🔎 What the paper shows

This study argues that social closure between higher- and lower-educated citizens — meaning large shares of people have few or no close ties to differently educated others — strengthens and reinforces differences in immigration attitudes and in voting for new left or far-right parties across Western democracies.

📍 Where the evidence comes from

• Social network data from the Netherlands documenting that substantial proportions of higher- and lower-educated citizens report no close relationships with people of different education levels.
• European Social Survey (ESS) data linking individuals' reported network education composition to their immigration attitudes and vote choice.

🧭 How the relationship was tested

• Network education composition is used as a predictor of immigration attitudes and voting behavior.
• Difference-in-differences models examine within-person change: when an individual's network education mix changes, corresponding changes in immigration attitudes and voting are observed, consistent with network effects on political preferences.

📈 Key findings

• Many respondents have educationally homogenous personal networks.
• Network education levels predict both immigration attitudes and support for new left or far-right parties.
• Changes in network education composition are associated with changes in those attitudes and voting patterns, supporting the role of peer effects in reinforcing educational divides.

⚖️ Why this matters

These findings link literatures on educational divides and peer influence and support interpreting political competition on the universalist–particularist dimension as durably rooted in social structure. In practice, sizable, distinct, and insulated educational groups can crystallize contemporary political divides and predictably shape political outcomes.