Disentangling Form and World Knowledge in LLM Interpretation: Evidence from Quantifier Scope Disambiguation

Jakub Kosterna, Justyna Grudzińska, Maciej Miecznikowski, Wojciech Borysewicz, Julia Poteralska, Kacper Rutkowski, Jan Henryk Kwapisz


Abstract
We investigate how large language models (LLMs) construct meaning using Quantifier Scope Disambiguation (QSD) as a controlled probing task. We introduce (i) a balanced English corpus designed to neutralize classical surface heuristics and systematically manipulate the relationship between formal predictors and preferred readings, and (ii) a pseudosentence dataset that attenuates world-knowledge cues while preserving formal information relevant to scope. In Experiment 1, we evaluate a range of LLMs in a zero-shot question-answering setup and compare them to human baselines. While models achieve high accuracy on the balanced corpus, performance drops substantially on pseudosentences. Crucially, robust performance is retained only when classical formal predictors converge on the preferred reading; once these predictors partially diverge or fully conflict, performance approaches chance levels and becomes highly unstable across models. These findings suggest that the strong QSD performance reported for current LLMs may reflect a masking effect caused by the systematic alignment of surface-level heuristics and world knowledge in naturalistic datasets. As an exploratory extension, Experiment 2 examines whether adding externally retrieved context changes model behavior while keeping the task and prompt fixed. RAG has a negligible aggregate effect, with the largest positive change occurring in the hardest configuration, where surface cues are maximally misleading. Taken together, our results suggest that high QSD performance in LLMs remains strongly dependent on convergence between formal cues and world knowledge, despite the apparent semantic robustness suggested by naturalistic QSD results.
Anthology ID:
2026.findings-emnlp.985
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
20823–20833
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.985/
DOI:
10.18653/2026.findings-emnlp.985
Bibkey:
Cite (ACL):
Jakub Kosterna, Justyna Grudzińska, Maciej Miecznikowski, Wojciech Borysewicz, Julia Poteralska, Kacper Rutkowski, and Jan Henryk Kwapisz. 2026. Disentangling Form and World Knowledge in LLM Interpretation: Evidence from Quantifier Scope Disambiguation. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 20823–20833, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Disentangling Form and World Knowledge in LLM Interpretation: Evidence from Quantifier Scope Disambiguation (Kosterna et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.985.pdf