Love, Hate, or Both? How Affective Polarization Shapes Responses to Party Cues

Party labels powerfully shape how citizens interpret political information, yet we still lack clarity on the affective mechanisms driving these effects. Dual-process theories emphasize that party cues work as low-effort heuristics, while motivated reasoning frameworks highlight emotionally charged, goal-directed processing. Although party endorsements demonstrably shift policy judgments, we know much less about which specific types of partisan sentiment actually drive cue-taking: warmth toward one's own party, animosity toward rivals, or their combination as affective polarization. This question is especially underexplored in multiparty democracies. This preregistered study reports the design of a within-subjects survey experiment to be fielded in early 2026 in Finland (N ≈ 2,000). Respondents are recruited from a national online panel with quotas for age, gender, and region. Each participant evaluates eight brief policy proposals covering economic, social, and security issues. For every respondent, two proposals appear without any party label (baseline), two are endorsed by their most-preferred party (in-party cue), two by a party they would support in coalition but do not identify with most strongly (coalition-party cue), and two by their least-preferred party (out-party cue). A ninth filler vignette reduces the risk that participants guess the study's purpose. Vignette order, cue assignment, and specific party selection are randomized individually. Before seeing proposals, respondents answer questions about demographics, political interest, party identification (CSES format), like–dislike ratings for all parliamentary parties (0–10 scales), coalition preferences, and left–right self-placement. From these we identify each person's in-party, coalition-party, and out-party, and construct continuous measures of in-party warmth, out-party hostility, and affective polarization (the gap between warmest and coldest party ratings). Policy support is measured on 7-point scales. Our main predictions are that (H1a) in-party endorsements increase support compared to the no-label baseline; (H1b) out-party endorsements decrease support; (H1c) coalition-party endorsements also increase support, but less than direct in-party endorsements. We also predict that people's affective profiles shape how strongly they respond to cues: (H2a) individuals who score high on both in-party warmth and out-party hostility show the strongest cue effects—they boost support when their party or a coalition partner endorses a policy, and sharply reduce support when an opposing party does; (H2b) those high only in in-party warmth respond most to their own party and coalition partners; (H2c) those high only in out-party hostility show pronounced rejection of opposing party cues but weaker positive responses to their own party; (H2d) individuals low on both dimensions show minimal sensitivity to any party cues. Our study clarifies whether party cue-taking operates through affective transfer and which sentiment configurations genuinely matter. For democratic politics, it illuminates how affective polarization shapes information processing in multiparty systems—if citizens reject policies simply because they come from disliked parties, this signals judgment driven by group identity rather than substance, potentially deepening misperceptions and constraining cross-party cooperation.