Title
The Implicit Bias of Depth: How Incremental Learning Drives Generalization
Abstract
A leading hypothesis for the surprising generalization of neural networks is that the dynamics of gradient descent bias the model towards simple solutions, by searching through the solution space in an incremental order of complexity. We formally define the notion of incremental learning dynamics and derive the conditions on depth and initialization for which this phenomenon arises in deep linear models. Our main theoretical contribution is a dynamical depth separation result, proving that while shallow models can exhibit incremental learning dynamics, they require the initialization to be exponentially small for these dynamics to present themselves. However, once the model becomes deeper, the dependence becomes polynomial and incremental learning can arise in more natural settings. We complement our theoretical findings by experimenting with deep matrix sensing, quadratic neural networks and with binary classification using diagonal and convolutional linear networks, showing all of these models exhibit incremental learning.
Year
Venue
Keywords
2020
ICLR
gradient flow, gradient descent, implicit regularization, implicit bias, generalization, optimization, quadratic network, matrix sensing
DocType
Citations 
PageRank 
Conference
0
0.34
References 
Authors
14
3
Name
Order
Citations
PageRank
Daniel Gissin100.34
Shai Shalev-Shwartz23681276.32
Amit Daniely321620.92