Explaining Learned Reward Functions with Counterfactual Trajectories

Fuente: arXiv
Enregistré dans:
Détails bibliographiques
Auteurs principaux: Wehner, Jan, Oliehoek, Frans, Siebert, Luciano Cavalcante
Format: Preprint
Publié: 2024
Sujets:
Accès en ligne:
Tags: Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
_version_ 1866910650018562048
author Wehner, Jan
Oliehoek, Frans
Siebert, Luciano Cavalcante
author_facet Wehner, Jan
Oliehoek, Frans
Siebert, Luciano Cavalcante
contents Learning rewards from human behaviour or feedback is a promising approach to aligning AI systems with human values but fails to consistently extract correct reward functions. Interpretability tools could enable users to understand and evaluate possible flaws in learned reward functions. We propose Counterfactual Trajectory Explanations (CTEs) to interpret reward functions in reinforcement learning by contrasting an original with a counterfactual partial trajectory and the rewards they each receive. We derive six quality criteria for CTEs and propose a novel Monte-Carlo-based algorithm for generating CTEs that optimises these quality criteria. Finally, we measure how informative the generated explanations are to a proxy-human model by training it on CTEs. CTEs are demonstrably informative for the proxy-human model, increasing the similarity between its predictions and the reward function on unseen trajectories. Further, it learns to accurately judge differences in rewards between trajectories and generalises to out-of-distribution examples. Although CTEs do not lead to a perfect understanding of the reward, our method, and more generally the adaptation of XAI methods, are presented as a fruitful approach for interpreting learned reward functions.
format Preprint
id arxiv_https___arxiv_org_abs_2402_04856
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Explaining Learned Reward Functions with Counterfactual Trajectories
Wehner, Jan
Oliehoek, Frans
Siebert, Luciano Cavalcante
Artificial Intelligence
Machine Learning
Learning rewards from human behaviour or feedback is a promising approach to aligning AI systems with human values but fails to consistently extract correct reward functions. Interpretability tools could enable users to understand and evaluate possible flaws in learned reward functions. We propose Counterfactual Trajectory Explanations (CTEs) to interpret reward functions in reinforcement learning by contrasting an original with a counterfactual partial trajectory and the rewards they each receive. We derive six quality criteria for CTEs and propose a novel Monte-Carlo-based algorithm for generating CTEs that optimises these quality criteria. Finally, we measure how informative the generated explanations are to a proxy-human model by training it on CTEs. CTEs are demonstrably informative for the proxy-human model, increasing the similarity between its predictions and the reward function on unseen trajectories. Further, it learns to accurately judge differences in rewards between trajectories and generalises to out-of-distribution examples. Although CTEs do not lead to a perfect understanding of the reward, our method, and more generally the adaptation of XAI methods, are presented as a fruitful approach for interpreting learned reward functions.
title Explaining Learned Reward Functions with Counterfactual Trajectories
topic Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2402.04856