Jacob Brown is the first BU faculty member to receive an Andrew Carnegie Fellowship since its founding in 2015.

Partisan Politics

You’ve Heard of Red States and Blue States. But What About Red and Blue Neighborhoods?

Research by BU political scientist and Andrew Carnegie Fellowship winner Jacob Brown shows that where you live might have a lot of influence on partisan divides and how you vote

America is famous for its so-called red states and blue states—territories in which a majority of residents reliably vote Republican or Democrat, respectively, during elections. But does the political partisanship go deeper than that? Research by Boston University political scientist Jacob Brown shows that there are even red and blue neighborhoods—and that the section of town you live in might influence how you vote. 

“There’s evidence that there are some conformity behavioral effects that you can observe in political behavior,” says Brown, a College of Arts & Sciences assistant professor of political science. “When people live in more Democratic or Republican places, they become more likely to register the way their neighbors are registering. They become more likely to donate to the party of the homogenous community that they’re in. And then you also see there’s an activating effect: if you’re a steadfast Democrat, and you live around more Democrats, you might participate a little bit more in politics than you would otherwise.” 

In today’s highly polarized political environment, Brown’s research has piqued lots of interest from other researchers, reporters, and policymakers. Most recently, it’s earned him recognition among this year’s Andrew Carnegie Fellows, a prestigious award that supports high-caliber scholarship and research in the social sciences and humanities that addresses important and enduring issues confronting our society. Fellows each receive a stipend of $200,000, allowing them to devote significant time to research and writing.

Brown is the first BU faculty member to receive the fellowship—which is given by the Carnegie Corporation of New York—since the program’s founding in 2015.

“The recognition is really gratifying, and I appreciate their interest and confidence in the work,” he says. “Getting access to resources I normally couldn’t muster, including rich sources of data, opens up so many possibilities.” 

In his current project, Brown is curious: Does political homogeneity perpetuate itself, with voters becoming more similar politically to the people they live around? Does living in politically homogeneous communities make voters more polarized in how they view politics?

To find answers, Brown is starting at the beginning: childhood. He and other research collaborators are analyzing longitudinal data to determine if where someone grew up—and specifically the prevailing politics of that area—affect their political viewpoint as an adult. Brown and his colleagues connected data about young people entering the electorate—specifically, their party affiliations—to where those young people lived as children. (They can break the data down further, too, by analyzing how long someone lived at a particular address, and roughly what age they were.) So far, the test results show that people who spend more time in staunchly Republican or Democratic areas are more likely to become a Republican or Democrat themselves, respectively. 

“The idea is that there’s this exposure effect during childhood—that your place is influencing who you become politically,” Brown says.

The next research frontier for Brown is to investigate if this partisan entrenchment creates greater hostility toward the other side. Does someone who grew up in a deep red neighborhood feel more animosity toward Democrats than someone who came from a purple community? 

This is, admittedly, trickier to determine, Brown says. He and his colleagues are using online speech as a proxy for political feelings by combing X—formerly Twitter—data for political speech. Some posts on the social platform are geotagged, meaning the researchers can isolate the neighborhood they came from. 

“We’ve coded their [X posts] as being more or less hostile when they talk about politics, compared to other topics, to see how that tracks with the geographic composition of the places they’re tweeting from,” Brown says. “So, it’s one way of trying to get at what is a pretty hard thing to measure, which is how negative someone feels about politics on the other side.”

Brown’s work—understanding the roots of political partisan segregation and its consequences—is essential at a time when partisan divides in the US are almost higher than ever. According to Brown and other researchers, partisan segregation has been steadily, and durably, increasing over time.

And all of it is contributing to the pervasive sense among Republicans and Democrats alike that politics is gridlocked and broken. 

“There’s a good amount of research in political science that many different areas of politics become more imbalanced when we have a geographically segregated electorate,” Brown says. “It makes it harder to draw districts in a way that ensures fair representation. It reduces electoral competition, and can contribute to polarization in Congress. When cities and suburbs are more polarized, it’s harder to get the regional cooperation required to invest in different public goods, like transit or other kinds of infrastructure.”

Amid all the negative outcomes, Brown sees a ray of hope: spending more time in politically mixed neighborhoods and communities seems to encourage people to find commonalities, especially in the form of local policy interests, where there often can be much more bipartisan agreement than seen at the national level. 

“As much conflict as you see in politics now, I’m generally much more interested in the potential for cross-partisan exposure. There seem to be benefits from more mixed places and more shared geographic interests, and that’s something I see as positive, for sure,” he says.