On Tuesday, the presidential election finally takes place. When it comes to what led to the outcome, a case can be made that political pundits on the left and right have got it all wrong. That’s because their expertise makes them uniquely unqualified to understand disengaged voters. Political pundits are like sportswriters trying to fathom why some people pay no attention to the Super Bowl. Yet disengaged voters will likely determine the winner. Why? Because these are the only voters still up for grabs.

Engaged voters have already decided who they’ll vote for. Some decided based on ideology (liberal or conservative). Others decided based on group interest (labor status, ethnicity, gender, religion). Some decided based on how they answered the question: Are you better or worse off than you were four years ago?

So who are the disengaged? These are undecided potential voters who just don’t care about politics. As a result, they process information about campaigns in ways that are unfathomable to those fully engaged.

In July, YouGov reported crunched polling numbers from a survey to identify characteristics of “disengaged” voters. The disengaged consume little political news; they are largely ignorant of political issues. They are less likely than others to actually vote. They tend to be “on average younger, more likely to be women, more likely to be Black or Hispanic, less educated, and have a lower household income than the average engaged American voter.”

Scientific models suggest that people take in information and make decisions using different mental processes. To varying degrees, engaged voters process information systematically. They connect issues together through mental links. Because of these intricate connections, the engaged decide early and are unlikely to change their minds. Changing their minds on one issue means changing their minds on others.

The disengaged take a different approach. They do what scientists call “heuristic” processing. They rely on peripheral cues that have very little to do with issues and candidate qualifications. For example, physical appearance of candidates can sway the disengaged. Research shows that people tend to like others who are physically attractive. If one doesn’t care much about politics, then appearance could serve as a basis for choosing. Using stereotypic notions of “good looks,” John F. Kennedy was better looking than Richard Nixon. Kamala Harris is better looking than Donald Trump.

Research dating from the 1940s shows that many disengaged voters depend on more engaged voters for advice (two-step flow). They also tend to take advice from people they admire, regardless of political expertise.

Arguably, this is why Taylor Swift’s endorsement of Harris could prove so impactful. After the Sept. 10 debate, the singer posted her endorsement on Instagram. According to Axios, Swift has 283 million Instagram followers. The Instagram post inspired 338,000 Swifties to visit Vote.gov, the federal voter registration website, during the 15 hours after her post.

One can only speculate how many Swifties are young women that YouGov identified as politically disengaged. Whether Swifties actually registered and will vote is also subject to speculation. Historically, celebrity endorsements don’t seem to improve a candidate’s chances. Ask Hillary Clinton. Normally, debates don’t have much impact either. But this is no normal campaign. Ask Joe Biden. In a close race, a percentage point boost from the disengaged in swing states could decide the election outcome.

Dozier, Ph.D., is professor emeritus in the School of Journalism and Media Studies at San Diego State University. He lives in Encinitas.