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Main Authors: Nielsen, Beatrix M. G., Marconato, Emanuele, Dittadi, Andrea, Gresele, Luigi
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2506.03784
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author Nielsen, Beatrix M. G.
Marconato, Emanuele
Dittadi, Andrea
Gresele, Luigi
author_facet Nielsen, Beatrix M. G.
Marconato, Emanuele
Dittadi, Andrea
Gresele, Luigi
contents When and why representations learned by different deep neural networks are similar is an active research topic. We choose to address these questions from the perspective of identifiability theory, which suggests that a measure of representational similarity should be invariant to transformations that leave the model distribution unchanged. Focusing on a model family which includes several popular pre-training approaches, e.g., autoregressive language models, we explore when models which generate distributions that are close have similar representations. We prove that a small Kullback--Leibler divergence between the model distributions does not guarantee that the corresponding representations are similar. This has the important corollary that models with near-maximum data likelihood can still learn dissimilar representations -- a phenomenon mirrored in our experiments with models trained on CIFAR-10. We then define a distributional distance for which closeness implies representational similarity, and in synthetic experiments, we find that wider networks learn distributions which are closer with respect to our distance and have more similar representations. Our results thus clarify the link between closeness in distribution and representational similarity.
format Preprint
id arxiv_https___arxiv_org_abs_2506_03784
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle When Does Closeness in Distribution Imply Representational Similarity? An Identifiability Perspective
Nielsen, Beatrix M. G.
Marconato, Emanuele
Dittadi, Andrea
Gresele, Luigi
Machine Learning
Artificial Intelligence
When and why representations learned by different deep neural networks are similar is an active research topic. We choose to address these questions from the perspective of identifiability theory, which suggests that a measure of representational similarity should be invariant to transformations that leave the model distribution unchanged. Focusing on a model family which includes several popular pre-training approaches, e.g., autoregressive language models, we explore when models which generate distributions that are close have similar representations. We prove that a small Kullback--Leibler divergence between the model distributions does not guarantee that the corresponding representations are similar. This has the important corollary that models with near-maximum data likelihood can still learn dissimilar representations -- a phenomenon mirrored in our experiments with models trained on CIFAR-10. We then define a distributional distance for which closeness implies representational similarity, and in synthetic experiments, we find that wider networks learn distributions which are closer with respect to our distance and have more similar representations. Our results thus clarify the link between closeness in distribution and representational similarity.
title When Does Closeness in Distribution Imply Representational Similarity? An Identifiability Perspective
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2506.03784