Limitations of Codebook Interpretability in Model-Based Reinforcement Learning

Original paper: https://arxiv.org/abs/2407.19532

Title: The Interpretability of Codebooks in Model-Based Reinforcement Learning is Limited

Authors: Kenneth Eaton, Jonathan Balloch, Julia Kim, Mark Riedl

Abstract:
Interpretability of deep reinforcement learning systems could assist operators with understanding how they interact with their environment. Vector quantization methods -- also called codebook methods -- discretize a neural network's latent space that is often suggested to yield emergent interpretability. We investigate whether vector quantization in fact provides interpretability in model-based reinforcement learning. Our experiments, conducted in the reinforcement learning environment Crafter, show that the codes of vector quantization models are inconsistent, have no guarantee of uniqueness, and have a limited impact on concept disentanglement, all of which are necessary traits for interpretability. We share insights on why vector quantization may be fundamentally insufficient for model interpretability.