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Bibliographic Details
Main Authors: Stern, Uri, Yaacoby, Tomer, Weinshall, Daphna
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2412.12968
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author Stern, Uri
Yaacoby, Tomer
Weinshall, Daphna
author_facet Stern, Uri
Yaacoby, Tomer
Weinshall, Daphna
contents The infrequent occurrence of overfitting in deep neural networks is perplexing: contrary to theoretical expectations, increasing model size often enhances performance in practice. But what if overfitting does occur, though restricted to specific sub-regions of the data space? In this work, we propose a novel score that captures the forgetting rate of deep models on validation data. We posit that this score quantifies local overfitting: a decline in performance confined to certain regions of the data space. We then show empirically that local overfitting occurs regardless of the presence of traditional overfitting. Using the framework of deep over-parametrized linear models, we offer a certain theoretical characterization of forgotten knowledge, and show that it correlates with knowledge forgotten by real deep models. Finally, we devise a new ensemble method that aims to recover forgotten knowledge, relying solely on the training history of a single network. When combined with self-distillation, this method enhances the performance of any trained model without adding inference costs. Extensive empirical evaluations demonstrate the efficacy of our method across multiple datasets, contemporary neural network architectures, and training protocols.
format Preprint
id arxiv_https___arxiv_org_abs_2412_12968
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On Local Overfitting and Forgetting in Deep Neural Networks
Stern, Uri
Yaacoby, Tomer
Weinshall, Daphna
Machine Learning
The infrequent occurrence of overfitting in deep neural networks is perplexing: contrary to theoretical expectations, increasing model size often enhances performance in practice. But what if overfitting does occur, though restricted to specific sub-regions of the data space? In this work, we propose a novel score that captures the forgetting rate of deep models on validation data. We posit that this score quantifies local overfitting: a decline in performance confined to certain regions of the data space. We then show empirically that local overfitting occurs regardless of the presence of traditional overfitting. Using the framework of deep over-parametrized linear models, we offer a certain theoretical characterization of forgotten knowledge, and show that it correlates with knowledge forgotten by real deep models. Finally, we devise a new ensemble method that aims to recover forgotten knowledge, relying solely on the training history of a single network. When combined with self-distillation, this method enhances the performance of any trained model without adding inference costs. Extensive empirical evaluations demonstrate the efficacy of our method across multiple datasets, contemporary neural network architectures, and training protocols.
title On Local Overfitting and Forgetting in Deep Neural Networks
topic Machine Learning
url https://arxiv.org/abs/2412.12968