Dynamics of Transient Structure in In-Context Linear Regression Transformers

Fuente: arXiv
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Auteurs principaux: Carroll, Liam, Hoogland, Jesse, Farrugia-Roberts, Matthew, Murfet, Daniel
Format: Preprint
Publié: 2025
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author Carroll, Liam
Hoogland, Jesse
Farrugia-Roberts, Matthew
Murfet, Daniel
author_facet Carroll, Liam
Hoogland, Jesse
Farrugia-Roberts, Matthew
Murfet, Daniel
contents Modern deep neural networks display striking examples of rich internal computational structure. Uncovering principles governing the development of such structure is a priority for the science of deep learning. In this paper, we explore the transient ridge phenomenon: when transformers are trained on in-context linear regression tasks with intermediate task diversity, they initially behave like ridge regression before specializing to the tasks in their training distribution. This transition from a general solution to a specialized solution is revealed by joint trajectory principal component analysis. Further, we draw on the theory of Bayesian internal model selection to suggest a general explanation for the phenomena of transient structure in transformers, based on an evolving tradeoff between loss and complexity. We empirically validate this explanation by measuring the model complexity of our transformers as defined by the local learning coefficient.
format Preprint
id arxiv_https___arxiv_org_abs_2501_17745
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Dynamics of Transient Structure in In-Context Linear Regression Transformers
Carroll, Liam
Hoogland, Jesse
Farrugia-Roberts, Matthew
Murfet, Daniel
Machine Learning
Modern deep neural networks display striking examples of rich internal computational structure. Uncovering principles governing the development of such structure is a priority for the science of deep learning. In this paper, we explore the transient ridge phenomenon: when transformers are trained on in-context linear regression tasks with intermediate task diversity, they initially behave like ridge regression before specializing to the tasks in their training distribution. This transition from a general solution to a specialized solution is revealed by joint trajectory principal component analysis. Further, we draw on the theory of Bayesian internal model selection to suggest a general explanation for the phenomena of transient structure in transformers, based on an evolving tradeoff between loss and complexity. We empirically validate this explanation by measuring the model complexity of our transformers as defined by the local learning coefficient.
title Dynamics of Transient Structure in In-Context Linear Regression Transformers
topic Machine Learning
url https://arxiv.org/abs/2501.17745