Can Large Language Models Faithfully Express Their Intrinsic Uncertainty in Words?

Gal Yona, Roee Aharoni, Mor Geva


Abstract
We posit that large language models (LLMs) should be capable of expressing their intrinsic uncertainty in natural language. For example, if the LLM is equally likely to output two contradicting answers to the same question, then its generated response should reflect this uncertainty by hedging its answer (e.g., “I’m not sure, but I think...”). We formalize faithful response uncertainty based on the gap between the model’s intrinsic confidence in the assertions it makes and the decisiveness by which they are conveyed. This example-level metric reliably indicates whether the model reflects its uncertainty, as it penalizes both excessive and insufficient hedging. We evaluate a variety of aligned LLMs at faithfully conveying uncertainty on several knowledge-intensive question answering tasks. Our results provide strong evidence that modern LLMs are poor at faithfully conveying their uncertainty, and that better alignment is necessary to improve their trustworthiness.
Anthology ID:
2024.emnlp-main.443
Volume:
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2024
Address:
Miami, Florida, USA
Editors:
Yaser Al-Onaizan, Mohit Bansal, Yun-Nung Chen
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
7752–7764
Language:
URL:
https://aclanthology.org/2024.emnlp-main.443
DOI:
Bibkey:
Cite (ACL):
Gal Yona, Roee Aharoni, and Mor Geva. 2024. Can Large Language Models Faithfully Express Their Intrinsic Uncertainty in Words?. In Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing, pages 7752–7764, Miami, Florida, USA. Association for Computational Linguistics.
Cite (Informal):
Can Large Language Models Faithfully Express Their Intrinsic Uncertainty in Words? (Yona et al., EMNLP 2024)
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PDF:
https://aclanthology.org/2024.emnlp-main.443.pdf