RewardsOfSum: Exploring Reinforcement Learning Rewards for Summarisation

Jacob Parnell, Inigo Jauregi Unanue, Massimo Piccardi


Abstract
To date, most abstractive summarisation models have relied on variants of the negative log-likelihood (NLL) as their training objective. In some cases, reinforcement learning has been added to train the models with an objective that is closer to their evaluation measures (e.g. ROUGE). However, the reward function to be used within the reinforcement learning approach can play a key role for performance and is still partially unexplored. For this reason, in this paper, we propose two reward functions for the task of abstractive summarisation: the first function, referred to as RwB-Hinge, dynamically selects the samples for the gradient update. The second function, nicknamed RISK, leverages a small pool of strong candidates to inform the reward. In the experiments, we probe the proposed approach by fine-tuning an NLL pre-trained model over nine summarisation datasets of diverse size and nature. The experimental results show a consistent improvement over the negative log-likelihood baselines.
Anthology ID:
2021.spnlp-1.1
Volume:
Proceedings of the 5th Workshop on Structured Prediction for NLP (SPNLP 2021)
Month:
August
Year:
2021
Address:
Online
Venues:
ACL | IJCNLP | spnlp
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1–11
Language:
URL:
https://aclanthology.org/2021.spnlp-1.1
DOI:
10.18653/v1/2021.spnlp-1.1
Bibkey:
Cite (ACL):
Jacob Parnell, Inigo Jauregi Unanue, and Massimo Piccardi. 2021. RewardsOfSum: Exploring Reinforcement Learning Rewards for Summarisation. In Proceedings of the 5th Workshop on Structured Prediction for NLP (SPNLP 2021), pages 1–11, Online. Association for Computational Linguistics.
Cite (Informal):
RewardsOfSum: Exploring Reinforcement Learning Rewards for Summarisation (Parnell et al., spnlp 2021)
Copy Citation:
PDF:
https://aclanthology.org/2021.spnlp-1.1.pdf
Data
NEWSROOM