Pre-training isn’t bitter enough
Summary
Value-based pre-training with downstream feedback (V-pretraining) introduces a novel approach to foundation model training by making the self-supervised task objective learnable. Unlike standard pre-training, which fixes the task construction rule, V-pretraining employs a lightweight task designer that uses a small set of verifiable downstream examples to dynamically construct self-supervised tasks. The core foundation model, or learner, continues to update solely through self-supervised loss on unlabeled data, while the designer learns to create tasks whose gradients align with downstream performance. This indirect feedback mechanism was demonstrated in language models, where V-pretraining improved GSM8K Pass@1 for Qwen2.5-0.5B from 22.20 to 29.60 and Qwen1.5-4B from 56.48±1.56 to 58.98±1.03. In vision, DINOv3-ViT-L saw ADE20K mIoU increase from 51.33 to 52.47 and NYUv2 RMSE improve from 0.5752 to 0.5522.
Key takeaway
For Machine Learning Engineers optimizing foundation model pre-training, V-pretraining offers a path to more effectively align self-supervised objectives with downstream goals. You should consider implementing a learnable task designer to dynamically construct pre-training tasks, using a small set of downstream examples to guide this process indirectly. This approach can yield significant performance gains, as demonstrated by improved GSM8K Pass@1 and vision metrics, without directly supervising the learner.
Key insights
V-pretraining makes self-supervised task construction learnable via indirect downstream feedback, improving foundation model performance.
Principles
- The "Bitter Lesson" extends to learning what to predict, not just how to learn.
- Separating learner and task designer enables indirect downstream feedback.
- Aligning self-supervised gradients with downstream gradients improves utility.
Method
V-pretraining trains a task designer to construct self-supervised tasks (e.g., soft target distributions, view augmentations) whose resulting learner gradients align with gradients from a small downstream feedback batch. The learner then updates self-supervisely.
In practice
- Apply adaptive top-K soft target construction for language models.
- Modify DINO-style view construction for vision models.
- Use small downstream feedback batches to guide pre-training.
Topics
- V-pretraining
- Foundation Models
- Self-supervised Learning
- Task Design
- Downstream Alignment
- Gradient Alignment
Best for: Research Scientist, AI Scientist, Machine Learning Engineer
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Editorial summary, takeaway, and curation by AIssential. Original article published by ΑΙhub.