Why Prototypes Collapse: Diagnosing and Preventing Partial Collapse in Prototypical Self-Supervised Learning

Fuente: arXiv
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Autori principali: Arteaga, Gabriel Y., Aasan, Marius, Chakraborty, Rwiddhi, Hjelkrem-Tan, Martine, Silva, Thalles, Kampffmeyer, Michael, Rivera, Adín Ramírez
Natura: Preprint
Pubblicazione: 2025
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author Arteaga, Gabriel Y.
Aasan, Marius
Chakraborty, Rwiddhi
Hjelkrem-Tan, Martine
Silva, Thalles
Kampffmeyer, Michael
Rivera, Adín Ramírez
author_facet Arteaga, Gabriel Y.
Aasan, Marius
Chakraborty, Rwiddhi
Hjelkrem-Tan, Martine
Silva, Thalles
Kampffmeyer, Michael
Rivera, Adín Ramírez
contents Prototypical self-supervised learning methods consistently suffer from partial prototype collapse, where multiple prototypes converge to nearly identical representations. This undermines their central purpose -- providing diverse and informative targets to guide encoders toward rich representations -- and has led practitioners to over-parameterize prototype sets or add ad-hoc regularizers, which mitigate symptoms rather than address the root cause. We empirically trace the collapse to the joint optimization of encoders and prototypes, which encourages a type of shortcut learning: early in training prototypes drift toward redundant representations that minimize loss without necessarily enhancing representation diversity. To break the joint optimization, we introduce a fully decoupled training strategy that learns prototypes and encoders under separate objectives. Concretely, we model prototypes as a Gaussian mixture updated with an online EM-style procedure, independent of the encoder's loss. This simple yet principled decoupling eliminates prototype collapse without explicit regularization and yields consistently diverse prototypes and stronger downstream performance.
format Preprint
id arxiv_https___arxiv_org_abs_2510_20108
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Why Prototypes Collapse: Diagnosing and Preventing Partial Collapse in Prototypical Self-Supervised Learning
Arteaga, Gabriel Y.
Aasan, Marius
Chakraborty, Rwiddhi
Hjelkrem-Tan, Martine
Silva, Thalles
Kampffmeyer, Michael
Rivera, Adín Ramírez
Machine Learning
Computer Vision and Pattern Recognition
Prototypical self-supervised learning methods consistently suffer from partial prototype collapse, where multiple prototypes converge to nearly identical representations. This undermines their central purpose -- providing diverse and informative targets to guide encoders toward rich representations -- and has led practitioners to over-parameterize prototype sets or add ad-hoc regularizers, which mitigate symptoms rather than address the root cause. We empirically trace the collapse to the joint optimization of encoders and prototypes, which encourages a type of shortcut learning: early in training prototypes drift toward redundant representations that minimize loss without necessarily enhancing representation diversity. To break the joint optimization, we introduce a fully decoupled training strategy that learns prototypes and encoders under separate objectives. Concretely, we model prototypes as a Gaussian mixture updated with an online EM-style procedure, independent of the encoder's loss. This simple yet principled decoupling eliminates prototype collapse without explicit regularization and yields consistently diverse prototypes and stronger downstream performance.
title Why Prototypes Collapse: Diagnosing and Preventing Partial Collapse in Prototypical Self-Supervised Learning
topic Machine Learning
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2510.20108