发表机构
Université Libre de Bruxelles; Vrije Universiteit Brussel; FARI Institute; ELLIS Alicante; Center for Human-Compatible AI, UC Berkeley（布鲁塞尔自由大学; 布鲁塞尔自由大学; FARI研究所; ELLIS阿利坎特; 加州大学伯克利分校人类兼容人工智能中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过两个社会困境博弈实验，发现大语言模型的默认遵循行为受界面措辞和行动空间结构显著影响，提示词框架是主导因素。
AI 中文摘要
大语言模型越来越多地被部署为代表用户做出或推荐决策的智能体，通常通过预先填充建议值或默认选项的界面进行操作。模型是将此类默认值视为仅提供信息，还是视为系统性地改变其选择的建议，目前尚不清楚。我们在两个一次性社会困境中研究默认遵循行为：一个公共资源（CPR）提取博弈和一个阈值公共物品（TPG）贡献博弈。我们测量了默认值如何相对于无默认基线改变每个模型的选择分布，涵盖不同的默认值、措辞和行动空间粒度。我们发现，预填充的默认值在两个博弈中都将概率质量拉向默认值，但幅度强烈依赖于措辞：同一模型在一种表述下可能表现出高拉动，而在另一种表述下则几乎为零。许可式措辞在两个博弈中都降低了默认拉动，在CPR中比在TPG中更明显。默认拉动在粗粒度行动空间中较弱，且冲突默认值比一致默认值吸引更多概率质量。这些结果表明，默认遵循行为取决于模型、界面措辞和可用选择的结构。对于智能体系统，在不控制周围选择架构的情况下评估模型行为，可能会遗漏行为变异的一个重要来源。
英文摘要
Large language models are increasingly deployed as agents that make or recommend decisions on behalf of users, often operating through interfaces that pre-fill suggested values or default options. Whether models treat such defaults as merely informational or as suggestions that systematically alter their choices remains unclear. We study default deference in two one-shot social dilemmas: a common-pool resource (CPR) extraction game and a threshold public-good (TPG) contribution game. We measure how defaults shift each model's choice distribution relative to its no-default baseline, across default values, wordings, and action-space granularities. We find that pre-filled defaults pull probability mass on the default value in both games, but the magnitude depends strongly on wording: the same model can show high pull under one formulation and near-zero pull under another. Permission-style wording reduces default pull in both games, more strongly in CPR than in TPG. Default pull is weaker in coarse action spaces, and conflict defaults attract more mass than agreement ones. These results indicate that default deference depends on the model, the wording of the interface, and the structure of available choices. For agentic systems, evaluating model behaviour without controlling the surrounding choice architecture can miss an important source of behavioural variation.
