The Geometry of Political Abstraction in Large Language Models

Noé Durandard, Saurabh Dhawan, Thierry Poibeau


Abstract
Large language models encode high-level concepts with heterogeneous domain-specific manifestations, but it remains unclear whether their internal representations are organized in a form that supports cross-domain generalization. We investigate this question by adapting representational geometry methods from systems neuroscience and using political ideology as a naturalistic test case for a candidate latent variable spanning diverse policy domains. Across three open-weight LLMs, we analyze hidden states elicited by matched left- and right-leaning statements from ten policy domains. Within each domain, while political polarity is linearly decodable, lexical features achieve comparable performance. By contrast, cross-domain generalization substantially exceeds the lexical baseline and peaks in intermediate layers. This peak coincides with a marked reduction in participation ratio, suggesting that domain-specific political distinctions, instead of being maintained as independent axes, become aligned within a shared low-dimensional subspace. These findings suggest that LLMs transiently organize heterogeneous inputs into a common representational geometry that supports cross-domain abstraction, offering insight into how models structure complex social knowledge.
Anthology ID:
2026.blackboxnlp-1.43
Volume:
Proceedings of the 9th BlackboxNLP Workshop: Analyzing and Interpreting Neural Networks for NLP
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Dana Arad, Yonatan Belinkov, Hanjie Chen, Nils Feldhus, Aaron Mueller, Hosein Mohebbi, Gabriele Sarti, Martin Tutek
Venues:
BlackboxNLP | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
739–760
Language:
URL:
https://aclanthology.org/2026.blackboxnlp-1.43/
DOI:
Bibkey:
Cite (ACL):
Noé Durandard, Saurabh Dhawan, and Thierry Poibeau. 2026. The Geometry of Political Abstraction in Large Language Models. In Proceedings of the 9th BlackboxNLP Workshop: Analyzing and Interpreting Neural Networks for NLP, pages 739–760, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
The Geometry of Political Abstraction in Large Language Models (Durandard et al., BlackboxNLP 2026)
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PDF:
https://aclanthology.org/2026.blackboxnlp-1.43.pdf