From Homogeneity to Diversity: Self-Refined GRPO for Controllable Creative Writing

Minna Peng, Wei Tan, Zeyu Wang, Yongquan Hu, Ruizhi Huang, Yang Jie


Abstract
Controllable creative writing is a text generation task that requires both high generation quality and diverse outputs. However, existing methods often improve one aspect at the expense of the other. To address this challenge, we propose SERGE, a reinforcement learning (RL) framework that introduces a diversity-guided self-refinement mechanism, where the policy itself refines low-diversity candidate texts, and employs policy shaping to amplify the gradient contributions of samples with both high generation quality and diversity. We also propose a fine-grained reward modeling framework to provide reliable quality reward signals to support RL optimization. Experiments on the short-form video copywriting generation task show that SERGE outperforms the base model and conventional diversity-enhancement strategies on both diversity metrics (DisNGram, PairBLEU, CosSim) and generation quality, effectively alleviating the "diversity collapse” issue in RL. Our code is available at: https://github.com/peng-mn/SERGE.
Anthology ID:
2026.findings-emnlp.972
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
20555–20571
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.972/
DOI:
Bibkey:
Cite (ACL):
Minna Peng, Wei Tan, Zeyu Wang, Yongquan Hu, Ruizhi Huang, and Yang Jie. 2026. From Homogeneity to Diversity: Self-Refined GRPO for Controllable Creative Writing. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 20555–20571, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
From Homogeneity to Diversity: Self-Refined GRPO for Controllable Creative Writing (Peng et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.972.pdf