arXiv:2604.08169cs.AI2026-04被引 2

通过激活调控修复大模型的对齐问题,不牺牲生成能力。

Activation Steering for Aligned Open-ended Generation without Sacrificing Coherence

  • 用激活空间中的线性结构进行选择性干预,精准修正错误行为。
  • 在欺骗和否定两种威胁场景下,均显著恢复模型对齐性。
  • 方法轻量高效,可泛化到未见过的对抗场景,适合安全增强应用。

大模型的对齐性比普遍认为的更脆弱:对抗提示、良性微调、涌现式错位及目标误泛化均可导致失准。近期证据表明,部分错位行为在激活空间中呈线性结构,可通过激活调控实现可操作的运行时防御。本文实现三种方法:固定系数施加(SwFC),以及两种新颖的投影感知方法——指向目标投影(StTP)和指向镜像投影(StMP),利用逻辑回归决策边界仅对低于阈值的词元激活进行干预。在两个架构(Llama-3.3-70B-Instruct 和 Qwen3.6-27B)上评估两种威胁模型(欺骗与否定),以恶意系统提示作为错位代理。所有方法均显著恢复对齐性;其中 StTP 与 StMP 在保持通用能力(MMLU、MT-Bench、AlpacaEval)方面优于均匀施加。此外,单一从对齐模型提取的诚实方向,能显著提升 MASK 基准得分,抑制多智能体环境(Among Us)中的欺骗行为,使 AuditBench 的隐藏行为发现率翻倍,并恢复因涌现而错位的模型诚实性。

原文摘要 · Abstract (English)

Alignment in LLMs is more brittle than commonly assumed: misalignment can be induced by adversarial prompts, benign fine-tuning, emergent misalignment, and goal misgeneralization. Recent evidence suggests that some misalignment behaviors are encoded as linear structure in activation space, making it tractable via activation steering, which could be used as a lightweight runtime defense. We implement three methods: Steer-With-Fixed-Coefficient (SwFC), which applies uniform additive steering, and two novel projection-aware methods, Steer-to-Target-Projection (StTP) and Steer-to-Mirror-Projection (StMP), that use a logistic regression decision boundary to selectively intervene only on tokens whose activations fall below the threshold. We evaluate these methods on two threat models, dishonesty and dismissiveness, using malicious system prompts as a controlled proxy for misalignment. We conduct our experiments on two architectures (Llama-3.3-70B-Instruct and Qwen3.6-27B). All methods substantially recover alignment. StTP and StMP preserve general capabilities (MMLU, MT-Bench, AlpacaEval) better than uniform steering. Finally, we show that our honesty steering generalizes to out-of-distribution scenarios: a single honesty direction extracted from the aligned model significantly raises scores on the MASK benchmark, suppresses deception in multi-agent settings (Among Us), doubles the hidden-behavior discovery rate on AuditBench, and restores honesty in an emergently misaligned model.

大模型对齐激活调控安全性

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