Reflect-RL: Two-Player Online RL Fine-Tuning for LMs

Runlong Zhou, Simon Du, Beibin Li


Abstract
As language models (LMs) demonstrate their capabilities in various fields, their application to tasks requiring multi-round interactions has become increasingly popular. These tasks usually have complex dynamics, so supervised fine-tuning (SFT) on a limited offline dataset does not yield good performance. However, only a few works attempted to directly train the LMs within interactive decision-making environments. We aim to create an effective approach to fine-tune LMs with online reinforcement learning (RL) in these environments. We propose Reflect-RL, a two-player system to fine-tune an LM using SFT and online RL, where a frozen reflection model (player) assists the policy model (player). To generate data for the warm-up SFT stage, we use negative example generation to enhance the error-correction ability of the reflection model. Furthermore, we designed single-prompt action enumeration and applied curriculum learning to allow the policy model to learn more efficiently. Empirically, we verify that Reflect-RL outperforms SFT and online RL without reflection. Testing results indicate GPT-2 XL 1.56B fine-tuned with Reflect-RL outperforms larger open-source LMs, such as Mistral 7B. The benchmarks, dataset, and code involved in this work are publicly available: https://github.com/zhourunlong/Reflect-RL.
Anthology ID:
2024.acl-long.56
Volume:
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
August
Year:
2024
Address:
Bangkok, Thailand
Editors:
Lun-Wei Ku, Andre Martins, Vivek Srikumar
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
995–1015
Language:
URL:
https://aclanthology.org/2024.acl-long.56
DOI:
10.18653/v1/2024.acl-long.56
Bibkey:
Cite (ACL):
Runlong Zhou, Simon Du, and Beibin Li. 2024. Reflect-RL: Two-Player Online RL Fine-Tuning for LMs. In Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 995–1015, Bangkok, Thailand. Association for Computational Linguistics.
Cite (Informal):
Reflect-RL: Two-Player Online RL Fine-Tuning for LMs (Zhou et al., ACL 2024)
Copy Citation:
PDF:
https://preview.aclanthology.org/add_acl24_videos/2024.acl-long.56.pdf
Video:
 https://preview.aclanthology.org/add_acl24_videos/2024.acl-long.56.mp4