Cited but Not Causal: A Counterfactual Audit of Refusal Explanations in Aligned Language Models

Minje Kim, Keeheon Lee, Chi-Guhn Lee


Abstract
When an aligned language model declines a request, it almost always states a reason. Those reasons are read as evidence about the refusal, yet whether they name what actually triggered it has not been measured. We introduce a counterfactual audit of the cited reason, removing the reason-bearing feature to test necessity and inserting it into a benign prompt to test sufficiency. The two tests partition cited reasons into four kinds: faithful, over-cited, under-specified, and confabulated. We audit 22 models from nine developers on 840 prompts pooled from seven public safety benchmarks. Across the audited refusals, 57.2% cite a reason that fails at least one test, though faithful remains the largest category for 21 of 22 models. Over-citation is highest in the models that refuse most broadly. Paired sweeps over two families’ post-training checkpoints place its rise at supervised fine-tuning, not at later preference optimization. Probes on open-weight models tie these labels to internal representations. Category rates hold under a different-family judge, and the faithful-versus-over-cited ordering holds under an own-reason audit. We release the framework, the counterfactual variants, and per-model labels.
Anthology ID:
2026.emnlp-main.645
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
Note:
Pages:
14854–14877
Language:
URL:
https://aclanthology.org/2026.emnlp-main.645/
DOI:
Bibkey:
Cite (ACL):
Minje Kim, Keeheon Lee, and Chi-Guhn Lee. 2026. Cited but Not Causal: A Counterfactual Audit of Refusal Explanations in Aligned Language Models. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 14854–14877, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Cited but Not Causal: A Counterfactual Audit of Refusal Explanations in Aligned Language Models (Kim et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.645.pdf