Human-Allied Relational Reinforcement Learning
Fateme Golivand Darvishvand, Hikaru Shindo, Sahil Sidheekh, Kristian Kersting, Sriraam Natarajan
TL;DR
The paper tackles the challenge of learning symbolic, relational policies in both structured and unstructured domains, where traditional deep RL struggles with generalization and interpretability. It proposes RAEL, a framework that combines Relational RL with object-centric representations and active human advice, guided by a budget on expert queries and a soft constraint incorporation via policy reuse. RAEL uses Relational Fitted Q-learning (RFQ) with gradient-boosted relational regression trees and an object-centric extractor to convert unstructured inputs into symbolic states, while actively querying a human in high-uncertainty states to improve sample efficiency and policy fidelity. Experiments across Atari-based sub-symbolic tasks and the Blocks World domain demonstrate improved performance, faster convergence with abstraction-guided advice, and the practical viability of human-in-the-loop, symbolic RL for complex environments.
Abstract
Reinforcement learning (RL) has experienced a second wind in the past decade. While incredibly successful in images and videos, these systems still operate within the realm of propositional tasks ignoring the inherent structure that exists in the problem. Consequently, relational extensions (RRL) have been developed for such structured problems that allow for effective generalization to arbitrary number of objects. However, they inherently make strong assumptions about the problem structure. We introduce a novel framework that combines RRL with object-centric representation to handle both structured and unstructured data. We enhance learning by allowing the system to actively query the human expert for guidance by explicitly modeling the uncertainty over the policy. Our empirical evaluation demonstrates the effectiveness and efficiency of our proposed approach.
