Reward Engineering for Generating Semi-structured Explanation

Jiuzhou Han, Wray Buntine, Ehsan Shareghi


Abstract
Semi-structured explanation depicts the implicit process of a reasoner with an explicit representation. This explanation highlights how available information in a specific query is utilised and supplemented with information a reasoner produces from its internal weights towards generating an answer. Despite the recent improvements in generative capabilities of language models, producing structured explanations to verify a model’s true reasoning capabilities remains a challenge. This issue is particularly pronounced for not-so-large LMs (e.g., FLAN-T5-XXL). In this work, we first underscore the limitations of supervised fine-tuning (SFT) in tackling this challenge, and then introduce a carefully crafted reward engineering method in reinforcement learning (RL) to better address this problem. We investigate multiple reward aggregation methods and provide a detailed discussion which sheds light on the promising potential of RL for future research. Our proposed method on two semi-structured explanation generation benchmarks (ExplaGraph and COPA-SSE) achieves new state-of-the-art results.
Anthology ID:
2024.findings-eacl.41
Volume:
Findings of the Association for Computational Linguistics: EACL 2024
Month:
March
Year:
2024
Address:
St. Julian’s, Malta
Editors:
Yvette Graham, Matthew Purver
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
589–602
Language:
URL:
https://aclanthology.org/2024.findings-eacl.41
DOI:
Bibkey:
Cite (ACL):
Jiuzhou Han, Wray Buntine, and Ehsan Shareghi. 2024. Reward Engineering for Generating Semi-structured Explanation. In Findings of the Association for Computational Linguistics: EACL 2024, pages 589–602, St. Julian’s, Malta. Association for Computational Linguistics.
Cite (Informal):
Reward Engineering for Generating Semi-structured Explanation (Han et al., Findings 2024)
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PDF:
https://aclanthology.org/2024.findings-eacl.41.pdf