Debiasing Pre-trained Contextualised Embeddings

Masahiro Kaneko, Danushka Bollegala


Abstract
In comparison to the numerous debiasing methods proposed for the static non-contextualised word embeddings, the discriminative biases in contextualised embeddings have received relatively little attention. We propose a fine-tuning method that can be applied at token- or sentence-levels to debias pre-trained contextualised embeddings. Our proposed method can be applied to any pre-trained contextualised embedding model, without requiring to retrain those models. Using gender bias as an illustrative example, we then conduct a systematic study using several state-of-the-art (SoTA) contextualised representations on multiple benchmark datasets to evaluate the level of biases encoded in different contextualised embeddings before and after debiasing using the proposed method. We find that applying token-level debiasing for all tokens and across all layers of a contextualised embedding model produces the best performance. Interestingly, we observe that there is a trade-off between creating an accurate vs. unbiased contextualised embedding model, and different contextualised embedding models respond differently to this trade-off.
Anthology ID:
2021.eacl-main.107
Volume:
Proceedings of the 16th Conference of the European Chapter of the Association for Computational Linguistics: Main Volume
Month:
April
Year:
2021
Address:
Online
Venue:
EACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1256–1266
Language:
URL:
https://aclanthology.org/2021.eacl-main.107
DOI:
10.18653/v1/2021.eacl-main.107
Bibkey:
Copy Citation:
PDF:
https://aclanthology.org/2021.eacl-main.107.pdf
Code
 kanekomasahiro/context-debias
Data
GLUEMRPCSST