Statistical mechanics of extensive-width Bayesian neural networks near interpolation
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Abstract (arXiv)
For three decades statistical mechanics has been providing a framework to analyse neural networks. However, the theoretically tractable models, e.g., perceptrons, random features models and kernel machines, or multi-index models and committee machines with few neurons, remained simple compared to those used in applications. In this paper we help reducing the gap between practical networks and their theoretical understanding through a statistical physics analysis of the supervised learning of a two-layer fully connected network with generic weight distribution and activation function, whose hidden layer is large but remains proportional to the inputs dimension. This makes it more realistic than infinitely wide networks where no feature learning occurs, but also more expressive than narrow ones or with fixed inner weights. We focus on the Bayes-optimal learning in the teacher-student scenario, i.e., with a dataset generated by another network with the same architecture. We operate around interpolation, where the number of trainable parameters and of data are comparable and feature learning emerges. Our analysis uncovers a rich phenomenology with various learning transitions as the number of data increases. In particular, the more strongly the features (i.e., hidden neurons of the target) contribute to the observed responses, the less data is needed to learn them. Moreover, when the data is scarce, the model only learns non-linear combinations of the teacher weights, rather than "specialising" by aligning its weights with the teacher's. Specialisation occurs only when enough data becomes available, but it can be hard to find for practical training algorithms, possibly due to statistical-to-computational~gaps.
Key facts. Cited by 9 papers in the map (data through 7 Oct 2026). Builds on 41 of its 88 references that are in the map. First posted on arXiv 30 May 2025.
Builds on
41 of 88 references.
References · 41
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29 more
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Built on by
Citing papers per year: 2025: 2; 2026: 7.
9 papers.
- 2026There Will Be a Scientific Theory of Deep Learningcited by 21
- 2025Generalization performance of narrow one-hidden layer networks in the teacher-student settingcited by 2
- 2026Statistical Properties of Training & Generalizationcited by 2
- 2026Factual recall in linear associative memories: sharp asymptotics and mechanistic insightscited by 1
- 2026Kernel Renormalization in Bayesian Deep Neural Networks: the Equivalent Wishart Ansatz in the Proportional Regimecited by 1
- 2025Evaluating Double Descent in Machine Learning: Insights from Tree-Based Models Applied to a Genomic Prediction Taskcited by 0
- 2026Sharp feature-learning transitions and Bayes-optimal neural scaling laws in extensive-width networkscited by 0
- 2026Asymmetric Scaling Laws from Sparse Featurescited by 0
- 2026Signal-to-Noise Ratio and Sample Size Govern Representational Alignment in Neural Networkscited by 0
- 2026Statistical Properties of Training & Generalization18 Jun 2026
- 2026Kernel Renormalization in Bayesian Deep Neural Networks: the Equivalent Wishart Ansatz in the Proportional Regime28 May 2026
- 2026Signal-to-Noise Ratio and Sample Size Govern Representational Alignment in Neural Networks26 May 2026
- 2026Asymmetric Scaling Laws from Sparse Features22 May 2026
- 2026Factual recall in linear associative memories: sharp asymptotics and mechanistic insights11 May 2026
- 2026Sharp feature-learning transitions and Bayes-optimal neural scaling laws in extensive-width networks11 May 2026
- 2026There Will Be a Scientific Theory of Deep Learning23 Apr 2026
- 2025Evaluating Double Descent in Machine Learning: Insights from Tree-Based Models Applied to a Genomic Prediction Task22 Sep 2025
- 2025Generalization performance of narrow one-hidden layer networks in the teacher-student setting1 Jul 2025