Graph Neural Networks Use Graphs When They Shouldn't

Fuente: arXiv
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Main Authors: Bechler-Speicher, Maya, Amos, Ido, Gilad-Bachrach, Ran, Globerson, Amir
Format: Preprint
Published: 2023
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author Bechler-Speicher, Maya
Amos, Ido
Gilad-Bachrach, Ran
Globerson, Amir
author_facet Bechler-Speicher, Maya
Amos, Ido
Gilad-Bachrach, Ran
Globerson, Amir
contents Predictions over graphs play a crucial role in various domains, including social networks and medicine. Graph Neural Networks (GNNs) have emerged as the dominant approach for learning on graph data. Although a graph-structure is provided as input to the GNN, in some cases the best solution can be obtained by ignoring it. While GNNs have the ability to ignore the graph- structure in such cases, it is not clear that they will. In this work, we show that GNNs actually tend to overfit the given graph-structure. Namely, they use it even when a better solution can be obtained by ignoring it. We analyze the implicit bias of gradient-descent learning of GNNs and prove that when the ground truth function does not use the graphs, GNNs are not guaranteed to learn a solution that ignores the graph, even with infinite data. We examine this phenomenon with respect to different graph distributions and find that regular graphs are more robust to this over-fitting. We also prove that within the family of regular graphs, GNNs are guaranteed to extrapolate when learning with gradient descent. Finally, based on our empirical and theoretical findings, we demonstrate on real-data how regular graphs can be leveraged to reduce graph overfitting and enhance performance.
format Preprint
id arxiv_https___arxiv_org_abs_2309_04332
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Graph Neural Networks Use Graphs When They Shouldn't
Bechler-Speicher, Maya
Amos, Ido
Gilad-Bachrach, Ran
Globerson, Amir
Machine Learning
Artificial Intelligence
Predictions over graphs play a crucial role in various domains, including social networks and medicine. Graph Neural Networks (GNNs) have emerged as the dominant approach for learning on graph data. Although a graph-structure is provided as input to the GNN, in some cases the best solution can be obtained by ignoring it. While GNNs have the ability to ignore the graph- structure in such cases, it is not clear that they will. In this work, we show that GNNs actually tend to overfit the given graph-structure. Namely, they use it even when a better solution can be obtained by ignoring it. We analyze the implicit bias of gradient-descent learning of GNNs and prove that when the ground truth function does not use the graphs, GNNs are not guaranteed to learn a solution that ignores the graph, even with infinite data. We examine this phenomenon with respect to different graph distributions and find that regular graphs are more robust to this over-fitting. We also prove that within the family of regular graphs, GNNs are guaranteed to extrapolate when learning with gradient descent. Finally, based on our empirical and theoretical findings, we demonstrate on real-data how regular graphs can be leveraged to reduce graph overfitting and enhance performance.
title Graph Neural Networks Use Graphs When They Shouldn't
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2309.04332