LLMs and their Limited Theory of Mind: Evaluating Mental State Annotations in Situated Dialogue

Katharine Kowalyshyn, Matthias Scheutz


Abstract
Effective human teams excel at maintaining a consistent shared mental model (SMM) that reflects the shared understanding of individual team members about the task and what remains to be done. We present a novel, two-step framework that leverages large language models (LLMs) both as (1) annotators of team dialogues to track the team’s SMM and (2) as automated discrepancy detectors among individuals’ mental states as they are represented in individual mental models. We define an SMM coherence evaluation framework for this use case and apply it to six dialogues in a previously published team corpus, ultimately producing a dataset of human and LLM SMM annotations, a reproducible evaluation framework for SMM coherence, and an empirical assessment of LLM-based discrepancy detection. Our results reveal that while LLMs exhibit apparent coherence on straightforward natural-language annotation tasks, they systematically err in scenarios requiring spatial reasoning or disambiguation of transcription-level disfluencies.
Anthology ID:
2026.sigdial-1.52
Volume:
Proceedings of the 27th Annual Meeting of the Special Interest Group on Discourse and Dialogue
Month:
August
Year:
2026
Address:
Atlanta, Georgia, USA
Editors:
Jinho D. Choi, Yun-Nung Chen, Kotaro Funakoshi, Ali Emami
Venue:
SIGDIAL
SIG:
SIGDIAL
Publisher:
Association for Computational Linguistics
Note:
Pages:
738–756
Language:
URL:
https://aclanthology.org/2026.sigdial-1.52/
DOI:
Bibkey:
Cite (ACL):
Katharine Kowalyshyn and Matthias Scheutz. 2026. LLMs and their Limited Theory of Mind: Evaluating Mental State Annotations in Situated Dialogue. In Proceedings of the 27th Annual Meeting of the Special Interest Group on Discourse and Dialogue, pages 738–756, Atlanta, Georgia, USA. Association for Computational Linguistics.
Cite (Informal):
LLMs and their Limited Theory of Mind: Evaluating Mental State Annotations in Situated Dialogue (Kowalyshyn & Scheutz, SIGDIAL 2026)
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PDF:
https://aclanthology.org/2026.sigdial-1.52.pdf