Evaluating Communicative Belief Updates in Large Language Models via Implicature Recognition and Cancellation

Cesare Spinoso-Di Piano, Verna Dankers, Marius Mosbach, Jackie Chi Kit Cheung


Abstract
Human language is driven by unspoken beliefs and belief updates which are thus of critical importance for successful interactions between large language models (LLMs) and their users. In this paper, we evaluate the ability of LLMs to recognize unspoken beliefs made through implicatures and to recognize their updates through implicature cancellation: the pragmatic phenomenon whereby an utterance’s implied meaning is weakened or negated. We create the first expert-annotated implicature cancellation dataset, ImplicatureX, crowdsourced for human judgements of implicatures and their corresponding cancellations. We find that LLM belief update understanding lags behind that of humans, especially in more naturally-occurring scenarios. Additional control experiments suggest that successes in LLM belief updates may in part stem from a reliance on prior beliefs, and that failures in belief updates may depend on their type and on their form. Overall, our study suggests that current LLMs have not yet reached human-level understanding of communicative belief updates.
Anthology ID:
2026.emnlp-main.139
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
3192–3217
Language:
URL:
https://aclanthology.org/2026.emnlp-main.139/
DOI:
Bibkey:
Cite (ACL):
Cesare Spinoso-Di Piano, Verna Dankers, Marius Mosbach, and Jackie Chi Kit Cheung. 2026. Evaluating Communicative Belief Updates in Large Language Models via Implicature Recognition and Cancellation. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 3192–3217, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Evaluating Communicative Belief Updates in Large Language Models via Implicature Recognition and Cancellation (Spinoso-Di Piano et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.139.pdf