Is modern society truly more politically polarized, or is it just an illusion fueled by sensationalist media and social networks? Daniel DellaPosta’s research, published in the American Sociological Review, provides a surprising answer. Instead of thinking of polarization as a strengthening of existing divisions, he offers a different metaphor: polarization spreads like an oil spill—starting in one place and gradually expanding until it covers a far larger area than initially expected.
The Problem with How We Measure Polarization
Traditional approaches to studying political polarization assume that political factions become more extreme in their existing positions—liberals become more liberal, and conservatives become more conservative. But when examining public opinion data over time, the picture is less clear. DellaPosta highlights that conventional measures of polarization do not show a dramatic shift toward more extreme beliefs in the general population. Most people still hold a mix of views, some of which do not neatly fit into "left" or "right" categories.
Oil Spill vs. High Fences
DellaPosta proposes that polarization should not be understood as a sharpening of individual ideological stances but as a restructuring of how our beliefs are interconnected. In the past, people could disagree on some issues but find common ground on others—for example, supporting higher taxes while also advocating for gun rights. Today, opinions tend to cluster into coherent packages. If you know someone’s stance on climate change, you are now far more likely to predict their views on abortion, immigration, or LGBTQ+ rights.
This is what DellaPosta refers to as the "oil spill model." Political attitudes are not becoming more extreme individually, but rather they are spreading and clustering together, making it harder to find ideological overlap between different groups.
How Did This Happen?
To test his theory, DellaPosta used data from the General Social Survey, which has tracked American public opinion since 1972. Instead of analyzing each issue separately, he created a network of beliefs—a system mapping out how different opinions are interconnected and how those connections have evolved over time.
The results reveal that over the last few decades, public opinion has become more tightly clustered. Views that were once independent of each other have increasingly aligned into distinct ideological packages. This means that when someone identifies as liberal or conservative, their entire belief system is more likely to match a predefined template rather than a mix of personal convictions.
What Are the Consequences?
DellaPosta’s findings help explain why political discourse has become so difficult. In the past, people with opposing views on economic policy, for example, could still find common ground on foreign policy. Today, however, if you disagree with someone on one issue, you are likely to disagree with them on almost everything else as well.
This has profound implications for democracy. It suggests that political identities have become more rigid, making bipartisan cooperation and compromise much harder. Social and media environments reinforce this effect by creating echo chambers, where exposure to opposing viewpoints is minimal, and beliefs become even more entrenched.
Is There a Way Back?
While DellaPosta’s research provides a compelling explanation for the rise in polarization, it does not offer a straightforward solution. As new issues become politicized—such as attitudes toward science, technology, or even lifestyle choices—polarization may continue to deepen.
However, by understanding that polarization is not just about growing differences but about the way opinions are structured, we may be able to design better strategies for fostering dialogue and breaking down rigid ideological clusters. Instead of focusing solely on countering extremism, efforts to bridge political divides might be more effective if they focus on disrupting the links between issues and encouraging more independent thinking.
The oil spill is spreading, but recognizing its patterns may be the first step toward cleaning it up.
