arXiv AI

Which Objectives Need a Dial? Predicting Objective Conflict and Covering Trade-offs in Steerable Pluralistic Alignment

The paper investigates how to create steerable AI models that can balance multiple, sometimes conflicting objectives, a necessity for pluralistic alignment. Using Multi-Objective Direct Preference Optimization (MODPO), the authors examine when a single model can improve two objectives simultaneously and how to cover many trade‑offs without training separate models. They find that two pre‑training measurements predict objective alignment for human‑annotated data but not for AI‑annotated data, and that selecting the nearest trained model or merging parameters can broaden trade‑off coverage, though neither approach consistently matches direct training.

arXiv AI
4d ago

PADM\'E: Preference Alignment Data Synthesis for Meta-Evaluation of LM Agent Evaluators

PADM'E is a method for synthesizing preference‑aligned data to meta‑evaluate language‑model (LM) evaluators of agentic behaviors. It reframes meta‑evaluation as a preference judgment problem, generating criterion‑based data with small LMs and no human involvement. In a prototype, PADM'E produced 1,000 samples across four domains and three criteria, and human validation showed agreement with human judgment rising from 73% to 85% compared to a naive baseline.

By Cheng Chang, Yining Mao, Peng Qi
arXiv Computation and Language
Sep 3

GroupDPO: Memory-Efficient Group-Wise Direct Preference Optimization

GroupDPO introduces a memory‑efficient approach to group‑wise direct preference optimization for aligning large language models. By using first‑order linearization with per‑response coefficients, the method decouples samples during backpropagation, dramatically reducing peak memory usage and enabling scalable training with larger groups. Experiments in both offline and online settings show that leveraging multiple responses consistently outperforms single‑pair training, and adding a negative log‑likelihood term on positive responses is essential for performance gains and training stability.

By Jixuan Leng, Si Si, Hsiang-Fu Yu, Vinod Raman, Inderjit S. Dhillon
arXiv AI
Aug 26

Preference Data Selection for Mitigating the Alignment Tax in Large Language Models

The paper introduces BALIGN, a balanced data selection strategy designed to reduce catastrophic forgetting—referred to as the alignment tax—in large language models during preference-based alignment. By analyzing preference optimization gradients, the authors identify three data-centric features that influence parameter drift: the reference model's log-probability margin, token length differences between chosen and rejected responses, and TF‑IDF similarity to general capability corpora. BALIGN aggregates these features into a composite risk score to filter out high-risk preference samples, thereby preserving foundational capabilities while maintaining alignment gains with minimal computational overhead.

By Minsu Kim, Jianxun Lian, Xing Xie, Steven Euijong Whang
arXiv Machine Learning
Aug 20

To Go Far, Go Together: Diverse Preferences Induce a Curriculum for Reward Optimization

The paper introduces CurriPO, a tree‑structured curriculum that automatically adapts to diverse user reward models in AI alignment tasks. By exploiting the natural hierarchy between easy‑ and hard‑to‑optimize reward models, CurriPO covers a broad user population in a single traversal, reusing previously incorporated reward models. Experiments on personalized continuous control show that CurriPO improves population satisfaction by 1.2–2.1× over the strongest baseline while cutting training time and better serving users traditionally underserved by conventional optimization.

By Taehyung Kim, Jongeun Choi