It turns out that caucus attendees are different from primary voters, but not because they have a stronger commitment to politics. Rather, caucus-goers are outliers because they tend to be more engaged in community endeavors, like in volunteering and school committee work, compared to primary voters.
Why? His explanation:
The reason for this might be that an intense interest in politics is not the only reason why voters choose to participate in caucuses, whereas it is the predominant rationale for primary voters. Consider the logic. The only reason to participate in a primary is to cast a ballot. But caucuses offer ancillary benefits to participants. Compared to primaries, the public setting of the caucus attracts people who are not foremost concerned with expressing a political opinion, but voters who want to see the spectacle and be seen. The caucus is an event. Moreover, it’s a public event (often accompanied by potluck snacks!). Caucuses, remember, take place mostly in rural states in the dead of winter; they provide a rare opportunity in the calendar for neighbors to gather and reconnect. And there’s also a potential social cost for abstaining – if your neighbor is an activist who asks you to attend, and you’re a no-show, you’ll have to answer for it in the morning.
This helps explain why the likely caucusgoers I’ve talked to don’t seem particularly chagrined by the process.