Studying the Interplay Between the Actor and Critic Representations in Reinforcement Learning

Fuente: arXiv
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Hauptverfasser: Garcin, Samuel, McInroe, Trevor, Castro, Pablo Samuel, Panangaden, Prakash, Lucas, Christopher G., Abel, David, Albrecht, Stefano V.
Format: Preprint
Veröffentlicht: 2025
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author Garcin, Samuel
McInroe, Trevor
Castro, Pablo Samuel
Panangaden, Prakash
Lucas, Christopher G.
Abel, David
Albrecht, Stefano V.
author_facet Garcin, Samuel
McInroe, Trevor
Castro, Pablo Samuel
Panangaden, Prakash
Lucas, Christopher G.
Abel, David
Albrecht, Stefano V.
contents Extracting relevant information from a stream of high-dimensional observations is a central challenge for deep reinforcement learning agents. Actor-critic algorithms add further complexity to this challenge, as it is often unclear whether the same information will be relevant to both the actor and the critic. To this end, we here explore the principles that underlie effective representations for the actor and for the critic in on-policy algorithms. We focus our study on understanding whether the actor and critic will benefit from separate, rather than shared, representations. Our primary finding is that when separated, the representations for the actor and critic systematically specialise in extracting different types of information from the environment -- the actor's representation tends to focus on action-relevant information, while the critic's representation specialises in encoding value and dynamics information. We conduct a rigourous empirical study to understand how different representation learning approaches affect the actor and critic's specialisations and their downstream performance, in terms of sample efficiency and generation capabilities. Finally, we discover that a separated critic plays an important role in exploration and data collection during training. Our code, trained models and data are accessible at https://github.com/francelico/deac-rep.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06343
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Studying the Interplay Between the Actor and Critic Representations in Reinforcement Learning
Garcin, Samuel
McInroe, Trevor
Castro, Pablo Samuel
Panangaden, Prakash
Lucas, Christopher G.
Abel, David
Albrecht, Stefano V.
Machine Learning
Artificial Intelligence
Extracting relevant information from a stream of high-dimensional observations is a central challenge for deep reinforcement learning agents. Actor-critic algorithms add further complexity to this challenge, as it is often unclear whether the same information will be relevant to both the actor and the critic. To this end, we here explore the principles that underlie effective representations for the actor and for the critic in on-policy algorithms. We focus our study on understanding whether the actor and critic will benefit from separate, rather than shared, representations. Our primary finding is that when separated, the representations for the actor and critic systematically specialise in extracting different types of information from the environment -- the actor's representation tends to focus on action-relevant information, while the critic's representation specialises in encoding value and dynamics information. We conduct a rigourous empirical study to understand how different representation learning approaches affect the actor and critic's specialisations and their downstream performance, in terms of sample efficiency and generation capabilities. Finally, we discover that a separated critic plays an important role in exploration and data collection during training. Our code, trained models and data are accessible at https://github.com/francelico/deac-rep.
title Studying the Interplay Between the Actor and Critic Representations in Reinforcement Learning
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2503.06343