Extreme Memorization via Scale of Initialization
Authors: Harsh Mehta, Ashok Cutkosky, Behnam Neyshabur
Venue: ICLR 2021 Poster
Keywords: Scale of initialization, Memorization, Overfitting, Generalization, Generalization Measure, Understanding Deep Learning
Abstract: We construct an experimental setup in which changing the scale of initialization strongly impacts the implicit regularization induced by SGD, interpolating from good generalization performance to completely memorizing the training set while making little progress on the test set. Moreover, we find that the extent and manner in which generalization ability is affected depends on the activation and loss function used, with sin activation being the most extreme. In the case of the homogeneous ReLU activation, we show that this behavior can be attributed to the loss function. Our empirical investigation reveals that increasing the scale of initialization correlates with misalignment of representations and gradients across examples in the same class. This insight allows us to device an alignment measure over gradients and representations which can capture this phenomenon. We demonstrate that our alignment measure correlates with generalization of deep models trained on image classification tasks.