# Similarity judgements: the comparison of normative predictions and subjective evaluations – A study of the ratio model of similarity in social context

## TL;DR

This study compares how people judge similarity to ideal and bad politicians with a theoretical model, finding that people's judgments differ, especially for favorable candidates.

## Contribution

The study reveals a negativity effect in similarity judgments, showing the ratio model's limitations for favorable candidates.

## Key findings

- Subjective similarity judgments deviated from theoretical predictions, especially for positively featured candidates.
- Additional positive features reduced perceived similarity to ideal politicians, but negative features had little effect.
- The ratio model works better for unfavorable candidates, highlighting the role of feature valence in judgments.

## Abstract

This study examines the consistency between subjective similarity evaluations and the theoretical predictions derived from Tversky’s ratio model of similarity, alongside the impact of additional positive and negative features on perceived similarity to ideal and bad politicians.

Using a sample of 120 participants, we assessed the similarity of eight candidate profiles to an ideal and bad politician, varying in positive and negative features. Participants’ subjective evaluations were compared with theoretical predictions derived from Tversky’s ratio model. The analysis focused on how candidate and referent valence influenced observed versus theoretical similarity.

Subjective similarity judgments deviated systematically from theoretical predictions, especially for positively featured candidates, indicating a negativity effect. Additional positive features decreased the perceived similarity of favorable candidates to an ideal politician, while additional negative features did not significantly affect similarity judgments of unfavorable candidates.

Our findings underscore a significant disparity between subjective and objective similarity judgments, notably for favorable candidates. While the ratio model performs well for unfavorable candidates, its applicability diminishes for favorable ones, emphasizing the role of feature valence in decision-making. Further research on feature valence is crucial for a comprehensive understanding across contexts.