arXiv Machine Learning

How Far Can You Steer? Behavior-Capability Frontiers in Contrastive Activation Addition

arXiv Computation and Language
Oct 21

RealControlBench: A Benchmark for Interpretability-Informed Fine-Grained Control of LLMs and Agents

RealControlBench is a new benchmark that evaluates fine‑grained steering of large language models and agents across diverse behavioral targets and interaction settings. It extends beyond isolated generation tasks to include complex, execution‑grounded, multi‑turn agent interactions, covering instruction‑following control, tool‑use decision control, reasoning performance, reasoning length, and safety awareness. The benchmark jointly measures target controllability and capability preservation, testing robustness across prompts, domains, and model architectures, and finds that current steering methods are often unreliable in realistic scenarios.

By Xinying Cai, Bin Hu, Mingyu Jin, Qiming Zhang, Yang Ouyang, Bangwei Guo, Minghao Guo, Yutong Yin, Lang Gao, Feijiang Han, Sheldon Yu, Kaiqu Liang, Qingcheng Zeng, Jingcheng Niu, Fan Yang, Wei Cheng, Zhen Xiang, Julian McAuley, Zhaoran Wang
arXiv Machine Learning
Oct 2

When Instructions Retrieve Trajectories: Diagnosing and Mitigating Generalization Failures in VLA Models

The paper investigates a specific failure mode in vision‑language‑action models, termed instruction‑action binding, where models respond to language and vision separately but fail to combine them to select the correct action under counterfactual changes. Through behavioral analyses of fine‑tuned policies, the authors show that failed rollouts often preserve source behavior or switch to other demonstrated tasks, indicating that language is not ignored but mis‑bound. They propose Equivariant Counterfactual Training (ECT), which supplies counterfactual demonstrations and a paired loss to enforce correct action selection, achieving significant performance gains across simulated and real‑world benchmarks.

By Hung-Jen Chen, Yu-Hsun Hou, Yan-Hong Chen, Yan-Fu Chen, Binghua Cai, Min Sun, Chun-Yi Lee
arXiv AI
Sep 28

FLIP: Final Layer Inference-Time Probing for Vision-Language Models

FLIP is a final‑layer inference‑time probe designed to test whether a logit‑facing intervention site in an open‑weight vision‑language model (VLM) supports structured, task‑linked computation rather than generic perturbation. The probe applies elementwise flooring to the final normalized hidden state before logit computation, leaving other model components unchanged. By sweeping intervention strength on a controlled detection/counting task, FLIP identifies three regimes—negligible change, a bounded interior regime with improved detection recall and reduced counting error, and over‑suppression—while a four‑criterion protocol ensures the observed effects are mechanistically interpretable.

By Drandreb Earl O. Juanico, Rowel O. Atienza