The Hidden Bias: A Study on Explicit and Implicit Political Stereotypes in Large Language Models
Paper · 2026 · Konrad Löhr, Shuzhou Yuan and Michael Färber
Summary
LLMs increasingly mediate how people find political information, so hidden ideological skews could quietly influence public opinion. This EACL 2026 Findings paper measures political bias in eight prominent LLMs with the two-dimensional Political Compass Test (PCT), which has an economic left–right axis and a social libertarian–authoritarian axis. The PCT's scoring rules are not public, so the authors first annotated each proposition's direction on both axes, using human annotators and several LLMs. With this transparent scoring, they ran three experiments. First, they recorded each model's baseline position. Second, they used persona prompting to surface explicit stereotypes about social groups. Third, they posed the PCT in several European languages to expose implicit, language-triggered stereotypes.
Every model landed on the left of the compass. Language-induced shifts were generally larger than persona-induced ones. For most models, the two kinds of stereotype pointed in the same direction, which suggests the models internally represent their own biases in a coherent way. The work implies that safety and bias audits run only in English can miss stronger biases that appear in other languages.
Key points
- Proposition annotations came from undergraduate students and three models: GPT-4.1-mini, Llama-4-Scout-17B-16E-Instruct and Llama-3.3-70B-Instruct. The models disagreed on just 5 of 120 annotations.
- Each of the 8 models was tested with 19 personas and 7 languages. All languages were European, and the personas included countries from the Anglosphere.
- Implicit bias produced the most striking shift in Gemini-2.0-flash, which moved toward a right-leaning, authoritarian position when prompted in French.
- Explicit and implicit stereotypes agreed for most models, but not for Gemini-2.0-flash and Gemini-2.0-flash-lite. For example, GPT-4.1-mini gave nearly identical shifts for an Italian-speaking persona (+0.092 economic, +0.644 social) and for Italian-language propositions (+0.158 economic, +0.644 social).
- The authors list several limitations: the PCT lacks psychometric validation, the language and region coverage is narrow, and structured prompts differ from real conversations. All generated data is released on GitHub.
Institutions
Fields, topics and concepts
📚 Shelves 6The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 worksSocial Sciences · 1,772 worksSafety Research · 543 works
🧭 Topics 2Research subjects and languages the work is about.Language models & pretraining · 3,320 worksBias, fairness & safety · 517 works
Cite
Cite as Konrad Löhr, Shuzhou Yuan and Michael Färber. 2026. The Hidden Bias: A Study on Explicit and Implicit Political Stereotypes in Large Language Models. Findings of the Association for Computational Linguistics: EACL 2026.
@inproceedings{lohr2026hidden,
title = {{The Hidden Bias: A Study on Explicit and Implicit Political Stereotypes in Large Language Models}},
author = {Konrad Löhr, Shuzhou Yuan and Michael Färber},
booktitle = {Findings of the Association for Computational Linguistics: EACL 2026},
year = {2026},
doi = {10.18653/v1/2026.findings-eacl.118},
url = {https://doi.org/10.18653/v1/2026.findings-eacl.118}
}References
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