MDL-AE: Investigating the trade-off between compressive fidelity and discriminative utility in self-supervised learning
Bibliographic record
Abstract
Current paradigms in Self-Supervised Learning (SSL) achieve state-of-the-art results through complex, heuristic-driven pretext tasks like contrastive learning or masked image modeling. We propose a departure from these heuristics by reframing SSL through the fundamental Minimum Description Length (MDL) principle. We introduce the MDL-Autoencoder (MDL-AE), learning visual representations by optimizing a Vector Quantized Variational AutoEncoder (VQ-VAE)-based objective for efficient, discrete compression of visual data. Through rigorous experiments on the Canadian Institute for Advanced Research 10 (CIFAR-10), we demonstrate that this compression-driven objective learns a rich vocabulary of local visual concepts. However, we uncover a critical architectural insight: despite learning a visibly superior, higher-fidelity vocabulary, a more powerful tokenizer fails to improve downstream performance. We show that the MDL-AE learns holistic object parts rather than generic, composable primitives. Consequently, a sophisticated Vision Transformer (ViT) head consistently fails to outperform a simple linear probe on the flattened feature map. This architectural mismatch reveals that the nature of the learned representation dictates the optimal downstream architecture. To validate this, we demonstrate that a dedicated self-supervised alignment task, based on Masked Autoencoding of the discrete tokens, resolves this mismatch and dramatically improves performance, bridging the gap between generative fidelity and discriminative utility. Our work provides a compelling case study on co-designing objectives and downstream architectures.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.005 | 0.016 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.001 | 0.003 |
| Open science | 0.002 | 0.003 |
| Research integrity | 0.002 | 0.003 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".