TACO: Temporal Latent Action-Driven Contrastive Loss for Visual Reinforcement Learning
Ruijie Zheng, Xiyao Wang, Yanchao Sun, Shuang Ma, Jieyu Zhao, Huazhe Xu, Hal Daumé, Furong Huang
TL;DR
TACO addresses sample inefficiency in visual reinforcement learning by learning concurrent state and action representations via a temporal contrastive objective that maximizes the mutual information $J_{ ext{TACO}}=\mathcal{I}(Z_{t+K}; [Z_t, U_t, ..., U_{t+K-1}])$. It provides a theoretically sufficient objective for control and is designed as a plug-in module compatible with online and offline RL pipelines using a DrQ-v2 backbone, with horizon $K$ typically $1$ or $3$. Empirically, TACO achieves about a 40% average performance boost after 1M environment steps across nine DM Control Suite tasks in online RL and sets new state-of-the-art results for offline visual RL when paired with strong baselines like TD3+BC and CQL across diverse datasets. The work highlights the importance of learning action representations in continuous control and demonstrates that a stable, MI-based objective can effectively capture dynamics for improved sample efficiency and generalization.
Abstract
Despite recent progress in reinforcement learning (RL) from raw pixel data, sample inefficiency continues to present a substantial obstacle. Prior works have attempted to address this challenge by creating self-supervised auxiliary tasks, aiming to enrich the agent's learned representations with control-relevant information for future state prediction. However, these objectives are often insufficient to learn representations that can represent the optimal policy or value function, and they often consider tasks with small, abstract discrete action spaces and thus overlook the importance of action representation learning in continuous control. In this paper, we introduce TACO: Temporal Action-driven Contrastive Learning, a simple yet powerful temporal contrastive learning approach that facilitates the concurrent acquisition of latent state and action representations for agents. TACO simultaneously learns a state and an action representation by optimizing the mutual information between representations of current states paired with action sequences and representations of the corresponding future states. Theoretically, TACO can be shown to learn state and action representations that encompass sufficient information for control, thereby improving sample efficiency. For online RL, TACO achieves 40% performance boost after one million environment interaction steps on average across nine challenging visual continuous control tasks from Deepmind Control Suite. In addition, we show that TACO can also serve as a plug-and-play module adding to existing offline visual RL methods to establish the new state-of-the-art performance for offline visual RL across offline datasets with varying quality.
