Mitigating Information Loss in Tree-Based Reinforcement Learning via Direct Optimization
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Abstract (arXiv)
Reinforcement learning (RL) has seen significant success across various domains, but its adoption is often limited by the black-box nature of neural network policies, making them difficult to interpret. In contrast, symbolic policies allow representing decision-making strategies in a compact and interpretable way. However, learning symbolic policies directly within on-policy methods remains challenging. In this paper, we introduce SYMPOL, a novel method for SYMbolic tree-based on-POLicy RL. SYMPOL employs a tree-based model integrated with a policy gradient method, enabling the agent to learn and adapt its actions while maintaining a high level of interpretability. We evaluate SYMPOL on a set of benchmark RL tasks, demonstrating its superiority over alternative tree-based RL approaches in terms of performance and interpretability. Unlike existing methods, it enables gradient-based, end-to-end learning of interpretable, axis-aligned decision trees within standard on-policy RL algorithms. Therefore, SYMPOL can become the foundation for a new class of interpretable RL based on decision trees. Our implementation is available under: https://github.com/s-marton/sympol
Key facts. Cited by 5 papers in the map (data through 7 Oct 2026). Builds on 39 of its 59 references that are in the map. First posted on arXiv 16 Aug 2024.
Builds on
39 of 59 references.
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27 more
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Citing papers per year: 2025: 3; 2026: 2.
5 papers.
- 2025Evaluating Interpretable Reinforcement Learning by Distilling Policies into Programscited by 3
- 2025Information Templates: A New Paradigm for Intelligent Active Feature Acquisitioncited by 2
- 2025Inducing, Detecting and Characterising Neural Modules: A Pipeline for Functional Interpretability in Reinforcement Learningcited by 1
- 2026Approximation-Free Differentiable Oblique Decision Treescited by 0
- 2026ConceptTree: Bringing Semantic Transparency to Black-Box Decision Making for Robotic Manipulationcited by 0
- 2026ConceptTree: Bringing Semantic Transparency to Black-Box Decision Making for Robotic Manipulation20 Jul 2026
- 2026Approximation-Free Differentiable Oblique Decision Trees8 May 2026
- 2025Information Templates: A New Paradigm for Intelligent Active Feature Acquisition25 Aug 2025
- 2025Evaluating Interpretable Reinforcement Learning by Distilling Policies into Programs11 Mar 2025
- 2025Inducing, Detecting and Characterising Neural Modules: A Pipeline for Functional Interpretability in Reinforcement Learning28 Jan 2025