“There was a debate in New Hampshire in which they said be polite, no cheering, no booing, and nobody minded,” said Gwen Ifill, the PBS correspondent and moderator of two vice presidential debates.

In fact, the protocol for the general election debates, which are overseen by the Commission on Presidential Debates, is that audiences sit in virtual silence or risk being escorted out.

But the primary debates play by different rules. They are often co-sponsored by state parties or other political organizations, like the Tea Party Express, which teamed up with CNN for a debate in September. These groups are given discretion over most of the tickets, meaning that the audiences are usually a politically charged bunch.

And this year, the theatrics on the stage have been enlivened further by some colorful players, including Mr. Gingrich, a former Fox News contributor, and Herman Cain, a former pizza company executive and talk show radio host. Both men know how to work an audience. And before they dropped out of the race, Mr. Perry and Representative Michele Bachmann were both practiced enough in the art of the television sound bite that they could occasionally deliver a zinger even if it did not always roll off the tongue.

Network executives from Fox and CNN argue that regardless of the occasionally unruly crowds, their presidential debates are civic exercises intended to help educate and inform voters. But they also see the debates’ value as television productions. Active, engaged crowds are fun to watch. People who sit on their hands are not.

A debate with a mute audience, said Michael Clemente, senior vice president for news at Fox News, “is like a movie without a soundtrack.” Fox’s productions tend to be some of the slickest in the business, complete with a boom camera that sweeps over the roaring crowd, sometimes thousands strong.

Mr. Clemente says he sees civic value in allowing voters to react, something he believes they have come to expect at a time when anyone can pick up a smartphone and become an insta-pundit. “So many people are empowered by Twitter, Facebook. You have people who feel like they’re not just there to listen.”