It’s an unofficial policy in the marriage of my two dear friends that, when Election Day comes, they won’t cancel out each other’s votes. They spent the run-up to a recent local special election locked in an extended game of chicken, privately waiting to see who would cave first and back the other’s candidate, all the while publicly supporting their individual choices. Ultimately they decided they couldn’t countenance a flip-flop, even shielded by the secrecy of the voting booth. As one of them put it, “We held hands as we walked across the street to our polling place, split the progressive vote, and got our stickers.” Both of their candidates lost to the establishment guy.

By the terms of our democracy—one person, one vote—my friends’ efforts to avoid blocking each other aren’t strictly logical. For one thing, why calculate the value of your vote in a closed equation with your partner’s? As we all know, it’s actually part of a much larger numbers game, one that involves the people across the street, across the river, and, depending on the election, across the country. And yet proximity has power. If my partner were to cast a ballot opposite my own, then—at least within the insular world of the household, which is where many of the frankest and most formative political conversations occur—I would also feel that my vote, and my participation in the democratic process, was on some level moot.

Political scientists have studied this feeling, which in some borders on superstition, for years. “Politics are incredibly contagious in social networks,” writes Betsy Sinclair, of Washington University in St. Louis, in her 2012 book, The Social Citizen. Sinclair argues that most people seek out friends and build communities based on characteristics—socioeconomic and demographic factors included—that may correlate with political views but that are not first and foremost political. This leaves the door open for social networks to exert political pressure, directly or indirectly. “Because of the high value individuals place on these social relationships and the difficulty in sustaining relationships when disagreements occur, individual political preferences and behaviors compete with the desire for stable social relationships,” Sinclair writes. “Social influence complicates the democratic process, as an ideal democracy relies on individual political expression and preferences.”

If social conformity works as a magnetic field beneath our politics, then the pull is usually strongest within families. A 2007 study on German and British families found that influence was a two-way street between husbands and wives, and between parents and children. Research on American families has also found that most people list spouses and family members as their most frequent partners in political discussion, and spouses in particular as the most popular targets of efforts to change another person’s political views.

There’s no doubt that the linkages between voting and identity, identity and community, breach the simplicity of “one person, one vote.” For many of us, the fact that we’re alone in the voting booth doesn’t change the feeling that we’re socially accountable for what we do in there. Take my friend, who considered reneging on his candidate to align with his wife, as an example. It didn’t matter if no one ever found out that he’d switched: he’d have known, and the person whose good opinion matters most to him would’ve, too.

For some people, a family member’s intrusion into their voting habits is an unalloyed good. Researchers from Harvard and the University of California, San Diego, tried to quantify the positive effect that marriage—as well as other strong, especially cohabitational, social ties—has on voter turnout by studying widows, widowers, and divorcées. Having a partner to go to the polls with simplifies the logistics of voting and increases motivation. “It might be unusual to invite a friend to go vote with you unless you are both highly political,” the researchers observe, but people who live together encourage and accompany one another even if voting is low on their respective to-do lists. Overall, the researchers estimate that, in any non-presidential election, over a million divorcées and widowed individuals who voted consistently when they were partnered are instead staying home. They also found that people who continue living with other registered voters after the end of a marriage vote at higher rates than people who wind up living alone.

Put simply, people who are socially connected are more likely to participate in politics. Some days it’s friends, family members, spouses, and so on who get us into the booth at all. Is that a fair trade-off for true political autonomy? The image of my friends walking hand-in-hand to a polling place is a—very cute—metaphor for the impossibility of casting a vote that’s truly one’s own.