通过概念层让大模型既可解释又能动态干预。
Concept Layers: Enhancing Interpretability and Intervenability via LLM Conceptualization
- 在模型中插入概念层,将内部向量映射到可解释空间。
- 无需人工选概念,自动从知识图谱搜索适用概念集。
- 支持实时调整模型行为,如消除推理中的偏见。
大语言模型的不透明性促使研究者探索提升其可解释性的方法,以往多采用事后分析手段。近期的原生方法如概念瓶颈模型(CBMs)虽兼顾可解释性与可干预性,但依赖标注的概念数据集,且需大幅修改架构,难以融入现有系统。本文提出一种新方法——概念层(Concept Layers, CLs),通过将模型内部向量投影至概念化的可解释空间,并重构反馈回模型,实现对已有模型的可解释性增强。同时,我们通过算法自动从本体库中搜索任务特定或通用的概念集合,避免人工设定。在多个任务上评估表明,该方法在保持原始模型性能和一致性的同时,支持有效干预。我们还展示了一个可干预接口的原型,用户可在推理过程中动态调节模型行为,例如减轻偏见。
原文摘要 · Abstract (English)
The opaque nature of Large Language Models (LLMs) has led to significant research efforts aimed at enhancing their interpretability, primarily through post-hoc methods. More recent in-hoc approaches, such as Concept Bottleneck Models (CBMs), offer both interpretability and intervenability by incorporating explicit concept representations. However, these methods suffer from key limitations, including reliance on labeled concept datasets and significant architectural modifications that challenges re-integration into existing system pipelines. In this work, we introduce a new methodology for incorporating interpretability and intervenability into an existing model by integrating Concept Layers (CLs) into its architecture. Our approach projects the model's internal vector representations into a conceptual, explainable vector space before reconstructing and feeding them back into the model. Furthermore, we eliminate the need for a human-selected concept set by algorithmically searching an ontology for a set of concepts that can be either task-specific or task-agnostic. We evaluate CLs across multiple tasks, demonstrating that they maintain the original model's performance and agreement while enabling meaningful interventions. Additionally, we present a proof of concept showcasing an intervenability interface, allowing users to adjust model behavior dynamically, such as mitigating biases during inference.
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