Continual learning requires balancing plasticity and stability while mitigating catastrophic forgetting. Inspired by human dreaming as a mechanism for internal simulation and knowledge restructuring, we introduce Dream2Learn (D2L), a framework in which a model autonomously generates structured synthetic experiences from its own internal representations and uses them for self-improvement. Rather than reconstructing past data as in generative replay, D2L enables a classifier to create novel, semantically distinct dreamed classes that are coherent with its learned knowledge yet do not correspond to previously observed data. These dreamed samples are produced by conditioning a frozen diffusion model through soft prompt optimization driven by the classifier itself. The generated data are not used to replace memory, but to expand and reorganize the representation space, effectively allowing the network to self-train on internally synthesized concepts. By integrating dreamed classes into continual training, D2L proactively structures latent features to support forward knowledge transfer and adaptation to future tasks. This prospective self-training mechanism mirrors the role of sleep in consolidating and reorganizing memory, turning internal simulations into a tool for improved generalization. Experiments on Mini-ImageNet, FG-ImageNet, and ImageNet-R demonstrate that D2L consistently outperforms strong rehearsal-based baselines and achieves positive forward transfer, confirming its ability to enhance adaptability through internally generated training signals.
Figures & tables
Figure 1: Dreamed classes generated by D2L . Examples of dreamed classes synthesized from their corresponding real classes (left). These samples emerge as semantically distinct yet structurally coherent representations in the generator’s latent space, forming intermediate concepts that enhance the continual classifier’s generalization to future tasks.
Figure 2: Overview of Dream2Learn. (1) During CL training, a deep neural network (DNN) learns from real sensory images (the current task distribution plus the buffer) and dreamed samples produced by a latent diffusion model (LDM). (2) The dreaming optimization process refines the LDM prompts, with an Oracle Network providing a stopping criterion that prevents collapse. (3) Prompts generate auxiliary classes: dreamed samples are not buffered, but rather enrich the representation space with coherent latent clusters that foster knowledge reuse and adaptation.
Figure 3: Visualization of the dreaming optimization process in the latent space of a LDM. Given a real sample x , the optimization refines the soft prompt psoft,c to steer the diffusion model towards generating a dreamed counterpart that aligns with the target class c (e.g., a green mamba in this example). The dreaming process explores latent regions where images are visually similar yet distinct from target classes, forming novel intermediate classes (violet zones).
Figure 4: Examples of dreaming optimization trajectories showing collapse . From left to right, the images depict different stages of the optimization process. Each row illustrates the evolution of three example images throughout the same prompt optimization. Initially, the generated samples maintain meaningful variations. However, as optimization progresses, they become increasingly similar, reducing diversity and leading to less effective representations.
Mini-ImageNet
FG-ImageNet
ImageNet-R
2000
5000
2000
5000
2000
5000
ER
27.91 ± 3.49
34.21 ± 3.04
21.08 ± 2.38
22.21 ± 3.44
7.68 ± 0.97
10.69 ± 1.29
↪ D2L
31.18 ± 2.74
39.75 ± 2.61
23.53 ± 1.98
32.73 ± 3.39
8.67 ± 0.66
11.84 ± 0.95
DER++
14.74 ± 2.14
26.92 ± 4.72
14.43 ± 3.68
23.86 ± 2.54
6.08 ± 0.81
8.29 ± 1.15
↪ D2L
21.06 ± 5.45
31.91 ± 5.19
18.86 ± 3.22
25.38 ± 2.17
8.60 ± 1.00
10.89 ± 1.56
ER-ACE
33.26 ± 3.51
40.59 ± 1.20
24.79 ± 5.02
30.16 ± 4.97
7.09 ± 0.59
9.44 ± 0.70
Table 1: Class-incremental final average accuracy (FAA) of rehearsal-based methods , with and without dreaming, for buffer sizes 2000 and 5000.
Mini-ImageNet
FG-ImageNet
ImageNet-R
2000
5000
2000
5000
2000
5000
ER
-2.58
-1.62
-1.88
-1.52
-1.32
-0.64
↪ D2L
+0.33
+0.47
+1.79
+1.19
+0.24
+0.14
DER++
-1.55
-2.00
-1.36
-2.48
-1.03
-1.83
↪ D2L
+0.97
+0.71
-0.13
+1.86
+0.30
+0.24
ER-ACE
-1.99
-2.45
-2.00
-2.16
-2.46
-1.27
Table 2: Forward Transfer (FWT) of rehearsal-based methods , with and without dreaming, for buffer sizes 2000 and 5000.
Method
Mini-ImageNet
FG-ImageNet
ImageNet-R
Fine-tune
6.72 ± 1.20
6.98 ± 0.10
4.46 ± 0.15
Buffer-based methods
2000
5000
2000
5000
2000
5000
GSS
6.40 ± 0.38
5.71 ± 0.08
8.07 ± 0.26
9.23 ± 0.85
5.08 ± 0.13
4.29 ± 0.32
A-GEM
6.78 ± 1.13
7.45 ± 0.76
6.20 ± 1.11
6.11 ± 1.13
4.69 ± 0.03
6.29 ± 0.84
RPC
9.22 ± 0.30
9.02 ± 0.24
8.13 ± 0.11
7.41 ± 0.74
5.71 ± 0.03
6.32 ± 0.80
Table 3: Comparison with state-of-the-art methods, in terms of class-incremental final average accuracy (FAA) , for buffer sizes 2000 and 5000.
Buffer size
Method
2000
5000
ER-ACE
33.26 ± 3.51
40.59 ± 1.20
+ Fixed optim.
38.94 ± 0.97
46.41 ± 0.55
+ Oracle (D2L)
40.90 ± 0.95
47.32 ± 0.89
Table 4: Ablation on the oracle. Results on Mini-ImageNet comparing our method with Fixed optimization.
Buffer size
Dreaming
2000
5000
No dreams
33.36 ± 3.51
40.59 ± 1.20
At beginning
36.93 ± 2.09
41.59 ± 2.54
Incremental
36.85 ± 1.16
43.87 ± 2.90
D2L
40.90 ± 0.95
47.32 ± 0.89
Table 5: Impact of dream class updates. Comparison on Mini-ImageNet of different dreaming strategies.
Buffer size
Method
2000
5000
ER-ACE
33.26 ± 3.51
40.59 ± 1.20
+ Mixup
36.84 ± 0.94
44.82 ± 1.27
+ Continual Mixup
36.05 ± 1.22
43.45 ± 0.83
+ Textual Mixup
31.89 ± 0.50
–
+ Synth Mixup
36.99 ± 0.26
–
Table 6: Comparison of alterative dream generation strategies. Evaluation on Mini-ImageNet comparing interpolation-based baselines and WSCL (auxiliary-data surrogate against our proposed D2L.
Method
Diffusion Usage
Training cost
Inference cost
Avg. Acc. ( ↑ )
ER-ACE
None
1×
1×
33.26 ± 3.51
+ Mixup
None
1×
1×
36.84 ± 0.94
+ Diffusion (Augmentation + Rehearsal)
Frozen (samples only)
∼7×
1×
36.69 ± 0.42
DDGR (ResNet)
Generator trained (Replay)
∼489×
1×
43.46 ± 0.25
D2L (Ours)
Frozen + Dream classes
∼17×
1×
40.90 ± 0.95
Table 7: Relative training cost per task normalized to ER-ACE ( 1× ) on SeqMiniImageNet. ER-ACE serves as the reference cost model. We report training cost under different diffusion usage regimes (none, augmentation/rehearsal with frozen generator, generator-trained replay, and dreaming). Inference cost remains identical across methods ( 1× ). A detailed cost decomposition is provided in Appendix Appendix B. Computational Cost Estimation .
Table 8: Computational Analysis and Paradigm Comparison. We report the Relative Training Cost normalized to the standard ER-ACE baseline ( 1× ). We also report a per-task TFLOPs Breakdown and the corresponding Total TFLOPs .
The past few decades have witnessed significant advances in the design of machine learning algorithms, from early studies on task-specific shallow models to more general deep Large Language Models (LLMs). Despite showing promising results in tasks that require instant prediction or in-context learning, existing models lack the ability to continually learn and effectively transfer their temporal in-context knowledge to their long-term parameters. Inspired by human learning process, we introduce a ''Sleep'' paradigm that allows the models to continually learn, distill their short-term fragile memories into stable long-term knowledge with replay, and recursively improve themselves with ''Dreaming'' process. In more detail, sleep consists of two stages: (1) Memory Consolidation: an upward distillation process, called Knowledge Seeding, where the memories of a smaller-self are distilled into a larger network to provide more capacity while preserving the knowledge. As a proof of concept, we present a new Generalized Distillation process for {Knowledge Seeding} (i.e., the combination of on-policy distillation with Reinforcement Learning (RL)-based imitation learning); (2) Dreaming: a self-improvement phase, where the model uses RL to generate a curriculum of synthetic data to rehearse new knowledge and refine existing capabilities without human supervision. Our experiments on long-horizon, continual learning, knowledge incorporation, and few-shot generalization tasks support the importance of the sleep stage.
Class-incremental learning (CIL) requires models to continuously acquire new knowledge while avoiding catastrophic forgetting. While exemplar replay is effective, it raises concerns regarding privacy and storage. Thus, generative replay has emerged as a viable alternative, synthesizing old data using frozen pretrained text-to-image (T2I) models without any extra training. However, we observe that directly mixing synthetic old-class data with real new-class data during incremental training leads to significant performance degradation. This issue stems from a "domain shortcut", where models rely on domain-discriminative features instead of semantic class cues. To address this, we propose DREAM (Domain-Regularized Exemplar-free Alignment Model), which uses a training-free generator to synthesize old-class data and eliminates domain shortcut via subspace rectification and orthogonal projection, while reinforcing semantic alignment through real-anchored prototype regularization. Extensive experiments on 4 datasets demonstrate that DREAM outperforms existing exemplar-free CIL methods and achieves state-of-the-art performance. Our source code is available at https://github.com/Light-ZhangTao/DREAM.
Tao Zhang, Qixuan Fan, Yiyuan Liang +7
Huazhong University of Science and Technology, Wuhan, China · State Key Laboratory of Multispectral Information Intelligent Processing Technology, Wuhan, China · University of Science and Technology of China, Anhui, China +1
Achieving self-evolution in intelligent agents requires the continual accumulation of new knowledge across changing task sequences without forgetting previously acquired abilities. Existing approaches either internalize knowledge by updating model parameters, which induces catastrophic forgetting, or rely on external memory, which fails to genuinely enhance the model's intrinsic capabilities. We propose MoLEM, a generative mixture of latent memory framework based on a dynamic mixture-of-experts (MoE). We treat multiple experts as independent carriers to generate memory. A router selects and weights experts through key-query matching, and the aggregated latent memory is injected into the reasoning process. The base model for reasoning remains entirely frozen, with all experiential knowledge internalized into the additional modules, avoiding catastrophic forgetting. For continual learning, each training stage is paired with a lightweight autoencoder that selects the appropriate routing group at inference, and inputs that match no stage fall back to the pretrained model. Experiments train the framework on continual-learning sequences spanning math, science, and code domains. After training, we evaluate the framework on the corresponding test sets to measure task learning and competence preservation across continual adaptation stages. After the full continual-learning sequence, our method improves the average accuracy by 10.40% over the Vanilla pretrained baseline, while none of the competing methods consistently exceed this baseline across different training orders.
Dianzhi Yu, Vireo Zhang, Hongru Wang +7
The Chinese University of Hong Kong · Nanyang Technological University · University of Edinburgh +2