---
title: "What Improves During Pretraining? Tracking Knowledge Acquisition with Point-in-Time Models"
source: "arXiv AI/CL/LG（论文）"
source_tier: "t2"
url: "https://arxiv.org/abs/2610.37631v1"
permalink: "https://feed.astralor.com/items/itm_ec76c0ab38acbf6e99d8f7c0"
published: "2026-10-27T17:52:38.000Z"
score: 54
channel: "finance"
tags: ["RAG","What Improves During","Pretraining","Tracking Knowledge Acquisition","Point-in-Time Models Language","Rec","Language"]
---

# What Improves During Pretraining? Tracking Knowledge Acquisition with Point-in-Time Models

## At a glance

Language models pretrained on web corpora collected over multiple years learn both general and domain-specific knowledge. How these different kinds of knowledge are learned as pretraining progresses remains unclear. Rec…

## Key points

- Language models pretrained on web corpora collected over multiple years learn both general and domain-specific knowledge.
- How these different kinds of knowledge are learned as pretraining progresses remains unclear.
- Recent point-in-time models trained on web snapshots from different years provide a way to probe how knowledge prevalence varies over time.

## Full text

Language models pretrained on web corpora collected over multiple years learn both general and domain-specific knowledge. How these different kinds of knowledge are learned as pretraining progresses remains unclear. Recent point-in-time models trained on web snapshots from different years provide a way to probe how knowledge prevalence varies over time. Using these models, we propose a temporal variability score (TVS), defined as the coefficient of variation of an item's negative log-likelihood across models. A higher score suggests that the knowledge may be less consistently represented across years of web text. We evaluate six benchmarks covering diverse topics using six models from multiple open-source model families. We find that low- and high-TVS items are learned similarly early in training, but high-TVS items improve faster later on. At the end of the pretraining run, high-TVS items outperform low-TVS items in 34 of 36 model-benchmark settings, with an average advantage of 7.3 points of chance-normalized accuracy. This pattern is most robust on knowledge-intensive tasks, even when comparing items of similar difficulty. Our findings reveal differences in how knowledge is learned over the course of pretraining, with temporal variability providing a diagnostic of these learning dynamics beyond aggregate benchmark scores.

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