Evaluating the Robustness of Discrete Prompts

Yoichi Ishibashi, Danushka Bollegala, Katsuhito Sudoh, Satoshi Nakamura


Abstract
Discrete prompts have been used for fine-tuning Pre-trained Language Models for diverse NLP tasks. In particular, automatic methods that generate discrete prompts from a small set of training instances have reported superior performance. However, a closer look at the learnt prompts reveals that they contain noisy and counter-intuitive lexical constructs that would not be encountered in manually-written prompts. This raises an important yet understudied question regarding the robustness of automatically learnt discrete prompts when used in downstream tasks. To address this question, we conduct a systematic study of the robustness of discrete prompts by applying carefully designed perturbations into an application using AutoPrompt and then measure their performance in two Natural Language Inference (NLI) datasets. Our experimental results show that although the discrete prompt-based method remains relatively robust against perturbations to NLI inputs, they are highly sensitive to other types of perturbations such as shuffling and deletion of prompt tokens. Moreover, they generalize poorly across different NLI datasets. We hope our findings will inspire future work on robust discrete prompt learning.
Anthology ID:
2023.eacl-main.174
Volume:
Proceedings of the 17th Conference of the European Chapter of the Association for Computational Linguistics
Month:
May
Year:
2023
Address:
Dubrovnik, Croatia
Editors:
Andreas Vlachos, Isabelle Augenstein
Venue:
EACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
2373–2384
Language:
URL:
https://aclanthology.org/2023.eacl-main.174
DOI:
10.18653/v1/2023.eacl-main.174
Bibkey:
Cite (ACL):
Yoichi Ishibashi, Danushka Bollegala, Katsuhito Sudoh, and Satoshi Nakamura. 2023. Evaluating the Robustness of Discrete Prompts. In Proceedings of the 17th Conference of the European Chapter of the Association for Computational Linguistics, pages 2373–2384, Dubrovnik, Croatia. Association for Computational Linguistics.
Cite (Informal):
Evaluating the Robustness of Discrete Prompts (Ishibashi et al., EACL 2023)
Copy Citation:
PDF:
https://aclanthology.org/2023.eacl-main.174.pdf
Video:
 https://aclanthology.org/2023.eacl-main.174.mp4