Distilled Pretraining: A modern lens of Data, In-Context Learning and Test-Time Scaling

Fuente: arXiv
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Main Authors: Goyal, Sachin, Lopez-Paz, David, Ahuja, Kartik
Format: Preprint
Published: 2025
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author Goyal, Sachin
Lopez-Paz, David
Ahuja, Kartik
author_facet Goyal, Sachin
Lopez-Paz, David
Ahuja, Kartik
contents In the past year, distillation has seen a renewed prominence in large language model (LLM) pretraining, exemplified by the Llama-3.2 and Gemma model families. While distillation has historically been shown to improve statistical modeling, its effects on new paradigms that are key to modern LLMs, such as test-time scaling and in-context learning, remain underexplored. In this work, we make three main contributions. First, we show that pretraining with distillation yields models that exhibit remarkably better test-time scaling. Second, we observe that this benefit comes with a trade-off: distillation impairs in-context learning capabilities, particularly the one modeled via induction heads. Third, to demystify these findings, we study distilled pretraining in a sandbox of a bigram model, which helps us isolate the common principal factor behind our observations. Finally, using these insights, we shed light on various design choices for pretraining that should help practitioners going forward.
format Preprint
id arxiv_https___arxiv_org_abs_2509_01649
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Distilled Pretraining: A modern lens of Data, In-Context Learning and Test-Time Scaling
Goyal, Sachin
Lopez-Paz, David
Ahuja, Kartik
Machine Learning
In the past year, distillation has seen a renewed prominence in large language model (LLM) pretraining, exemplified by the Llama-3.2 and Gemma model families. While distillation has historically been shown to improve statistical modeling, its effects on new paradigms that are key to modern LLMs, such as test-time scaling and in-context learning, remain underexplored. In this work, we make three main contributions. First, we show that pretraining with distillation yields models that exhibit remarkably better test-time scaling. Second, we observe that this benefit comes with a trade-off: distillation impairs in-context learning capabilities, particularly the one modeled via induction heads. Third, to demystify these findings, we study distilled pretraining in a sandbox of a bigram model, which helps us isolate the common principal factor behind our observations. Finally, using these insights, we shed light on various design choices for pretraining that should help practitioners going forward.
title Distilled Pretraining: A modern lens of Data, In-Context Learning and Test-Time Scaling
topic Machine Learning
url https://arxiv.org/abs/2509.01649