arXiv:2602.21424cs.LGcs.AI2026-02

研究强化学习中策略变换对认知行为结构的破坏性影响。

On the Structural Non-Preservation of Epistemic Behaviour under Policy Transformation

  • 定义行为依赖性,量化策略在不同内部信息下的动作变化
  • 凸组合策略时行为距离收缩,且优化可进一步降低距离
  • 适用于分析策略迁移、隐状态变化场景下的行为稳定性

部分可观测强化学习中,智能体常基于内部积累的信息(如记忆或隐状态)决定动作。本文将此类信息依赖的交互模式形式化为行为依赖性:在固定观测下,动作选择随内部信息的变化。由此引出与探测器相关的ε-行为等价和策略内行为距离,用于度量对探测器的敏感性。本文建立三个结构性结论:第一,具有非平凡行为依赖性的策略集合在凸组合下不封闭;第二,行为距离在凸组合下收缩;第三,当主导梯度方向与最速收缩方向一致时,偏斜混合目标的梯度上升可减少行为距离。最小化老虎机与部分可观测网格世界实验验证了这些机制。在实验中,凸组合及持续优化下行为距离下降,且该下降先于隐状态先验漂移导致的性能退化。结果揭示了在常见策略变换下,探测器依赖的行为分离性可能被破坏的结构性条件。

原文摘要 · Abstract (English)

Reinforcement learning (RL) agents under partial observability often condition actions on internally accumulated information such as memory or inferred latent context. We formalise such information-conditioned interaction patterns as behavioural dependency: variation in action selection with respect to internal information under fixed observations. This induces a probe-relative notion of $ε$-behavioural equivalence and a within-policy behavioural distance that quantifies probe sensitivity. We establish three structural results. First, the set of policies exhibiting non-trivial behavioural dependency is not closed under convex aggregation. Second, behavioural distance contracts under convex combination. Third, we prove a sufficient local condition under which gradient ascent on a skewed mixture objective decreases behavioural distance when a dominant-mode gradient aligns with the direction of steepest contraction. Minimal bandit and partially observable gridworld experiments provide controlled witnesses of these mechanisms. In the examined settings, behavioural distance decreases under convex aggregation and under continued optimisation with skewed latent priors, and in these experiments it precedes degradation under latent prior shift. These results identify structural conditions under which probe-conditioned behavioural separation is not preserved under common policy transformations.

强化学习行为分析策略变换

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