Pointwise-in-time diagnostics for reinforcement learning during training and runtime

Explainable AI Planning (XAIP), a subfield of xAI, offers a variety of methods to interpret the behavior of autonomous systems. A recent “pointwise-in-time” explanation method, called Rule Status Assessment (RSA), characterizes an agent’s behavior at individual time steps in a trajectory using linear temporal logic (LTL) rules. In this work, RSA is applied for the first time in a reinforcement learning (RL) context. We first demonstrate RSA diagnostics as a substantial supplement to the basic RL reward curve, tracking whether and when specified subtasks are accomplished. We then introduce a novel “Interactive RSA” which provides the user with detailed diagnostic information automatically at any desired point in a trajectory. We apply RSA to an advanced agent at runtime and show that RSA and its novel interactive variant constitute a promising step towards explainable RL.