In his 2008 book, The Big Sort: Why the Clustering of Like-Minded America is Tearing Us Apart, Bill Bishop describes how Americans have been increasingly sorting themselves into geographic groups based on distinct choices in lifestyle and ideology. He argues that such ‘sorting,’ or self-segregation, contributes to political polarization. According to Bishop, “everyone can choose the neighbors (and church and news shows) most compatible with his or her lifestyle and beliefs. And we are living with the consequences of this segregation by way of life: pockets of like-minded citizens that have become so ideologically inbred that we don’t know, can’t understand, and can barely conceive of ‘those people’ who live just a few miles away.” Such segmentation of American society may be unavoidable, and comes with serious repercussions.

The results of the Harvard Public Opinion Project’s (HPOP) March poll of young adults (ages 18 to 29) in America may provide new evidence to support Bishop’s claim that we are living in silos. The poll asked respondents whether they had a close relationship with various types of people, and the results demonstrated that “blacks and whites, young Democrats and Republicans, have relationships with very different groups of people.” Most strikingly, the poll found that 75 percent of young Democrats have a relationship with a Hillary Clinton supporter, yet only 39 percent of them have a relationship with a Donald Trump supporter. This finding, that disparate social groups are interacting with a relatively narrow range of people, is possibly due to the geographic sorting that Bishop illustrates. It is clear that individuals are increasingly living within ideological boundaries, as the percentage of voters who live in solidly Democratic or Republican counties rose from 26.8 percent in 1976 to 50 percent in 2012 and then rose again to 60 percent in 2016.

The poll also discovered significant differences in lifestyle choices among young Democrats and Republicans. For instance, 80 percent of young Republicans know someone who is a gun owner while only 49 percent of young Democrats do. It is not a stretch to conclude, as Bishop does, that such variety in whom we know and interact with has powerful implications for our political views. Again, while not necessarily the only causal force, it is at least plausible that geographic sorting is contributing to these differences among Democrats and Republicans. In fact, political scientist Wendy K. Tam Cho studied voter migration data and found that “while it may not be the only factor, partisan sorting is a significant component of destination decisions” for both Republicans and Democrats. This finding is substantiated by evidence that densely-populated regions are becoming more Democratic, and less dense areas are becoming more Republican.

The fact that different groups of people have such varying relationships is significant because, as HPOP determined, these relationships can alter “views toward President Trump’s agenda.” As proof of this point, 63 percent of those with a close relationship to a police officer thought that halting “the ‘anti-police’ atmosphere in America” would improve the country, while only 41 percent of those who are not close to a police officer said the same. While the conclusion that “who you know” affects political views is somewhat intuitive and unsurprising, it does serve as a reminder that making an effort to interact with people who are not like you is beneficial. At a basic level, Democrats should get to know more Trump supporters, and Republicans should get to know more Clinton supporters.

The findings of the HPOP poll are somewhat disturbing, in that they reveal fragmentation among young adult Americans. Unfortunately, our natural inclination to connect with like-minded individuals makes it difficult to limit the self-sorting that the poll and Bishop report. While there may be no way to fully reverse such self-segregation, interaction between individuals with different lifestyles and political beliefs should be encouraged. A sincere attempt to understand people who are different from you is one of the best tools for fighting polarization. As Bishop warned in his book, “heterogeneous communities restrain group excesses; homogeneous communities march toward the extremes.” Ultimately, HPOP’s poll demonstrates that different groups of people often operate in separate social worlds and we therefore must heed Bishop’s warning.