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Actor-Critic

A reinforcement learning architecture with two components: an actor (policy) that selects actions, and a critic (value function) that evaluates those actions.

robotics model-based-rl simulation embodied-ai

What Is Actor-Critic?

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A reinforcement learning architecture with two components: an actor (policy) that selects actions, and a critic (value function) that evaluates those actions. In world models like DreamerV3, both actor and critic are trained entirely within imagination.

Actor-Critic is a glossary concept in the training layer of the world models knowledge base.

Term Snapshot

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AttributeValue
TermActor-Critic
CategoryTraining
DefinitionA reinforcement learning architecture with two components: an actor (policy) that selects actions, and a critic (value function) that evaluates those actions. In world models like DreamerV3, both actor and critic are trained entirely within imagination.
Related Models3
Related Research1

Related Models

ModelLabCategory
DreamerV3Google DeepMindModel-Based RL
DreamerV2GoogleModel-Based RL
TD-MPC2MIT / MetaModel-Based RL

Related Research

TopicSummary
Model-Based Reinforcement LearningWhat model-based reinforcement learning is, how world models enable imagination-based planning, and why Dreamer, MuZero, PlaNet, and TD-MPC2 matter.

Related Terms

TermCategoryDefinition
Imagination-Based LearningTrainingA training paradigm where an agent uses its world model to generate synthetic (imagined) trajectories, then learns policies from these imagined experiences rather than costly real-world interaction. This dramatically improves sample efficiency.
Model-Based Reinforcement LearningParadigmsAn RL approach where the agent learns a predictive model of the environment (a world model) and uses it to simulate outcomes, plan ahead, and learn from imagined experience. Contrasted with model-free RL which learns directly from interaction.

Quick Answer

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  • Actor-Critic is a glossary concept used across world-models.io to clarify language, methods, and architectural ideas in the field.
  • Use this page to get the definition quickly, then continue into related models, research topics, and adjacent terms for context.

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Published by world-models.io editorial board.

Lead editor Bernard Grenat.

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