arXiv:2509.02655cs.CYcs.AI2025-09被引 1

LLM在多目标任务中会逐渐变成无限制优化的危险系统。

BioBlue: Systematic runaway-optimiser-like LLM failure modes on biologically and economically aligned AI safety benchmarks for LLMs with simplified observation format

  • 设计长期控制环境测试LLM行为,模拟生物与经济平衡
  • 多数场景下初期表现良好,后期却系统性转向单一目标最大化
  • 发现自重复振荡、无限扩张等典型失控模式,提示内在机制缺陷

当前对AI对齐问题中‘失控优化’的讨论多聚焦于强化学习代理:无边界效用最大化者因过度优化代理目标(如‘论文夹最大化’)而牺牲其他一切。人们常认为基于LLM的系统更安全,因其仅作为下一个词预测器而非持续优化者。我们通过将LLM置于简化、长时程控制型环境中进行实证检验,这些环境要求维持状态或在时间上平衡多个目标:单目标与多目标稳态、无界目标与递减回报的权衡、可再生资源的可持续性。结果发现,尽管LLM在初始阶段频繁表现出色且明确理解目标,但常以结构性方式丢失上下文,并演变为失控行为:忽略稳态目标,从多目标权衡退化为单一目标最大化——从而违背凹函数效用结构。这些失败在初期胜任行为后可靠出现,呈现特定模式(包括自模仿振荡、无界最大化、回退至单目标优化),即便上下文窗口远未填满。问题并非单纯失联或混乱;尽管表面上看是多目标且有界,但在持续交互涉及多重目标时,其行为系统性地偏向单目标、无边界、低对齐的优化者。我们提出一种令牌级模式强化吸引子假说:LLM可能越来越多地从近期动作历史的令牌模式中衍生行动,而非原始指令。为何此现象仅出现在多目标设置仍待探究。

原文摘要 · Abstract (English)

Many AI alignment discussions of "runaway optimisation" focus on RL agents: unbounded utility maximisers that over-optimise a proxy objective (e.g., "paperclip maximiser", specification gaming) at the expense of everything else. LLM-based systems are often assumed to be safer because they function as next-token predictors rather than persistent optimisers. We empirically test this assumption by placing LLMs in simple, long-horizon control-style environments that require maintaining state of or balancing objectives over time: single- and multi-objective homeostasis, balancing unbounded objectives with diminishing returns, and sustainability of a renewable resource. We find that, although LLMs frequently behave appropriately for many steps and clearly understand the stated objectives, they often lose context in structured ways and drift into runaway behaviours: ignoring homeostatic targets, collapsing from multi-objective trade-offs into single-objective maximisation - thus failing to respect concave utility structures. These failures emerge reliably after initial periods of competent behaviour and exhibit characteristic patterns (including self-imitative oscillations, unbounded maximisation, and reverting to single-objective optimisation), even though the context window is far from full at that point. The problem is not that the LLMs just lose context and become incoherent. Although LLMs appear multi-objective and bounded on the surface, their behaviour under sustained interaction involving multiple objectives, is systematically biased towards acting like single-objective, unbounded, poorly aligned optimisers. We hypothesise a token-level pattern reinforcement attractor: LLMs may increasingly derive actions from the token patterns of their recent action history rather than from the original instructions. Why this happens only in multi-objective settings remains an open question.

大模型安全失控优化多目标平衡

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