Time-Aware Feature Selection: Adaptive Temporal Masking for Stable Sparse Autoencoder Training

Fuente: arXiv
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Autores principales: Li, T. Ed, Ren, Junyu
Formato: Preprint
Publicado: 2025
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author Li, T. Ed
Ren, Junyu
author_facet Li, T. Ed
Ren, Junyu
contents Understanding the internal representations of large language models is crucial for ensuring their reliability and safety, with sparse autoencoders (SAEs) emerging as a promising interpretability approach. However, current SAE training methods face feature absorption, where features (or neurons) are absorbed into each other to minimize $L_1$ penalty, making it difficult to consistently identify and analyze model behaviors. We introduce Adaptive Temporal Masking (ATM), a novel training approach that dynamically adjusts feature selection by tracking activation magnitudes, frequencies, and reconstruction contributions to compute importance scores that evolve over time. ATM applies a probabilistic masking mechanism based on statistical thresholding of these importance scores, creating a more natural feature selection process. Through extensive experiments on the Gemma-2-2b model, we demonstrate that ATM achieves substantially lower absorption scores compared to existing methods like TopK and JumpReLU SAEs, while maintaining excellent reconstruction quality. These results establish ATM as a principled solution for learning stable, interpretable features in neural networks, providing a foundation for more reliable model analysis.
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id arxiv_https___arxiv_org_abs_2510_08855
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Time-Aware Feature Selection: Adaptive Temporal Masking for Stable Sparse Autoencoder Training
Li, T. Ed
Ren, Junyu
Machine Learning
Artificial Intelligence
Computation and Language
Understanding the internal representations of large language models is crucial for ensuring their reliability and safety, with sparse autoencoders (SAEs) emerging as a promising interpretability approach. However, current SAE training methods face feature absorption, where features (or neurons) are absorbed into each other to minimize $L_1$ penalty, making it difficult to consistently identify and analyze model behaviors. We introduce Adaptive Temporal Masking (ATM), a novel training approach that dynamically adjusts feature selection by tracking activation magnitudes, frequencies, and reconstruction contributions to compute importance scores that evolve over time. ATM applies a probabilistic masking mechanism based on statistical thresholding of these importance scores, creating a more natural feature selection process. Through extensive experiments on the Gemma-2-2b model, we demonstrate that ATM achieves substantially lower absorption scores compared to existing methods like TopK and JumpReLU SAEs, while maintaining excellent reconstruction quality. These results establish ATM as a principled solution for learning stable, interpretable features in neural networks, providing a foundation for more reliable model analysis.
title Time-Aware Feature Selection: Adaptive Temporal Masking for Stable Sparse Autoencoder Training
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2510.08855