Superposition Yields Robust Neural Scaling

Fuente: arXiv
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Main Authors: Liu, Yizhou, Liu, Ziming, Gore, Jeff
Format: Preprint
Published: 2025
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author Liu, Yizhou
Liu, Ziming
Gore, Jeff
author_facet Liu, Yizhou
Liu, Ziming
Gore, Jeff
contents The success of today's large language models (LLMs) depends on the observation that larger models perform better. However, the origin of this neural scaling law, that loss decreases as a power law with model size, remains unclear. We propose that representation superposition, meaning that LLMs represent more features than they have dimensions, can be a key contributor to loss and cause neural scaling. Based on Anthropic's toy model, we use weight decay to control the degree of superposition, allowing us to systematically study how loss scales with model size. When superposition is weak, the loss follows a power law only if data feature frequencies are power-law distributed. In contrast, under strong superposition, the loss generically scales inversely with model dimension across a broad class of frequency distributions, due to geometric overlaps between representation vectors. We confirmed that open-sourced LLMs operate in the strong superposition regime and have loss scaling inversely with model dimension, and that the Chinchilla scaling laws are also consistent with this behavior. Our results identify representation superposition as a central driver of neural scaling laws, providing insights into questions like when neural scaling laws can be improved and when they will break down.
format Preprint
id arxiv_https___arxiv_org_abs_2505_10465
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Superposition Yields Robust Neural Scaling
Liu, Yizhou
Liu, Ziming
Gore, Jeff
Machine Learning
Artificial Intelligence
Computation and Language
The success of today's large language models (LLMs) depends on the observation that larger models perform better. However, the origin of this neural scaling law, that loss decreases as a power law with model size, remains unclear. We propose that representation superposition, meaning that LLMs represent more features than they have dimensions, can be a key contributor to loss and cause neural scaling. Based on Anthropic's toy model, we use weight decay to control the degree of superposition, allowing us to systematically study how loss scales with model size. When superposition is weak, the loss follows a power law only if data feature frequencies are power-law distributed. In contrast, under strong superposition, the loss generically scales inversely with model dimension across a broad class of frequency distributions, due to geometric overlaps between representation vectors. We confirmed that open-sourced LLMs operate in the strong superposition regime and have loss scaling inversely with model dimension, and that the Chinchilla scaling laws are also consistent with this behavior. Our results identify representation superposition as a central driver of neural scaling laws, providing insights into questions like when neural scaling laws can be improved and when they will break down.
title Superposition Yields Robust Neural Scaling
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2505.10465