Exploring the Stability Gap in Continual Learning: The Role of the Classification Head

Fuente: arXiv
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Autori principali: Łapacz, Wojciech, Marczak, Daniel, Szatkowski, Filip, Trzciński, Tomasz
Natura: Preprint
Pubblicazione: 2024
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author Łapacz, Wojciech
Marczak, Daniel
Szatkowski, Filip
Trzciński, Tomasz
author_facet Łapacz, Wojciech
Marczak, Daniel
Szatkowski, Filip
Trzciński, Tomasz
contents Continual learning (CL) has emerged as a critical area in machine learning, enabling neural networks to learn from evolving data distributions while mitigating catastrophic forgetting. However, recent research has identified the stability gap -- a phenomenon where models initially lose performance on previously learned tasks before partially recovering during training. Such learning dynamics are contradictory to the intuitive understanding of stability in continual learning where one would expect the performance to degrade gradually instead of rapidly decreasing and then partially recovering later. To better understand and alleviate the stability gap, we investigate it at different levels of the neural network architecture, particularly focusing on the role of the classification head. We introduce the nearest-mean classifier (NMC) as a tool to attribute the influence of the backbone and the classification head on the stability gap. Our experiments demonstrate that NMC not only improves final performance, but also significantly enhances training stability across various continual learning benchmarks, including CIFAR100, ImageNet100, CUB-200, and FGVC Aircrafts. Moreover, we find that NMC also reduces task-recency bias. Our analysis provides new insights into the stability gap and suggests that the primary contributor to this phenomenon is the linear head, rather than the insufficient representation learning.
format Preprint
id arxiv_https___arxiv_org_abs_2411_04723
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Exploring the Stability Gap in Continual Learning: The Role of the Classification Head
Łapacz, Wojciech
Marczak, Daniel
Szatkowski, Filip
Trzciński, Tomasz
Machine Learning
Artificial Intelligence
Computer Vision and Pattern Recognition
Continual learning (CL) has emerged as a critical area in machine learning, enabling neural networks to learn from evolving data distributions while mitigating catastrophic forgetting. However, recent research has identified the stability gap -- a phenomenon where models initially lose performance on previously learned tasks before partially recovering during training. Such learning dynamics are contradictory to the intuitive understanding of stability in continual learning where one would expect the performance to degrade gradually instead of rapidly decreasing and then partially recovering later. To better understand and alleviate the stability gap, we investigate it at different levels of the neural network architecture, particularly focusing on the role of the classification head. We introduce the nearest-mean classifier (NMC) as a tool to attribute the influence of the backbone and the classification head on the stability gap. Our experiments demonstrate that NMC not only improves final performance, but also significantly enhances training stability across various continual learning benchmarks, including CIFAR100, ImageNet100, CUB-200, and FGVC Aircrafts. Moreover, we find that NMC also reduces task-recency bias. Our analysis provides new insights into the stability gap and suggests that the primary contributor to this phenomenon is the linear head, rather than the insufficient representation learning.
title Exploring the Stability Gap in Continual Learning: The Role of the Classification Head
topic Machine Learning
Artificial Intelligence
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2411.04723