Spurious Forgetting in Continual Learning of Language Models

Fuente: arXiv
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Auteurs principaux: Zheng, Junhao, Cai, Xidi, Qiu, Shengjie, Ma, Qianli
Format: Preprint
Publié: 2025
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author Zheng, Junhao
Cai, Xidi
Qiu, Shengjie
Ma, Qianli
author_facet Zheng, Junhao
Cai, Xidi
Qiu, Shengjie
Ma, Qianli
contents Recent advancements in large language models (LLMs) reveal a perplexing phenomenon in continual learning: despite extensive training, models experience significant performance declines, raising questions about task alignment and underlying knowledge retention. This study first explores the concept of "spurious forgetting", proposing that such performance drops often reflect a decline in task alignment rather than true knowledge loss. Through controlled experiments with a synthesized dataset, we investigate the dynamics of model performance during the initial training phases of new tasks, discovering that early optimization steps can disrupt previously established task alignments. Our theoretical analysis connects these shifts to orthogonal updates in model weights, providing a robust framework for understanding this behavior. Ultimately, we introduce a Freezing strategy that fix the bottom layers of the model, leading to substantial improvements in four continual learning scenarios. Our findings underscore the critical distinction between task alignment and knowledge retention, paving the way for more effective strategies in continual learning.
format Preprint
id arxiv_https___arxiv_org_abs_2501_13453
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spurious Forgetting in Continual Learning of Language Models
Zheng, Junhao
Cai, Xidi
Qiu, Shengjie
Ma, Qianli
Machine Learning
Recent advancements in large language models (LLMs) reveal a perplexing phenomenon in continual learning: despite extensive training, models experience significant performance declines, raising questions about task alignment and underlying knowledge retention. This study first explores the concept of "spurious forgetting", proposing that such performance drops often reflect a decline in task alignment rather than true knowledge loss. Through controlled experiments with a synthesized dataset, we investigate the dynamics of model performance during the initial training phases of new tasks, discovering that early optimization steps can disrupt previously established task alignments. Our theoretical analysis connects these shifts to orthogonal updates in model weights, providing a robust framework for understanding this behavior. Ultimately, we introduce a Freezing strategy that fix the bottom layers of the model, leading to substantial improvements in four continual learning scenarios. Our findings underscore the critical distinction between task alignment and knowledge retention, paving the way for more effective strategies in continual learning.
title Spurious Forgetting in Continual Learning of Language Models
topic Machine Learning
url https://arxiv.org/abs/2501.13453