Tokenized SAEs: Disentangling SAE Reconstructions

Fuente: arXiv
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Hauptverfasser: Dooms, Thomas, Wilhelm, Daniel
Format: Preprint
Veröffentlicht: 2025
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author Dooms, Thomas
Wilhelm, Daniel
author_facet Dooms, Thomas
Wilhelm, Daniel
contents Sparse auto-encoders (SAEs) have become a prevalent tool for interpreting language models' inner workings. However, it is unknown how tightly SAE features correspond to computationally important directions in the model. This work empirically shows that many RES-JB SAE features predominantly correspond to simple input statistics. We hypothesize this is caused by a large class imbalance in training data combined with a lack of complex error signals. To reduce this behavior, we propose a method that disentangles token reconstruction from feature reconstruction. This improvement is achieved by introducing a per-token bias, which provides an enhanced baseline for interesting reconstruction. As a result, significantly more interesting features and improved reconstruction in sparse regimes are learned.
format Preprint
id arxiv_https___arxiv_org_abs_2502_17332
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Tokenized SAEs: Disentangling SAE Reconstructions
Dooms, Thomas
Wilhelm, Daniel
Machine Learning
Sparse auto-encoders (SAEs) have become a prevalent tool for interpreting language models' inner workings. However, it is unknown how tightly SAE features correspond to computationally important directions in the model. This work empirically shows that many RES-JB SAE features predominantly correspond to simple input statistics. We hypothesize this is caused by a large class imbalance in training data combined with a lack of complex error signals. To reduce this behavior, we propose a method that disentangles token reconstruction from feature reconstruction. This improvement is achieved by introducing a per-token bias, which provides an enhanced baseline for interesting reconstruction. As a result, significantly more interesting features and improved reconstruction in sparse regimes are learned.
title Tokenized SAEs: Disentangling SAE Reconstructions
topic Machine Learning
url https://arxiv.org/abs/2502.17332