Word Order Does Matter and Shuffled Language Models Know It

Mostafa Abdou, Vinit Ravishankar, Artur Kulmizev, Anders Søgaard


Abstract
Recent studies have shown that language models pretrained and/or fine-tuned on randomly permuted sentences exhibit competitive performance on GLUE, putting into question the importance of word order information. Somewhat counter-intuitively, some of these studies also report that position embeddings appear to be crucial for models’ good performance with shuffled text. We probe these language models for word order information and investigate what position embeddings learned from shuffled text encode, showing that these models retain a notion of word order information. We show this is in part due to a subtlety in how shuffling is implemented in previous work – before rather than after subword segmentation. Surprisingly, we find even Language models trained on text shuffled after subword segmentation retain some semblance of information about word order because of the statistical dependencies between sentence length and unigram probabilities. Finally, we show that beyond GLUE, a variety of language understanding tasks do require word order information, often to an extent that cannot be learned through fine-tuning.
Anthology ID:
2022.acl-long.476
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:
6907–6919
Language:
URL:
https://aclanthology.org/2022.acl-long.476
DOI:
10.18653/v1/2022.acl-long.476
Bibkey:
Cite (ACL):
Mostafa Abdou, Vinit Ravishankar, Artur Kulmizev, and Anders Søgaard. 2022. Word Order Does Matter and Shuffled Language Models Know It. In Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 6907–6919, Dublin, Ireland. Association for Computational Linguistics.
Cite (Informal):
Word Order Does Matter and Shuffled Language Models Know It (Abdou et al., ACL 2022)
Copy Citation:
PDF:
https://aclanthology.org/2022.acl-long.476.pdf
Data
BookCorpusBoolQCOPAGLUEPAWSReCoRDSuperGLUEWinoGrande