Toward Understanding In-context vs. In-weight Learning

Fuente: arXiv
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Hauptverfasser: Chan, Bryan, Chen, Xinyi, György, András, Schuurmans, Dale
Format: Preprint
Veröffentlicht: 2024
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author Chan, Bryan
Chen, Xinyi
György, András
Schuurmans, Dale
author_facet Chan, Bryan
Chen, Xinyi
György, András
Schuurmans, Dale
contents It has recently been demonstrated empirically that in-context learning emerges in transformers when certain distributional properties are present in the training data, but this ability can also diminish upon further training. We provide a new theoretical understanding of these phenomena by identifying simplified distributional properties that give rise to the emergence and eventual disappearance of in-context learning. We do so by first analyzing a simplified model that uses a gating mechanism to choose between an in-weight and an in-context predictor. Through a combination of a generalization error and regret analysis we identify conditions where in-context and in-weight learning emerge. These theoretical findings are then corroborated experimentally by comparing the behaviour of a full transformer on the simplified distributions to that of the stylized model, demonstrating aligned results. We then extend the study to a full large language model, showing how fine-tuning on various collections of natural language prompts can elicit similar in-context and in-weight learning behaviour.
format Preprint
id arxiv_https___arxiv_org_abs_2410_23042
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Toward Understanding In-context vs. In-weight Learning
Chan, Bryan
Chen, Xinyi
György, András
Schuurmans, Dale
Machine Learning
It has recently been demonstrated empirically that in-context learning emerges in transformers when certain distributional properties are present in the training data, but this ability can also diminish upon further training. We provide a new theoretical understanding of these phenomena by identifying simplified distributional properties that give rise to the emergence and eventual disappearance of in-context learning. We do so by first analyzing a simplified model that uses a gating mechanism to choose between an in-weight and an in-context predictor. Through a combination of a generalization error and regret analysis we identify conditions where in-context and in-weight learning emerge. These theoretical findings are then corroborated experimentally by comparing the behaviour of a full transformer on the simplified distributions to that of the stylized model, demonstrating aligned results. We then extend the study to a full large language model, showing how fine-tuning on various collections of natural language prompts can elicit similar in-context and in-weight learning behaviour.
title Toward Understanding In-context vs. In-weight Learning
topic Machine Learning
url https://arxiv.org/abs/2410.23042