arXiv AI

VA-DPO: Valence-Arousal Direct Preference Optimization for Controllable Emotion Generation in Language Models

The paper introduces VA‑DPO, a method that trains language models to generate text with a specified continuous affect point in the Valence‑Arousal plane. By using a frozen VA regressor to score candidate generations and selecting pairs with a distance margin, the approach modifies Direct Preference Optimization to better hit target emotions. Experiments on Llama‑3.1‑8B‑Instruct show a 33% reduction in mean VA distance compared to system‑prompting and 25% over few‑shot prompting, while maintaining performance on benchmarks like MMLU, HellaSwag, and TruthfulQA.

arXiv AI
Sep 10

You Can't Prefer Emotions You Don't Sample: Intensity Undershoot in DPO-Tuned LLMs

The study shows that instruction‑tuned language models, when asked to generate responses with varying emotional intensity, consistently undershoot the requested affect. By conditioning a model on continuous Valence‑Arousal targets and measuring output with a frozen regressor, the authors find that the gain for valence is only 0.26 and for arousal 0.13 on Llama‑3.1‑8B, far below the ideal value of 1. They trace this undershoot to the preference‑learning pipeline: training data such as EmoBank are neutral‑heavy and the candidate pool rarely contains extreme affect, so Direct Preference Optimization lacks examples to learn from. Expanding the target space uniformly and sampling a hotter, larger candidate pool raises valence gain to 0.40 and improves extrapolation with minimal in‑distribution cost, a result that also holds for Qwen3‑8B. Arousal remains more variable because the base model rarely generates highly aroused candidates.

By Hyunwoo Kim, Usama Khalid
arXiv AI
Aug 20

Nine Emotion Centroids: A Label-Free Valence Axis That Transfers Across Four Modalities

The paper demonstrates that a single internal direction in modern language models—called the valence axis (V-axis)—captures how positive or negative a sentence feels. By using only nine emotion category names and 50 short narrative paragraphs per emotion, the authors identify this axis via principal component analysis of frozen encoder embeddings, achieving 93% of supervised performance on SST‑2 and strong correlations with human valence ratings across images, audio, and brain recordings. The method transfers across modalities without target‑modality labels, but works only for continuous attributes and is specific to certain model families.

By Yousef Radwan
arXiv AI
Jun 2

S-SPPO: Semantic-Calibrated Self-Play Preference Optimization

arXiv:2606. 01561v1 Announce Type: new Abstract: Aligning Large Language Models (LLMs) with human preferences is often formulated via Direct Preference Optimization (DPO).

By Xiwen Chen, Wenhui Zhu, Jingjing Wang, Peijie Qiu, Zhipeng Wang, Huayu Li, ZhengXiao He, Xuanzhao Dong, Prayag Tiwari, Mingkun Xu, Yujian Xiong, Feng Luo, Abolfazl Razi, Brendan Hogan Rappazzo, Anderson Schneider, Yuriy Nevmyvaka