V-VAE: A Variational Auto Encoding Framework Towards Fine-Grained Control over Human-Like Chat

Qi Lin, Weikai Xu, Lisi Chen, Bin Dai


Abstract
With the continued proliferation of Large Language Model (LLM) based chatbots, there is a growing demand for generating responses that are not only linguistically fluent but also consistently aligned with persona-specific traits in conversations. However, existing role-play and persona-based chat approaches rely heavily on static role descriptions, coarse-grained signal space, and low-quality synthetic data, which fail to capture dynamic fine-grained details in human-like chat. Human-like chat requires modeling subtle latent traits, such as emotional tone, situational awareness, and evolving personality, which are difficult to predefine and cannot be easily learned from synthetic or distillation-based data. To address these limitations, we propose a Verbal Variational Auto-Encoding (V-VAE) framework, containing a variational auto-encoding module and fine-grained control space which dynamically adapts dialogue behaviour based on fine-grained, interpretable latent variables across talking style, interaction patterns, and personal attributes. We also construct a high-quality dataset, HumanChatData, and benchmark HumanChatBench to address the scarcity of high-quality data in the human-like domain. Experiments show that LLMs based on V-VAE consistently outperform standard baselines on HumanChatBench and DialogBench, which further demonstrates the effectiveness of V-VAE and HumanChatData.
Anthology ID:
2025.emnlp-main.1508
Volume:
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2025
Address:
Suzhou, China
Editors:
Christos Christodoulopoulos, Tanmoy Chakraborty, Carolyn Rose, Violet Peng
Venue:
EMNLP
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Publisher:
Association for Computational Linguistics
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Pages:
29681–29694
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URL:
https://preview.aclanthology.org/ingest-emnlp/2025.emnlp-main.1508/
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Cite (ACL):
Qi Lin, Weikai Xu, Lisi Chen, and Bin Dai. 2025. V-VAE: A Variational Auto Encoding Framework Towards Fine-Grained Control over Human-Like Chat. In Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing, pages 29681–29694, Suzhou, China. Association for Computational Linguistics.
Cite (Informal):
V-VAE: A Variational Auto Encoding Framework Towards Fine-Grained Control over Human-Like Chat (Lin et al., EMNLP 2025)
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