You Don’t Understand: Benchmarking Responses to Experiential Mismatch in LLMs

Yuyang Dai


Abstract
Current LLM evaluation frameworks primarily assess understanding through task performance, focusing on factual accuracy, reasoning, and instruction following, while overlooking the experiential dimensions of human comprehension. Models that produce fluent, empathetic responses score highly even when they claim experiential access they cannot possess. We introduce ComprehensionGap, a benchmark of 500 scenarios spanning five empirically grounded categories of experiential incommensurability: Embodied Qualia, Episodic Incommensurability, Cultural Tacit Knowledge, Relational Situatedness, and Existential Finitude. Using a human-judged protocol measuring Acknowledgement of Limit, Absence of False Empathy, and Situational Relevance, we evaluate six frontier and open-weight models. Our experiments reveal a consistent Grounding Gap: all models maintain high fluency while systematically overclaiming experiential understanding, with larger models producing more convincing yet less honest mimicry. Models can calibrate for information gaps but not experiential ones. These findings argue for integrating experiential calibration into future alignment and evaluation frameworks.
Anthology ID:
2026.aacl-short.31
Volume:
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 2: Short Papers)
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venues:
AACL | IJCNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
463–473
Language:
URL:
https://aclanthology.org/2026.aacl-short.31/
DOI:
Bibkey:
Cite (ACL):
Yuyang Dai. 2026. You Don’t Understand: Benchmarking Responses to Experiential Mismatch in LLMs. In Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 2: Short Papers), pages 463–473, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
You Don’t Understand: Benchmarking Responses to Experiential Mismatch in LLMs (Dai, AACL-IJCNLP 2026)
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PDF:
https://aclanthology.org/2026.aacl-short.31.pdf