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Main Authors: Möller, Lucas, Nikolaev, Dmitry, Padó, Sebastian
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2402.02883
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author Möller, Lucas
Nikolaev, Dmitry
Padó, Sebastian
author_facet Möller, Lucas
Nikolaev, Dmitry
Padó, Sebastian
contents Siamese encoders such as sentence transformers are among the least understood deep models. Established attribution methods cannot tackle this model class since it compares two inputs rather than processing a single one. To address this gap, we have recently proposed an attribution method specifically for Siamese encoders (Möller et al., 2023). However, it requires models to be adjusted and fine-tuned and therefore cannot be directly applied to off-the-shelf models. In this work, we reassess these restrictions and propose (i) a model with exact attribution ability that retains the original model's predictive performance and (ii) a way to compute approximate attributions for off-the-shelf models. We extensively compare approximate and exact attributions and use them to analyze the models' attendance to different linguistic aspects. We gain insights into which syntactic roles Siamese transformers attend to, confirm that they mostly ignore negation, explore how they judge semantically opposite adjectives, and find that they exhibit lexical bias.
format Preprint
id arxiv_https___arxiv_org_abs_2402_02883
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Approximate Attributions for Off-the-Shelf Siamese Transformers
Möller, Lucas
Nikolaev, Dmitry
Padó, Sebastian
Computation and Language
Machine Learning
Siamese encoders such as sentence transformers are among the least understood deep models. Established attribution methods cannot tackle this model class since it compares two inputs rather than processing a single one. To address this gap, we have recently proposed an attribution method specifically for Siamese encoders (Möller et al., 2023). However, it requires models to be adjusted and fine-tuned and therefore cannot be directly applied to off-the-shelf models. In this work, we reassess these restrictions and propose (i) a model with exact attribution ability that retains the original model's predictive performance and (ii) a way to compute approximate attributions for off-the-shelf models. We extensively compare approximate and exact attributions and use them to analyze the models' attendance to different linguistic aspects. We gain insights into which syntactic roles Siamese transformers attend to, confirm that they mostly ignore negation, explore how they judge semantically opposite adjectives, and find that they exhibit lexical bias.
title Approximate Attributions for Off-the-Shelf Siamese Transformers
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2402.02883