Probing for the Usage of Grammatical Number
Karim Lasri, Tiago Pimentel, Alessandro Lenci, Thierry Poibeau, Ryan Cotterell
Abstract
A central quest of probing is to uncover how pre-trained models encode a linguistic property within their representations. An encoding, however, might be spurious—i.e., the model might not rely on it when making predictions. In this paper, we try to find an encoding that the model actually uses, introducing a usage-based probing setup. We first choose a behavioral task which cannot be solved without using the linguistic property. Then, we attempt to remove the property by intervening on the model’s representations. We contend that, if an encoding is used by the model, its removal should harm the performance on the chosen behavioral task. As a case study, we focus on how BERT encodes grammatical number, and on how it uses this encoding to solve the number agreement task. Experimentally, we find that BERT relies on a linear encoding of grammatical number to produce the correct behavioral output. We also find that BERT uses a separate encoding of grammatical number for nouns and verbs. Finally, we identify in which layers information about grammatical number is transferred from a noun to its head verb.- Anthology ID:
- 2022.acl-long.603
- Original:
- 2022.acl-long.603v1
- Version 2:
- 2022.acl-long.603v2
- Volume:
- Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
- Month:
- May
- Year:
- 2022
- Address:
- Dublin, Ireland
- Venue:
- ACL
- SIG:
- Publisher:
- Association for Computational Linguistics
- Note:
- Pages:
- 8818–8831
- Language:
- URL:
- https://aclanthology.org/2022.acl-long.603
- DOI:
- 10.18653/v1/2022.acl-long.603
- Cite (ACL):
- Karim Lasri, Tiago Pimentel, Alessandro Lenci, Thierry Poibeau, and Ryan Cotterell. 2022. Probing for the Usage of Grammatical Number. In Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 8818–8831, Dublin, Ireland. Association for Computational Linguistics.
- Cite (Informal):
- Probing for the Usage of Grammatical Number (Lasri et al., ACL 2022)
- PDF:
- https://preview.aclanthology.org/remove-xml-comments/2022.acl-long.603.pdf