How Do Drivers React to Partisan Bumper Stickers? Understanding Polarization in Apolitical Settings Authors: Rachel Suzanne Torres, Benjamin David Farrer Published in: Frontiers in Political Science, Volume 7, 2025 DOI: 10.3389/fpos.2025.1617785 --- Overview This original research article investigates how partisan bumper stickers influence drivers' behavior, especially whether exposure to out-party (opposing partisan) bumper stickers triggers hostility and affects driving conduct. The study focuses on political polarization's spillover effects in everyday, seemingly apolitical settings like driving. --- Key Questions Does seeing a partisan bumper sticker trigger partisan identity and change driving behavior? Are drivers more hostile towards bad drivers who display out-party bumper stickers? Does the race of the driver affect the intensity of reactions to bad driving coupled with partisan bumper stickers? --- Background Bumper stickers are a common form of self-expression, particularly political ones. Political polarization, especially in the U.S., has penetrated social and everyday interactions beyond formal political spaces. Previous research focuses on why people display bumper stickers, not how they react to them. Driving is a context where negativity and hostility often manifest due to inconveniences and anonymity. --- Hypotheses H1: Drivers will show more hostility (e.g., higher likelihood of honking) towards bad drivers displaying out-partisan bumper stickers than bad drivers with in-party, non-partisan, or no bumper stickers. H2: White participants will show increased hostile responses to bad drivers with out-partisan stickers if the driver is Black, reflecting racialized perceptions and permission structures for hostility. --- Methods Design: Online survey experiment using Amazon Mechanical Turk with U.S. adult participants. Procedure: Pre-treatment survey capturing demographics, political partisanship, personality (agreeableness, authoritarianism), and self-assessed driving quality. Treatment: Participants view a 20-30 second computer-generated dashcam video featuring an orange car driving either well or badly. The car displays one of four bumper sticker conditions: none, neutral ("I Love My Dog"), Democrat, or Republican. After the video, participants see a simulated driver’s license showing the driver’s race (Black or White) and sex (male or female). Post-treatment survey measures likelihood of honking and feeling thermometer ratings (general warmth/hostility towards the driver). Sample: After filtering for quality, 895 participants remained. Treatments: 48 groups combining driving quality (good/bad), bumper sticker type (4 types), race (Black/White), and sex (male/female). --- Results Hypothesis 1 (H1) Findings Hostility measured by: Likelihood of honking horn at the driver. Feeling thermometer ratings (warmer ratings indicate less hostility). Key findings: No significant bumper sticker effect when the driver is driving well. When the driver is driving badly, presence of an out-partisan bumper sticker significantly increases: Likelihood of honking horn (from 2.59 to 3.12 on a 5-point scale). Hostile feelings (thermometer rating drops from ~69.5 to ~52.7). Bumper stickers trigger hostility mainly in negative driving interactions and mostly towards out-partisans. Neutral bumper stickers (like "I Love My Dog") showed overlapping confidence intervals with out-party stickers, suggesting more research needed on neutral vs partisan effects. Hypothesis 2 (H2) Findings Analysis limited to white respondents comparing responses to Black vs. White drivers. Patterns similar to H1 in both racial groups. Slightly higher hostility (horn honking) toward bad, out-partisan Black drivers than white