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Zeen Song

6 accepted papers

2026

Causal Reward Adjustment: Mitigating Reward Hacking in External Reasoning via Backdoor Correction

AAAI 2026technical

External reasoning systems combine language models with process reward models (PRMs) to select high-quality reasoning paths for complex tasks such as mathematical problem solving. However, these systems are prone to reward hacking, where high-scoring but logically incorrect paths are assigned high s

Cited by 0SourcePDFScholar
2026

Group Causal Policy Optimization for Post-Training Large Language Models

AAAI 2026technical

Recent advances in large language models (LLMs) have broadened their applicability across diverse tasks, yet specialized domains still require targeted post-training. Among existing methods, Group Relative Policy Optimization (GRPO) stands out for its efficiency, leveraging groupwise relative reward

Cited by 0SourcePDFScholar
2025

Learning Invariant Causal Mechanism from Vision-Language Models

ICML 2025poster

Contrastive Language-Image Pretraining (CLIP) has achieved remarkable success, but its performance can degrade when fine-tuned in out-of-distribution (OOD) scenarios. We model the prediction process using a Structural Causal Model (SCM) and show that the causal mechanism involving both invariant and…

Cited by 0SourcePDFScholar
2025

Learning to Think: Information-Theoretic Reinforcement Fine-Tuning for LLMs

NeurIPS 2025poster

Large language models (LLMs) excel at complex tasks thanks to advances in their reasoning abilities. However, existing methods overlook the trade-off between reasoning effectiveness and efficiency, often encouraging unnecessarily long reasoning chains and wasting tokens. To address this, we propose…

Cited by 0SourceScholar
2025

On the Out-of-Distribution Generalization of Self-Supervised Learning

ICML 2025poster

In this paper, we focus on the out-of-distribution (OOD) generalization of self-supervised learning (SSL). By analyzing the mini-batch construction during the SSL training phase, we first give one plausible explanation for SSL having OOD generalization. Then, from the perspective of data generation…

2024

Hacking Task Confounder in Meta-Learning

IJCAI 2024poster

Meta-learning enables rapid generalization to new tasks by learning knowledge from various tasks. It is intuitively assumed that as the training progresses, a model will acquire richer knowledge, leading to better generalization performance. However, our experiments reveal an unexpected result: ther…