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Main Authors: Kang, Katie, Setlur, Amrith, Tomlin, Claire, Levine, Sergey
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2310.00873
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author Kang, Katie
Setlur, Amrith
Tomlin, Claire
Levine, Sergey
author_facet Kang, Katie
Setlur, Amrith
Tomlin, Claire
Levine, Sergey
contents Conventional wisdom suggests that neural network predictions tend to be unpredictable and overconfident when faced with out-of-distribution (OOD) inputs. Our work reassesses this assumption for neural networks with high-dimensional inputs. Rather than extrapolating in arbitrary ways, we observe that neural network predictions often tend towards a constant value as input data becomes increasingly OOD. Moreover, we find that this value often closely approximates the optimal constant solution (OCS), i.e., the prediction that minimizes the average loss over the training data without observing the input. We present results showing this phenomenon across 8 datasets with different distributional shifts (including CIFAR10-C and ImageNet-R, S), different loss functions (cross entropy, MSE, and Gaussian NLL), and different architectures (CNNs and transformers). Furthermore, we present an explanation for this behavior, which we first validate empirically and then study theoretically in a simplified setting involving deep homogeneous networks with ReLU activations. Finally, we show how one can leverage our insights in practice to enable risk-sensitive decision-making in the presence of OOD inputs.
format Preprint
id arxiv_https___arxiv_org_abs_2310_00873
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Deep Neural Networks Tend To Extrapolate Predictably
Kang, Katie
Setlur, Amrith
Tomlin, Claire
Levine, Sergey
Machine Learning
Conventional wisdom suggests that neural network predictions tend to be unpredictable and overconfident when faced with out-of-distribution (OOD) inputs. Our work reassesses this assumption for neural networks with high-dimensional inputs. Rather than extrapolating in arbitrary ways, we observe that neural network predictions often tend towards a constant value as input data becomes increasingly OOD. Moreover, we find that this value often closely approximates the optimal constant solution (OCS), i.e., the prediction that minimizes the average loss over the training data without observing the input. We present results showing this phenomenon across 8 datasets with different distributional shifts (including CIFAR10-C and ImageNet-R, S), different loss functions (cross entropy, MSE, and Gaussian NLL), and different architectures (CNNs and transformers). Furthermore, we present an explanation for this behavior, which we first validate empirically and then study theoretically in a simplified setting involving deep homogeneous networks with ReLU activations. Finally, we show how one can leverage our insights in practice to enable risk-sensitive decision-making in the presence of OOD inputs.
title Deep Neural Networks Tend To Extrapolate Predictably
topic Machine Learning
url https://arxiv.org/abs/2310.00873