Exploring the Noise Resilience of Successor Features and Predecessor Features Algorithms in One and Two-Dimensional Environments

Abstract

Based on the predictive map theory of spatial learning in animals, this study delves into the dynamics of Successor Feature (SF) and Predecessor Feature (PF) algorithms within noisy environments. Utilizing Q-learning and Q($\lambda$) learning as benchmarks for comparative analysis, our investigation yielded unexpected outcomes. Contrary to prevailing expectations and previous literature where PF demonstrated superior performance, our findings reveal that in noisy environments, PF did not surpass SF. In a one-dimensional grid world, SF exhibited superior adaptability, maintaining robust performance across varying noise levels. This trend of diminishing performance with increasing noise was consistent across all examined algorithms, indicating a linear degradation pattern. The scenario shifted in a two-dimensional grid world, where the impact of noise on algorithm performance demonstrated a non-linear relationship, influenced by the $\lambda$ parameter of the eligibility trace. This complexity suggests that the interaction between noise and algorithm efficacy is tied to the environmental dimensionality and specific algorithmic parameters. Furthermore, this research contributes to the bridging discourse between computational neuroscience and reinforcement learning (RL), exploring the neurobiological parallels of SF and PF learning in spatial navigation. Despite the unforeseen performance trends, the findings enrich our comprehension of the strengths and weaknesses inherent in RL algorithms. This knowledge is pivotal for advancing applications in robotics, gaming AI, and autonomous vehicle navigation, underscoring the imperative for continued exploration into how RL algorithms process and learn from noisy inputs.