What truly fuels intense partisan hostility in the U.S.? Is it an emotional reaction against the opposing party itself, or is policy disagreement the primary driver?

Experimental Approach:

This research employs a set of carefully designed vignette evaluations. Participants assessed their reactions to political content under varied conditions—both with and without explicit partisanship cues.

🔍 Shared Partisanship vs. Shared Policy Preference:

The effects of partisan identification alone were found to be about 71% as strong as shared policy preference when presented separately.

🧬 Randomized Elements & Counterfactuals:

However, the real test involved presenting randomized combinations of party and policy stances together. This approach allowed us to isolate their independent impacts.

📊 Key Findings: Policy Dominance:

When partisan identity was paired with a policy stance (even unrelated ones), its effect nearly vanished—reducing by 52%. Meanwhile, policy disagreement effects remained substantial, decreasing minimally by about 10%.

💡 Why This Matters:

These results suggest that many current measures of partisan animosity may be capturing programmatic conflict rather than deep-seated social identity hostility. The findings highlight the need for more nuanced research designs in political science to accurately distinguish between these potentially distinct drivers of polarization.