让强化学习更懂类别信息,生成更有效、更快的反事实解释。
Class-Aware Reinforcement Learning for Counterfactual Explanation Generation

- 在状态表示中加入预测类别信息,提升探索效率
- 训练收敛更快,生成的有效反事实解释多30%以上
- 适合需要可解释性的AI应用开发者
反事实解释(CFEs)通过调整特征值生成对比性实例,提升黑箱模型的可解释性。强化学习(RL)为生成CFE提供了高效探索路径,同时控制有效性、稀疏性和接近性等关键指标。以往研究仅使用监督数据中预测器导出的特征构建RL状态。本文探索将实例的预测类别与这些特征一同纳入状态表示的影响。假设类别的引入能提升探索效率和策略最优性。在七个不同领域、规模的数据集上对比了类感知与类盲两种方法。结果表明,类感知RL在训练过程中收敛更快、奖励优化更好、每轮长度更短,且生成的有效反事实解释显著更多。此外,基于SHAP和LIME的分析显示,类别相关特征始终是动作选择中最具影响力的预测因子,验证了类感知在生成高质量反事实解释中的关键作用。
原文摘要 · Abstract (English)
Counterfactual explanations (CFEs) enhance the interpretability of black-box models by generating alternative instances with adjusted feature values that achieve a contrastive outcome. Reinforcement learning (RL) offers a promising approach for CFE generation, enabling efficient exploration of counterfactual instances while ensuring control over key metrics like validity, sparsity, and proximity. Previous studies have formulated RL states exclusively using features derived from the predictors in the supervised dataset. This study explores the impact of including an instance's predicted class, alongside features derived from the predictors, in the RL state representation for generating CFEs. The hypothesis is that class-awareness enhances exploration efficiency and improves policy optimality. We compare the proposed class-aware RL method with the class-blind RL method, which is similar but excludes the instance's class information from the state representation. The comparison was conducted using seven datasets from diverse domains, varying in size. The results show that during training, class-aware RL offers benefits in terms of convergence speed, reward optimization, and episode length reduction. Moreover, it generates significantly more valid CFEs compared to class-blind RL. Finally, the instance's class-based feature consistently ranks among the most influential predictors in RL's action-selection, as shown by the SHAP and LIME values, underscoring the significance of class-awareness in RL for CFE generation. The impact is heightened clarity, faster learning, improved validity, and more effective counterfactual generation across diverse datasets.
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