Bubbles

Many people say that Americans increasingly live in "bubbles" in which they don't encounter people whose political views differ from their own.  To quote a NY Times article that appeared a few weeks ago, "years of social and political sorting have left Americans of both parties less likely to know people who are different from them politically."  It didn't cite a source for this statement, but I have been looking for relevant survey evidence for some time and have found only the following.

1.  Pew surveys from 2016 and 2017 asked "Thinking about your close friends, how many are...Democrats--a lot, some, just a few or none?" and a parallel question about how many were Republicans. 
2. In 2007, a CBS/NY Times survey asked Republicans "Do any of your close friends think of themselves as Democrats?" and asked Democrats if any close friends thought of themselves as Republicans. 
3.  And way back in 1952, the American National Election Study asked how people thought their five closes friends would vote.

Those questions are all on the same general topic, but they can't be directly compared, so it's not clear whether there's actually been a change.  For what it's worth, the 1952 results were 28% thought all their friends would vote Democratic, 26% that all would vote Republican, 25% that they would be split, and 20% didn't know. 

But there is also a question of who is more or less likely to know people with different political views.  A number of people, notably David Brooks and Charles Murray, say that Democrats, more specifically college educated Democrats, are more likely to live in "bubbles." I looked at the 2017 Pew survey to see if there was any evidence for this.  I limited the analysis to non-blacks, because there was a large racial difference:  32% of blacks and only 5% of non-Hispanic whites said that none of their close friends were Republicans, while 7% of blacks and 31% of non-Hispanic whites said that a lot were.  Hispanics were in between, but a lot closer to non-Hispanic whites, so I kept them in. 

The results:  As expected, people report having more friends who support their party than support the other party.  On a scale of 1 (none) to 4 (a lot), with own party as rows and friends as columns, the means are:

                                 D            R
Democrats             3.48      2.46
Republicans           2.53      3.39


Republicans report more opposite-party friends and fewer same-party friends than Democrats, but the differences are small.  Educated people reported more own-party friends and more opposite party friends.  The differences were bigger for opposite party friends.  The general differences aren't surprising, since more educated people tend to have larger circles of friends, but it is notable that the differences are larger for the opposite party--I'll return to that. 

Finally, the relationship with education differs by party.  The relationship between education (1=HS or less, 2=some college, 3=college grad) and friends of one's own party, with Democrats as blue dots and Republicans as red:

Generally increasing with education for both, but the relationship is stronger for Democrats.

Now the relationship to opposite party friends:

Increasing for Republicans, little relationship for Democrats. 

As a table:
                                      Own        Opposite   Diff
HS, Rep                           3.26        2.38        0.88
Some, Rep                       3.47        2.46        1.01
College, Rep                    3.41        2.63        0.78

HS, Dem                          3.21        2.48        0.73
Some, Dem                      3.38        2.38        1.00
College, Dem                   3.59        2.48        1.11

If you take the difference between own-party and opposite-party friends as the measure, college-educated Democrats tend to have the thickest bubbles--score one for Brooks and Murray.  But if you take the number of opposite-party friends as the measure, then Republicans who didn't attend college and Democrats with some college have the thickest bubble (fewest friends from the other party). 

Most people don't like talking about politics, especially with people who don't agree with them.  So if you have a friend who shows signs of having different political views, you'll probably stay away from politics when you talk.  And even if you get a sense that the friend differs from you on some issues, you'll probably give them the benefit of the doubt and figure they're still a supporter of your party or at worst an independent.  Education tends to increase interest in politics and willingness to talk about politics, so more educated people are more likely to be aware of having friends who disagree with them. 
   
So I think the contrasting figures for college-educated Democrats and Republicans reflect the reality that college-educated people are now mostly Democratic.  Although non-college whites are now mostly Republicans, they are less likely to have accurate knowledge of their friends' political views, so there's little difference in the perceptions of Democrats and Republicans.