Loss of Plasticity in Continual Deep Reinforcement Learning
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Abstract (arXiv)
The ability to learn continually is essential in a complex and changing world. In this paper, we characterize the behavior of canonical value-based deep reinforcement learning (RL) approaches under varying degrees of non-stationarity. In particular, we demonstrate that deep RL agents lose their ability to learn good policies when they cycle through a sequence of Atari 2600 games. This phenomenon is alluded to in prior work under various guises -- e.g., loss of plasticity, implicit under-parameterization, primacy bias, and capacity loss. We investigate this phenomenon closely at scale and analyze how the weights, gradients, and activations change over time in several experiments with varying dimensions (e.g., similarity between games, number of games, number of frames per game), with some experiments spanning 50 days and 2 billion environment interactions. Our analysis shows that the activation footprint of the network becomes sparser, contributing to the diminishing gradients. We investigate a remarkably simple mitigation strategy -- Concatenated ReLUs (CReLUs) activation function -- and demonstrate its effectiveness in facilitating continual learning in a changing environment.
Key facts. Cited by 118 papers in the map (data through 7 Oct 2026). Builds on 21 of its 37 references that are in the map. First posted on arXiv 13 Mar 2023.
Builds on
21 of 37 references.
References · 21
- 2019Meta-World: A Benchmark and Evaluation for Multi-Task and Meta Reinforcement Learningcited by 1,168
- 2015Prioritized Experience Replaycited by 1,070
- 2022A Generalist Agentcited by 802
- 2017Rainbow: Combining Improvements in Deep Reinforcement Learningcited by 774
- 2015Dueling Network Architectures for Deep Reinforcement Learningcited by 769
- 2017A Distributional Perspective on Reinforcement Learningcited by 743
- 2020Towards Continual Reinforcement Learning: A Review and Perspectivescited by 268
- 2017Revisiting the Arcade Learning Environment: Evaluation Protocols and Open Problems for General Agentscited by 267
- 2017Noisy Networks for Explorationcited by 262
- 2022The Primacy Bias in Deep Reinforcement Learningcited by 242
- 2020Implicit Under-Parameterization Inhibits Data-Efficient Deep Reinforcement Learningcited by 134
- 2022Understanding and Preventing Capacity Loss in Reinforcement Learningcited by 124
9 more
- 2018Generalization and Regularization in DQNcited by 117
- 2016Understanding and Improving Convolutional Neural Networks via Concatenated Rectified Linear Unitscited by 86
- 2021Continual Backprop: Stochastic Gradient Descent with Persistent Randomnesscited by 79
- 2021DeepThermal: Combustion Optimization for Thermal Power Generating Units Using Offline Reinforcement Learningcited by 47
- 2022MuZero with Self-competition for Rate Control in VP9 Video Compressioncited by 27
- 2022Controlling Commercial Cooling Systems Using Reinforcement Learningcited by 25
- 2022Investigating the Properties of Neural Network Representations in Reinforcement Learningcited by 24
- 2022Deep Inventory Managementcited by 22
- 2022Probing Transfer in Deep Reinforcement Learning without Task Engineeringcited by 4
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Citing papers per year: 2023: 14; 2024: 32; 2025: 39; 2026: 33.
118 papers.
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- 2023A Definition of Continual Reinforcement Learningcited by 98
- 2024Disentangling the Causes of Plasticity Loss in Neural Networkscited by 82
- 2025Lifelong Learning of Large Language Model based Agents: A Roadmapcited by 78
- 2023Deep Reinforcement Learning with Plasticity Injectioncited by 71
- 2023Maintaining Plasticity in Continual Learning via Regenerative Regularizationcited by 63
- 2024Normalization and effective learning rates in reinforcement learningcited by 55
- 2025FLEX: Continuous Agent Evolution via Forward Learning from Experiencecited by 51
- 2024Overestimation, Overfitting, and Plasticity in Actor-Critic: the Bitter Lesson of Reinforcement Learningcited by 50
- 2024Addressing Loss of Plasticity and Catastrophic Forgetting in Continual Learningcited by 49
- 2023PLASTIC: Improving Input and Label Plasticity for Sample Efficient Reinforcement Learningcited by 42
- 2023Maintaining Plasticity in Deep Continual Learningcited by 42
- 2023AMAGO: Scalable In-Context Reinforcement Learning for Adaptive Agentscited by 36
38 more
- 2024Learning Continually by Spectral Regularizationcited by 34
- 2024Weight Clipping for Deep Continual and Reinforcement Learningcited by 29
- 2023Revisiting Plasticity in Visual Reinforcement Learning: Data, Modules and Training Stagescited by 27
- 2024No Representation, No Trust: Connecting Representation, Collapse, and Trust Issues in PPOcited by 27
- 2023Resetting the Optimizer in Deep RL: An Empirical Studycited by 26
- 2023Directions of Curvature as an Explanation for Loss of Plasticitycited by 26
- 2024A Study of Plasticity Loss in On-Policy Deep Reinforcement Learningcited by 26
- 2023Symmetry Induces Structure and Constraint of Learningcited by 25
- 2024Streaming Deep Reinforcement Learning Finally Workscited by 24
- 2024Plasticity Loss in Deep Reinforcement Learning: A Surveycited by 24
- 2025Mitigating Plasticity Loss in Continual Reinforcement Learning by Reducing Churncited by 22
- 2025Stable Gradients for Stable Learning at Scale in Deep Reinforcement Learningcited by 22
- 2024Mixture of Experts in a Mixture of RL settingscited by 21
- 2024Scalable Reinforcement Post-Training Beyond Static Human Prompts: Evolving Alignment via Asymmetric Self-Playcited by 21
- 2024Parseval Regularization for Continual Reinforcement Learningcited by 21
- 2024Dissecting Deep RL with High Update Ratios: Combatting Value Divergencecited by 17
- 2024Neuroplastic Expansion in Deep Reinforcement Learningcited by 17
- 2024Non-Stationary Learning of Neural Networks with Automatic Soft Parameter Resetcited by 17
- 2024Fast TRAC: A Parameter-Free Optimizer for Lifelong Reinforcement Learningcited by 16
- 2024Improving Deep Reinforcement Learning by Reducing the Chain Effect of Value and Policy Churncited by 16
- 2024MAD-TD: Model-Augmented Data stabilizes High Update Ratio RLcited by 16
- 2025A Survey of Continual Reinforcement Learningcited by 16
- 2024Can Learned Optimization Make Reinforcement Learning Less Difficult?cited by 14
- 2024Plastic Learning with Deep Fourier Featurescited by 14
- 2025Measure gradients, not activations! Enhancing neuronal activity in deep reinforcement learningcited by 14
- 2026Simple Recipe Works: Vision-Language-Action Models are Natural Continual Learners with Reinforcement Learningcited by 13
- 2025Simplicial Embeddings Improve Sample Efficiency in Actor-Critic Agentscited by 12
- 2025Plasticity as the Mirror of Empowermentcited by 11
- 2025Network Sparsity Unlocks the Scaling Potential of Deep Reinforcement Learningcited by 11
- 2023Harnessing Discrete Representations For Continual Reinforcement Learningcited by 10
- 2024Learning Successor Features the Simple Waycited by 10
- 2024Position: Lifetime tuning is incompatible with continual reinforcement learningcited by 9
- 2023On the Importance of Feature Decorrelation for Unsupervised Representation Learning in Reinforcement Learningcited by 8
- 2024Integrating Present and Past in Unsupervised Continual Learningcited by 8
- 2024Remove Symmetries to Control Model Expressivity and Improve Optimizationcited by 8
- 2024SPIRE: Synergistic Planning, Imitation, and Reinforcement Learning for Long-Horizon Manipulationcited by 8
- 2025MEAL: A Benchmark for Continual Multi-Agent Reinforcement Learningcited by 8
- 2025Continual Reinforcement Learning by Planning with Online World Modelscited by 8
50 most cited of 118 All 118 (JSON)
- 2026Policy Plasticity Matters in Offline-to-Online Reinforcement Learning: Refitting Offline Policies for Online Adaptation27 Sep 2026
- 2026From Static Policies to Adaptive Priors in Offline Reinforcement Learning26 Sep 2026
- 2026Rank Collapse Is Recoverable, Growing |Q| Is Not: Out-of-Sample Early Warning for Value Divergence in High-UTD Soft Actor-Critic26 Sep 2026
- 2026Mind the Phase: Effective Rank and Representation Health in Legged Locomotion7 Sep 2026
- 2026Dimensionless Controls of Plasticity Under Alternating Tasks: From Evolutionary Biology to Continual Learning24 Aug 2026
- 2026Adjustment Speed as a Safety Constraint for Nonstationary Reinforcement Learning21 Jul 2026
- 2026PRIME: Plasticity Recovery in Multi-Agent Environments for UAV-Assisted Emergency Communication Networks20 Jul 2026
- 2026Local Redundancy: An Information-Theoretic Measure of Plasticity from Synthetic Memorization15 Jul 2026
- 2026Can Scale Save Us From Plasticity Loss in Large Language Models?23 Jun 2026
- 2026Preserving Plasticity in Continual Learning via Dynamical Isometry8 Jun 2026
- 2026Continual Quadruped Robots Coordination via Semantic Skill Discovery6 Jun 2026
- 2026Local Guidance, Global Impact: Gaussian-Reshaped Trust Region Unlocks Behavior Transitions2 Jun 2026
38 more
- 2026Position: Deployed Reinforcement Learning should be Continual1 Jun 2026
- 2026Task-Induced Representational Invariances Depend on Learning Objective in Deep RL1 Jun 2026
- 2026Don't Forget the Critic: Value-Based Data Rehearsal for Multi-Cyclic Continual Reinforcement Learning21 May 2026
- 2026Emergent Sparsity in Frozen Random CNN Feature Extractors for Deep Reinforcement Learning15 May 2026
- 2026On the Stability of Growth in Structural Plasticity: Forward-Active yet Backward-Starved14 May 2026
- 2026Angel or Demon: Investigating the Plasticity Interventions' Impact on Backdoor Threats in Deep Reinforcement Learning14 May 2026
- 2026Higher Resolution, Better Generalization: Unlocking Visual Scaling in Deep Reinforcement Learning11 May 2026
- 2026Predicting Plasticity in Deep Continual Learning: A Theoretical Perspective9 May 2026
- 2026SPHERE: Mitigating the Loss of Spectral Plasticity in Mixture-of-Experts for Deep Reinforcement Learning6 May 2026
- 2026Forager: a lightweight testbed for continual learning with partial observability in RL1 May 2026
- 2026Safe Continual Reinforcement Learning in Non-stationary Environments21 Apr 2026
- 2026Task Switching Without Forgetting via Proximal Decoupling20 Apr 2026
- 2026Beyond Single-Model Optimization: Preserving Plasticity in Continual Reinforcement Learning16 Apr 2026
- 2026Plasticity-Enhanced Multi-Agent Mixture of Experts for Dynamic Objective Adaptation in UAVs-Assisted Emergency Communication Networks10 Apr 2026
- 2026FlashSAC: Fast and Stable Off-Policy Reinforcement Learning for High-Dimensional Robot Control6 Apr 2026
- 2026Rethinking Plasticity in Deep Reinforcement Learning22 Mar 2026
- 2026Simple Recipe Works: Vision-Language-Action Models are Natural Continual Learners with Reinforcement Learning12 Mar 2026
- 2026Overcoming Valid Action Suppression in Unmasked Policy Gradient Algorithms10 Mar 2026
- 2026Vision Transformers that Never Stop Learning8 Mar 2026
- 2026Do Neural Networks Lose Plasticity in a Gradually Changing World?9 Feb 2026
- 2026CRoSS: A Continual Robotic Simulation Suite for Scalable Reinforcement Learning with High Task Diversity and Realistic Physics Simulation4 Feb 2026
- 2025Towards better dense rewards in Reinforcement Learning Applications3 Dec 2025
- 2025Intrinsic preservation of plasticity in continual quantum learning21 Nov 2025
- 2025FLEX: Continuous Agent Evolution via Forward Learning from Experience9 Nov 2025
- 2025Continual Knowledge Adaptation for Reinforcement Learning22 Oct 2025
- 2025Simplicial Embeddings Improve Sample Efficiency in Actor-Critic Agents15 Oct 2025
- 2025Rethinking the Role of Dynamic Sparse Training for Scalable Deep Reinforcement Learning14 Oct 2025
- 2025Ergodic Risk Measures: Towards a Risk-Aware Foundation for Continual Reinforcement Learning3 Oct 2025
- 2025Activation Function Design Sustains Plasticity in Continual Learning26 Sep 2025
- 2025Spectral Collapse Drives Loss of Plasticity in Deep Continual Learning26 Sep 2025
- 2025A Unified Noise-Curvature View of Loss of Trainability24 Sep 2025
- 2025Sparsity-Driven Plasticity in Multi-Task Reinforcement Learning9 Aug 2025
- 2025Reinitializing weights vs units for maintaining plasticity in neural networks31 Jul 2025
- 2025What Can Grokking Teach Us About Learning Under Nonstationarity?26 Jul 2025
- 2025How Should We Meta-Learn Reinforcement Learning Algorithms?23 Jul 2025
- 2025Relative Entropy Pathwise Policy Optimization15 Jul 2025
- 2025Continual Reinforcement Learning by Planning with Online World Models12 Jul 2025
- 2025A Survey of Continual Reinforcement Learning27 Jun 2025
50 newest of 118 All 118 (JSON)
- 2024Mixture of Experts in a Mixture of RL settingscited by 21
- 2025Plasticity-Aware Mixture of Experts for Learning Under QoE Shifts in Adaptive Video Streamingcited by 4
- 2026SPHERE: Mitigating the Loss of Spectral Plasticity in Mixture-of-Experts for Deep Reinforcement Learningcited by 2
- 2026Plasticity-Enhanced Multi-Agent Mixture of Experts for Dynamic Objective Adaptation in UAVs-Assisted Emergency Communication Networkscited by 1
- 2026SPHERE: Mitigating the Loss of Spectral Plasticity in Mixture-of-Experts for Deep Reinforcement Learning6 May 2026
- 2026Plasticity-Enhanced Multi-Agent Mixture of Experts for Dynamic Objective Adaptation in UAVs-Assisted Emergency Communication Networks10 Apr 2026
- 2025Plasticity-Aware Mixture of Experts for Learning Under QoE Shifts in Adaptive Video Streaming14 Apr 2025
- 2024Mixture of Experts in a Mixture of RL settings26 Jun 2024
- 2024SPIRE: Synergistic Planning, Imitation, and Reinforcement Learning for Long-Horizon Manipulationcited by 8
- 2026Policy Plasticity Matters in Offline-to-Online Reinforcement Learning: Refitting Offline Policies for Online Adaptationcited by 0
- 2026From Static Policies to Adaptive Priors in Offline Reinforcement Learningcited by 0
- 2026Policy Plasticity Matters in Offline-to-Online Reinforcement Learning: Refitting Offline Policies for Online Adaptation27 Sep 2026
- 2026From Static Policies to Adaptive Priors in Offline Reinforcement Learning26 Sep 2026
- 2024SPIRE: Synergistic Planning, Imitation, and Reinforcement Learning for Long-Horizon Manipulation23 Oct 2024
- 2023A Definition of Continual Reinforcement Learningcited by 98
- 2024Disentangling the Causes of Plasticity Loss in Neural Networkscited by 82
- 2023Deep Reinforcement Learning with Plasticity Injectioncited by 71
- 2023Maintaining Plasticity in Continual Learning via Regenerative Regularizationcited by 63
- 2024Normalization and effective learning rates in reinforcement learningcited by 55
- 2024Overestimation, Overfitting, and Plasticity in Actor-Critic: the Bitter Lesson of Reinforcement Learningcited by 50
- 2024Addressing Loss of Plasticity and Catastrophic Forgetting in Continual Learningcited by 49
- 2023PLASTIC: Improving Input and Label Plasticity for Sample Efficient Reinforcement Learningcited by 42
- 2023Maintaining Plasticity in Deep Continual Learningcited by 42
- 2023AMAGO: Scalable In-Context Reinforcement Learning for Adaptive Agentscited by 36
- 2024Learning Continually by Spectral Regularizationcited by 34
- 2024Weight Clipping for Deep Continual and Reinforcement Learningcited by 29
12 most cited of 103 All 103 (JSON)
- 2026Rank Collapse Is Recoverable, Growing |Q| Is Not: Out-of-Sample Early Warning for Value Divergence in High-UTD Soft Actor-Critic26 Sep 2026
- 2026Mind the Phase: Effective Rank and Representation Health in Legged Locomotion7 Sep 2026
- 2026Dimensionless Controls of Plasticity Under Alternating Tasks: From Evolutionary Biology to Continual Learning24 Aug 2026
- 2026Adjustment Speed as a Safety Constraint for Nonstationary Reinforcement Learning21 Jul 2026
- 2026PRIME: Plasticity Recovery in Multi-Agent Environments for UAV-Assisted Emergency Communication Networks20 Jul 2026
- 2026Local Redundancy: An Information-Theoretic Measure of Plasticity from Synthetic Memorization15 Jul 2026
- 2026Can Scale Save Us From Plasticity Loss in Large Language Models?23 Jun 2026
- 2026Preserving Plasticity in Continual Learning via Dynamical Isometry8 Jun 2026
- 2026Continual Quadruped Robots Coordination via Semantic Skill Discovery6 Jun 2026
- 2026Local Guidance, Global Impact: Gaussian-Reshaped Trust Region Unlocks Behavior Transitions2 Jun 2026
- 2026Position: Deployed Reinforcement Learning should be Continual1 Jun 2026
- 2026Task-Induced Representational Invariances Depend on Learning Objective in Deep RL1 Jun 2026
12 newest of 103 All 103 (JSON)