Towards Universality: Studying Mechanistic Similarity Across Language Model Architectures

Fuente: arXiv
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Autori principali: Wang, Junxuan, Ge, Xuyang, Shu, Wentao, Tang, Qiong, Zhou, Yunhua, He, Zhengfu, Qiu, Xipeng
Natura: Preprint
Pubblicazione: 2024
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author Wang, Junxuan
Ge, Xuyang
Shu, Wentao
Tang, Qiong
Zhou, Yunhua
He, Zhengfu
Qiu, Xipeng
author_facet Wang, Junxuan
Ge, Xuyang
Shu, Wentao
Tang, Qiong
Zhou, Yunhua
He, Zhengfu
Qiu, Xipeng
contents The hypothesis of Universality in interpretability suggests that different neural networks may converge to implement similar algorithms on similar tasks. In this work, we investigate two mainstream architectures for language modeling, namely Transformers and Mambas, to explore the extent of their mechanistic similarity. We propose to use Sparse Autoencoders (SAEs) to isolate interpretable features from these models and show that most features are similar in these two models. We also validate the correlation between feature similarity and Universality. We then delve into the circuit-level analysis of Mamba models and find that the induction circuits in Mamba are structurally analogous to those in Transformers. We also identify a nuanced difference we call \emph{Off-by-One motif}: The information of one token is written into the SSM state in its next position. Whilst interaction between tokens in Transformers does not exhibit such trend.
format Preprint
id arxiv_https___arxiv_org_abs_2410_06672
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Towards Universality: Studying Mechanistic Similarity Across Language Model Architectures
Wang, Junxuan
Ge, Xuyang
Shu, Wentao
Tang, Qiong
Zhou, Yunhua
He, Zhengfu
Qiu, Xipeng
Computation and Language
The hypothesis of Universality in interpretability suggests that different neural networks may converge to implement similar algorithms on similar tasks. In this work, we investigate two mainstream architectures for language modeling, namely Transformers and Mambas, to explore the extent of their mechanistic similarity. We propose to use Sparse Autoencoders (SAEs) to isolate interpretable features from these models and show that most features are similar in these two models. We also validate the correlation between feature similarity and Universality. We then delve into the circuit-level analysis of Mamba models and find that the induction circuits in Mamba are structurally analogous to those in Transformers. We also identify a nuanced difference we call \emph{Off-by-One motif}: The information of one token is written into the SSM state in its next position. Whilst interaction between tokens in Transformers does not exhibit such trend.
title Towards Universality: Studying Mechanistic Similarity Across Language Model Architectures
topic Computation and Language
url https://arxiv.org/abs/2410.06672