arXiv Machine Learning

Sequential Pretraining Favors Large Models

The paper investigates why large neural networks outperform smaller ones, focusing on a phenomenon called primacy bias—where early data distributions hinder learning of later ones. It shows that overparameterized models are more robust to this bias, especially during sequential pretraining on heterogeneous data. The authors propose Exposure Therapy, a regularization technique that improves small models’ performance on late data and overall capabilities up to the billion‑parameter scale.

arXiv AI
Oct 26

Beyond Data Schedule: Fast LLM Pretraining on Data Mixtures by Loss-Reweighting

The paper introduces LARE, a method that adjusts domain weights during large language model pretraining by reweighting losses based on running loss statistics, rather than altering data exposure. Experiments on a 1.5B model trained with 240B tokens show that LARE improves performance across five benchmarks, achieving significant gains on GSM8K (+17.06 pp) and MATH (+9.00 pp). The approach demonstrates that balancing loss scales can enhance joint capabilities without increasing domain exposure.

By Jiazheng Li, Huaqing Zhang, Jing Xu, Tianle Cai, Jingzhao Zhang
arXiv AI
Sep 15

Generalization Can Emerge in Tabular Foundation Models From a Single Table

The paper demonstrates that a tabular foundation model can achieve strong generalization using only a single real table for self‑supervised pre‑training, challenging the belief that large synthetic or real datasets are necessary. By systematically pre‑training and evaluating across diverse benchmarks, the authors show that the number and quality of tasks that can be derived from a dataset are critical for downstream performance. This finding suggests that carefully constructed task sets from limited data can enable effective transfer learning in tabular models.

By Junwei Ma, Nour Shaheen, Alex Labach, Amine Mhedhbi, Frank Hutter, Anthony L. Caterini, Valentin Thomas
arXiv AI
Sep 7

Less Data, Faster Training: repeating smaller datasets speeds up learning via sampling biases

The paper titled "Less Data, Faster Training: repeating smaller datasets speeds up learning via sampling biases" examines how training on a smaller dataset with repeated samples can reduce computational cost compared to using a larger dataset. Across various tasks, architectures, and optimizers, this phenomenon cannot be explained by existing theory. The authors attribute the speedup to layer‑wise growth driven by sampling biases, which is more pronounced with smaller datasets, and provide both theoretical analysis and empirical evidence to support this claim.

By Jingwen Liu, Ezra Edelman, Surbhi Goel, Bingbin Liu
arXiv AI
Aug 20

Demystifying Training-Time Augmentation for Data-Constrained Language Model Pretraining

The paper investigates training-time data augmentation as a regularizer for autoregressive language model pretraining in data‑constrained, compute‑abundant settings. It introduces three orthogonal augmentation categories—token‑level noise, sequence permutations, and target offset prediction—and shows through systematic ablations that each category delays overfitting and reduces validation loss, with random token replacement performing best individually. Combining augmentation categories further lowers the minimum validation loss, demonstrating that such augmentations mitigate data inefficiency in autoregressive pretraining.

By Michael K. Chen, Xikun Zhang, Fan Bai, Zhengding Hu, Zhen Wang
arXiv AI
Sep 10

Generating Pretraining Tokens from Organic Data for Data-Bound Scaling

The paper introduces SynPro, a synthetic data generation framework that augments limited organic text for large language model pretraining by applying rephrasing and reformatting operations. SynPro’s generators are optimized with reinforcement learning rewards for quality, faithfulness, and data influence, and are updated continuously as training plateaus. Experiments on 400M, 1.1B, and 2B models show that SynPro can unlock 3.4–5.2× the effective tokens of standard repetition, even outperforming a non‑data‑bound oracle at larger scales.

By Zichun Yu, Chenyan Xiong