Efficiently Computing Susceptibility to Context in Language Models

Tianyu Liu, Kevin Du, Mrinmaya Sachan, Ryan Cotterell


Abstract
One strength of modern language models is their ability to incorporate information from a user-input context when answering queries. However, they are not equally sensitive to the subtle changes to that context.To quantify this, Du et al. (2024) gives an information-theoretic metric to measure such sensitivity. Their metric, susceptibility, is defined as the degree to which contexts can influence a model’s response to a query at a distributional level.However, exactly computing susceptibility is difficult and, thus, Du et al. (2024) falls back on a Monte Carlo approximation.Due to the large number of samples required, the Monte Carlo approximation is inefficient in practice. As a faster alternative, we propose Fisher susceptibility, an efficient method to estimate the susceptibility based on Fisher information.Empirically, we validate that Fisher susceptibility is comparable to Monte Carlo estimated susceptibility across a diverse set of query domains despite its being 70× faster.Exploiting the improved efficiency, we apply Fisher susceptibility to analyze factors affecting the susceptibility of language models.We observe that larger models are as susceptible as smaller ones.
Anthology ID:
2024.findings-emnlp.386
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2024
Month:
November
Year:
2024
Address:
Miami, Florida, USA
Editors:
Yaser Al-Onaizan, Mohit Bansal, Yun-Nung Chen
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
6615–6626
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URL:
https://aclanthology.org/2024.findings-emnlp.386
DOI:
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Cite (ACL):
Tianyu Liu, Kevin Du, Mrinmaya Sachan, and Ryan Cotterell. 2024. Efficiently Computing Susceptibility to Context in Language Models. In Findings of the Association for Computational Linguistics: EMNLP 2024, pages 6615–6626, Miami, Florida, USA. Association for Computational Linguistics.
Cite (Informal):
Efficiently Computing Susceptibility to Context in Language Models (Liu et al., Findings 2024)
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https://aclanthology.org/2024.findings-emnlp.386.pdf