When 20 of the Democratic candidates for president take the stage this summer during a series of primary debates, what should voters be paying attention to? In general, presidential debates, both in the primary and general election, get a lot of hype from the pundits and networks, but ultimately, how much do they matter? Salon's Amanda Marcotte spoke to Kenneth Mayer, a political science professor from the University of Wisconsin-Madison, to find out.

For voters looking forward to the Democratic debates, Mayer has some good news: When it comes to primaries, debates can matter, because the politicians are speaking to audiences who haven't yet made up their minds on how to think about things.

Mayer gives plenty of sensible guidance that's needed in our times of high political drama, explaining how much we can tell from polls this far away from the election (not much) and what we should expect to see as the thick Democratic field of presidential candidates compete with each other (total chaos).

The media may be treating this primary like it's as good as over, but in truth, a lot can happen, especially with this unprecedented number of candidates. Watch the video above to hear Mayer's helpful advice for voters trying to figure out how to get the most out of watching the debates and strategies to use for those who want to keep an open mind.