Empowerment-driven Policy Gradient Learning with Counterfactual Augmentation in Recommender Systems

Abstract

Deep reinforcement learning (DRL) has been proven its efficiency in capturing users’ dynamic interests in recent literature. However, training a DRL agent is challenging, because of the sparse environment in recommender systems (RS), DRL agents could spend times either exploring informative user-item interaction trajectories or using existing trajectories for policy learning. It is also known as the exploration and exploitation trade-off which affects the recommendation performance significantly when the environment is sparse. It is more challenging to balance the exploration and exploitation in DRL RS where RS agent need to deeply explore the informative trajectories and exploit them efficiently in the context of recommender systems. As a step to address this issue, We design a novel empowerment-driven exploration method to increase the capability of exploring informative interaction trajectories in the sparse environment, which are further enriched via a counterfactual augmentation strategy for more efficient exploitation. The extensive experiments on four offline datasets and an online simulation platform demonstrate the superiority of our model to a set of existing state-of-the-art methods.