Linear Representation Transferability Hypothesis: Leveraging Small Models to Steer Large Models

Fuente: arXiv
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Hauptverfasser: Bello, Femi, Das, Anubrata, Zeng, Fanzhi, Yin, Fangcong, Leqi, Liu
Format: Preprint
Veröffentlicht: 2025
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author Bello, Femi
Das, Anubrata
Zeng, Fanzhi
Yin, Fangcong
Leqi, Liu
author_facet Bello, Femi
Das, Anubrata
Zeng, Fanzhi
Yin, Fangcong
Leqi, Liu
contents It has been hypothesized that neural networks with similar architectures trained on similar data learn shared representations relevant to the learning task. We build on this idea by extending the conceptual framework where representations learned across models trained on the same data can be expressed as linear combinations of a \emph{universal} set of basis features. These basis features underlie the learning task itself and remain consistent across models, regardless of scale. From this framework, we propose the \textbf{Linear Representation Transferability (LRT)} Hypothesis -- that there exists an affine transformation between the representation spaces of different models. To test this hypothesis, we learn affine mappings between the hidden states of models of different sizes and evaluate whether steering vectors -- directions in hidden state space associated with specific model behaviors -- retain their semantic effect when transferred from small to large language models using the learned mappings. We find strong empirical evidence that such affine mappings can preserve steering behaviors. These findings suggest that representations learned by small models can be used to guide the behavior of large models, and that the LRT hypothesis may be a promising direction on understanding representation alignment across model scales.
format Preprint
id arxiv_https___arxiv_org_abs_2506_00653
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Linear Representation Transferability Hypothesis: Leveraging Small Models to Steer Large Models
Bello, Femi
Das, Anubrata
Zeng, Fanzhi
Yin, Fangcong
Leqi, Liu
Machine Learning
Artificial Intelligence
Computation and Language
It has been hypothesized that neural networks with similar architectures trained on similar data learn shared representations relevant to the learning task. We build on this idea by extending the conceptual framework where representations learned across models trained on the same data can be expressed as linear combinations of a \emph{universal} set of basis features. These basis features underlie the learning task itself and remain consistent across models, regardless of scale. From this framework, we propose the \textbf{Linear Representation Transferability (LRT)} Hypothesis -- that there exists an affine transformation between the representation spaces of different models. To test this hypothesis, we learn affine mappings between the hidden states of models of different sizes and evaluate whether steering vectors -- directions in hidden state space associated with specific model behaviors -- retain their semantic effect when transferred from small to large language models using the learned mappings. We find strong empirical evidence that such affine mappings can preserve steering behaviors. These findings suggest that representations learned by small models can be used to guide the behavior of large models, and that the LRT hypothesis may be a promising direction on understanding representation alignment across model scales.
title Linear Representation Transferability Hypothesis: Leveraging Small Models to Steer Large Models
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2506.00653