General presidential debates, the face-off between the top candidate from both parties, get people excited about politics. The epic clash of worldviews on a high-stakes, high-pressure stage gets the nation to tune in and root for their party's superstar. But in spite of all the hype and attention, the general debates don't really matter — very few voters change their minds after watching. Primary debates, on the other hand, matter a lot in who will rise and fall in the race for the White House. Watch why:

A study of several years of presidential debates found that 86.3 percent of participants showed no change in voting intention after watching general debates.

The same study showed a much larger effect from primary debates. Only 40 percent of participants stuck with their original voting intention after watching the primary debates. The other 60 percent either changed candidate preference or became undecided.

This makes sense. In the primaries, everyone is on the same team, in a sense. Voters all have the same goal: to get a representative from their party into the White House. This means that performance matters more than in the generals, where party loyalty usually determines voting intention.

Primary voters want to pick someone who will perform well for their party on the national stage come general season. The primary debates become a crucial proving ground for candidates trying to win the trust of their party: Scrutiny is high and opinions are fluid, making a small gaffe a big deal for debaters. This makes for a more consequential debate.

To see examples of what this looks like, see the above video.