will debate each other yet again. But unlike the last debate on Monday night, the audience will be allowed to cheer and jeer the candidates as much as they want. The audience has become a key player in the debates this year.

Marketplace's Nancy Marshall-Genzer reports now on how exactly the audience members are chosen.

Nancy Marshall-Genzer: Debate audiences are picked by the sponsor. The Florida Republican Party is the main sponsor of tonight’s faceoff.

Florida GOP spokesman Brian Hughes says seats will go to rank-and-file members.  And they can hoot and holler all they want.

Brian Hughes: Some of the energy that an audience filled with grassroots people can bring – we see that as part of the energy of the debate itself.

That energy exploded in a debate last week when Newt Gingrich attacked the media.

Newt Gingrich: I am tired of the elite media protecting Barack Obama by attacking Republicans.

Paul Light teaches political science at New York University. He says wild applause can influence a debate’s TV audience.

Paul Light: And you kind of forget what the candidate just said and you say 'Wow! These people love him. Therefore I should love him.'

CNN is moderating tonight. If things get rowdy, it says, it’ll “ask the audience to refrain.”

In Washington, I’m Nancy Marshall-Genzer for Marketplace.