Representations of Syntax [MASK] Useful: Effects of Constituency and Dependency Structure in Recursive LSTMs

Michael Lepori, Tal Linzen, R. Thomas McCoy


Abstract
Sequence-based neural networks show significant sensitivity to syntactic structure, but they still perform less well on syntactic tasks than tree-based networks. Such tree-based networks can be provided with a constituency parse, a dependency parse, or both. We evaluate which of these two representational schemes more effectively introduces biases for syntactic structure that increase performance on the subject-verb agreement prediction task. We find that a constituency-based network generalizes more robustly than a dependency-based one, and that combining the two types of structure does not yield further improvement. Finally, we show that the syntactic robustness of sequential models can be substantially improved by fine-tuning on a small amount of constructed data, suggesting that data augmentation is a viable alternative to explicit constituency structure for imparting the syntactic biases that sequential models are lacking.
Anthology ID:
2020.acl-main.303
Volume:
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics
Month:
July
Year:
2020
Address:
Online
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
3306–3316
Language:
URL:
https://aclanthology.org/2020.acl-main.303
DOI:
10.18653/v1/2020.acl-main.303
Bibkey:
Cite (ACL):
Michael Lepori, Tal Linzen, and R. Thomas McCoy. 2020. Representations of Syntax [MASK] Useful: Effects of Constituency and Dependency Structure in Recursive LSTMs. In Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics, pages 3306–3316, Online. Association for Computational Linguistics.
Cite (Informal):
Representations of Syntax [MASK] Useful: Effects of Constituency and Dependency Structure in Recursive LSTMs (Lepori et al., ACL 2020)
Copy Citation:
PDF:
https://aclanthology.org/2020.acl-main.303.pdf
Video:
 http://slideslive.com/38928898
Code
 mlepori1/Representations_Of_Syntax