Can Pretrained Language Models Derive Correct Semantics from Corrupt Subwords under Noise?

Xinzhe Li, Ming Liu, Shang Gao


Abstract
For Pretrained Language Models (PLMs), their susceptibility to noise has recently been linked to subword segmentation. However, it is unclear which aspects of segmentation affect their understanding. This study assesses the robustness of PLMs against various disrupted segmentation caused by noise. An evaluation framework for subword segmentation, named Contrastive Lexical Semantic (CoLeS) probe, is proposed. It provides a systematic categorization of segmentation corruption under noise and evaluation protocols by generating contrastive datasets with canonical-noisy word pairs. Experimental results indicate that PLMs are unable to accurately compute word meanings if the noise introduces completely different subwords, small subword fragments, or a large number of additional subwords, particularly when they are inserted within other subwords.
Anthology ID:
2023.starsem-1.15
Volume:
Proceedings of the 12th Joint Conference on Lexical and Computational Semantics (*SEM 2023)
Month:
July
Year:
2023
Address:
Toronto, Canada
Editors:
Alexis Palmer, Jose Camacho-collados
Venue:
*SEM
SIG:
SIGLEX
Publisher:
Association for Computational Linguistics
Note:
Pages:
165–173
Language:
URL:
https://aclanthology.org/2023.starsem-1.15
DOI:
10.18653/v1/2023.starsem-1.15
Bibkey:
Cite (ACL):
Xinzhe Li, Ming Liu, and Shang Gao. 2023. Can Pretrained Language Models Derive Correct Semantics from Corrupt Subwords under Noise?. In Proceedings of the 12th Joint Conference on Lexical and Computational Semantics (*SEM 2023), pages 165–173, Toronto, Canada. Association for Computational Linguistics.
Cite (Informal):
Can Pretrained Language Models Derive Correct Semantics from Corrupt Subwords under Noise? (Li et al., *SEM 2023)
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PDF:
https://aclanthology.org/2023.starsem-1.15.pdf
Software:
 2023.starsem-1.15.software.zip