Mixture of Experts Made Intrinsically Interpretable

Fuente: arXiv
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Auteurs principaux: Yang, Xingyi, Venhoff, Constantin, Khakzar, Ashkan, de Witt, Christian Schroeder, Dokania, Puneet K., Bibi, Adel, Torr, Philip
Format: Preprint
Publié: 2025
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author Yang, Xingyi
Venhoff, Constantin
Khakzar, Ashkan
de Witt, Christian Schroeder
Dokania, Puneet K.
Bibi, Adel
Torr, Philip
author_facet Yang, Xingyi
Venhoff, Constantin
Khakzar, Ashkan
de Witt, Christian Schroeder
Dokania, Puneet K.
Bibi, Adel
Torr, Philip
contents Neurons in large language models often exhibit \emph{polysemanticity}, simultaneously encoding multiple unrelated concepts and obscuring interpretability. Instead of relying on post-hoc methods, we present \textbf{MoE-X}, a Mixture-of-Experts (MoE) language model designed to be \emph{intrinsically} interpretable. Our approach is motivated by the observation that, in language models, wider networks with sparse activations are more likely to capture interpretable factors. However, directly training such large sparse networks is computationally prohibitive. MoE architectures offer a scalable alternative by activating only a subset of experts for any given input, inherently aligning with interpretability objectives. In MoE-X, we establish this connection by rewriting the MoE layer as an equivalent sparse, large MLP. This approach enables efficient scaling of the hidden size while maintaining sparsity. To further enhance interpretability, we enforce sparse activation within each expert and redesign the routing mechanism to prioritize experts with the highest activation sparsity. These designs ensure that only the most salient features are routed and processed by the experts. We evaluate MoE-X on chess and natural language tasks, showing that it achieves performance comparable to dense models while significantly improving interpretability. MoE-X achieves a perplexity better than GPT-2, with interpretability surpassing even sparse autoencoder (SAE)-based approaches.
format Preprint
id arxiv_https___arxiv_org_abs_2503_07639
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Mixture of Experts Made Intrinsically Interpretable
Yang, Xingyi
Venhoff, Constantin
Khakzar, Ashkan
de Witt, Christian Schroeder
Dokania, Puneet K.
Bibi, Adel
Torr, Philip
Machine Learning
Computation and Language
Neurons in large language models often exhibit \emph{polysemanticity}, simultaneously encoding multiple unrelated concepts and obscuring interpretability. Instead of relying on post-hoc methods, we present \textbf{MoE-X}, a Mixture-of-Experts (MoE) language model designed to be \emph{intrinsically} interpretable. Our approach is motivated by the observation that, in language models, wider networks with sparse activations are more likely to capture interpretable factors. However, directly training such large sparse networks is computationally prohibitive. MoE architectures offer a scalable alternative by activating only a subset of experts for any given input, inherently aligning with interpretability objectives. In MoE-X, we establish this connection by rewriting the MoE layer as an equivalent sparse, large MLP. This approach enables efficient scaling of the hidden size while maintaining sparsity. To further enhance interpretability, we enforce sparse activation within each expert and redesign the routing mechanism to prioritize experts with the highest activation sparsity. These designs ensure that only the most salient features are routed and processed by the experts. We evaluate MoE-X on chess and natural language tasks, showing that it achieves performance comparable to dense models while significantly improving interpretability. MoE-X achieves a perplexity better than GPT-2, with interpretability surpassing even sparse autoencoder (SAE)-based approaches.
title Mixture of Experts Made Intrinsically Interpretable
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2503.07639