Weak-to-Strong Generalization Even in Random Feature Networks, Provably

Fuente: arXiv
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Main Authors: Medvedev, Marko, Lyu, Kaifeng, Yu, Dingli, Arora, Sanjeev, Li, Zhiyuan, Srebro, Nathan
Format: Preprint
Published: 2025
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author Medvedev, Marko
Lyu, Kaifeng
Yu, Dingli
Arora, Sanjeev
Li, Zhiyuan
Srebro, Nathan
author_facet Medvedev, Marko
Lyu, Kaifeng
Yu, Dingli
Arora, Sanjeev
Li, Zhiyuan
Srebro, Nathan
contents Weak-to-Strong Generalization (Burns et al., 2024) is the phenomenon whereby a strong student, say GPT-4, learns a task from a weak teacher, say GPT-2, and ends up significantly outperforming the teacher. We show that this phenomenon does not require a strong learner like GPT-4. We consider student and teacher that are random feature models, described by two-layer networks with a random and fixed bottom layer and a trained top layer. A "weak" teacher, with a small number of units (i.e. random features), is trained on the population, and a "strong" student, with a much larger number of units (i.e. random features), is trained only on labels generated by the weak teacher. We demonstrate, prove, and understand how the student can outperform the teacher, even though trained only on data labeled by the teacher. We also explain how such weak-to-strong generalization is enabled by early stopping. Importantly, we also show the quantitative limits of weak-to-strong generalization in this model.
format Preprint
id arxiv_https___arxiv_org_abs_2503_02877
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Weak-to-Strong Generalization Even in Random Feature Networks, Provably
Medvedev, Marko
Lyu, Kaifeng
Yu, Dingli
Arora, Sanjeev
Li, Zhiyuan
Srebro, Nathan
Machine Learning
Weak-to-Strong Generalization (Burns et al., 2024) is the phenomenon whereby a strong student, say GPT-4, learns a task from a weak teacher, say GPT-2, and ends up significantly outperforming the teacher. We show that this phenomenon does not require a strong learner like GPT-4. We consider student and teacher that are random feature models, described by two-layer networks with a random and fixed bottom layer and a trained top layer. A "weak" teacher, with a small number of units (i.e. random features), is trained on the population, and a "strong" student, with a much larger number of units (i.e. random features), is trained only on labels generated by the weak teacher. We demonstrate, prove, and understand how the student can outperform the teacher, even though trained only on data labeled by the teacher. We also explain how such weak-to-strong generalization is enabled by early stopping. Importantly, we also show the quantitative limits of weak-to-strong generalization in this model.
title Weak-to-Strong Generalization Even in Random Feature Networks, Provably
topic Machine Learning
url https://arxiv.org/abs/2503.02877