In 2011, Stephen Colbert came to D.C. to talk about campaign finance. He stood outside the Federal Election Commission, surrounded by about 200 people and told a knock knock joke.

“Knock knock,” Colbert said. “Who’s there?” responded the crowd. “Unlimited union and corporate campaign contributions.” “Unlimited union and corporate campaign contributions who?” “That’s the thing,” Colbert said. “I don’t think I should have to tell you.”

Apparently, people who ate up this method of explaining outside money were far more knowledgeable about America's changing campaign finance law than those who didn't. This news comes from a new study published by the Annenberg Public Policy Center at the University of Pennsylvania titled, "Stephen Colbert's Civics Lesson: How Colbert Super PAC Taught Viewers About Campaign Finance."

As David Carr reported in 2011,

“I am much taken by this and can’t think of any real parallel in history,” said Stephen Hess of the Brookings Institution. “Yes, comedians have always told jokes about elections, but this is quite different. This is a funny person being very serious, actually talking about process. What comedian talks about process?”

Bruce W. Hardy, Jeffrey A. Gottfried, Kenneth M. Winneg and Kathleen Hall Jamieson found that watching the Colbert Report made viewers think they knew a lot about super PACs. Watching Fox News, listening to talk radio and reading newspapers had a similar effect on Americans' rating of their understanding of super PACs. If you watch the nightly network news, you were more likely to say you didn't know as much about super PACs. The researchers controlled variables like political knowledge and political behavior -- the results don't show that Colbert viewers are smarter or more politically engaged, but that all viewers were learning new things about campaign finance.

When it comes to 501(c)4s -- political nonprofits that don't need to disclose donors -- MSNBC viewers, newspaper readers and talk radio listeners were more likely to self-report knowledge about the issue.

When it comes to actual knowledge about super PACs and 501(c)4s, however, watching "The Colbert Report" had a more significant effect than all other forms of news consumption. This effect was unique to campaign finance -- watching "The Colbert Report" did not seem to make viewers much smarter about politics writ large, just with money in politics.

Bruce Hardy, the study's lead author, says there were "no news sources that were sucking knowledge of super PACs out of people's brain," but they did find that there was no significant connection between watching CNN, MSNBC or Fox News and knowledge about super PACs

We've had suspicions about this before. In 2012, the Fix wrote about how mentions of super PACs spiked on the Internet every time Colbert covered the subject on his show.

Not only has this study found that Colbert helped the public understand tangly campaign finance laws; previous research has shown that watching "The Colbert Report" can be a "'‘gateway’ to additional news use."

Hardy says that there are lessons here for the mainstream media to pick up. "One of the questions I've been getting asked is whether mainstream media outlets should try to start their own super PACs too, and obviously we don't want these news outlets to get involved in the political process," he said. "But the use of narrative, telling a story to explain super PACs and making people return each week to find out what happens next, that's maybe something more news outlets should try to emulate.

If you'd like to test the findings of this study, here are some of Colbert's campaign finance greatest hits.

"Let's start with the basics. What's a PAC?"

Can Colbert run for president of the United States of South Carolina and run his super PAC? No. But Jon Stewart can.

What about 501(c)4s? Featuring Ham Rove.

How does one create a super PAC?