Fine-Tuning is Subgraph Search: A New Lens on Learning Dynamics

Fuente: arXiv
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Autores principales: Li, Yueyan, Gao, Wenhao, Yuan, Caixia, Wang, Xiaojie
Formato: Preprint
Publicado: 2025
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author Li, Yueyan
Gao, Wenhao
Yuan, Caixia
Wang, Xiaojie
author_facet Li, Yueyan
Gao, Wenhao
Yuan, Caixia
Wang, Xiaojie
contents The study of mechanistic interpretability aims to reverse-engineer a model to explain its behaviors. While recent studies have focused on the static mechanism of a certain behavior, the learning dynamics inside a model remain to be explored. In this work, we develop a fine-tuning method for analyzing the mechanism behind learning. Inspired by the concept of intrinsic dimension, we view a model as a computational graph with redundancy for a specific task, and treat the fine-tuning process as a search for and optimization of a subgraph within this graph. Based on this hypothesis, we propose circuit-tuning, an algorithm that iteratively builds the subgraph for a specific task and updates the relevant parameters in a heuristic way. We first validate our hypothesis through a carefully designed experiment and provide a detailed analysis of the learning dynamics during fine-tuning. Subsequently, we conduct experiments on more complex tasks, demonstrating that circuit-tuning could strike a balance between the performance on the target task and the general capabilities. Our work offers a new analytical method for the dynamics of fine-tuning, provides new findings on the mechanisms behind the training process, and inspires the design of superior algorithms for the training of neural networks.
format Preprint
id arxiv_https___arxiv_org_abs_2502_06106
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fine-Tuning is Subgraph Search: A New Lens on Learning Dynamics
Li, Yueyan
Gao, Wenhao
Yuan, Caixia
Wang, Xiaojie
Machine Learning
Artificial Intelligence
Computation and Language
The study of mechanistic interpretability aims to reverse-engineer a model to explain its behaviors. While recent studies have focused on the static mechanism of a certain behavior, the learning dynamics inside a model remain to be explored. In this work, we develop a fine-tuning method for analyzing the mechanism behind learning. Inspired by the concept of intrinsic dimension, we view a model as a computational graph with redundancy for a specific task, and treat the fine-tuning process as a search for and optimization of a subgraph within this graph. Based on this hypothesis, we propose circuit-tuning, an algorithm that iteratively builds the subgraph for a specific task and updates the relevant parameters in a heuristic way. We first validate our hypothesis through a carefully designed experiment and provide a detailed analysis of the learning dynamics during fine-tuning. Subsequently, we conduct experiments on more complex tasks, demonstrating that circuit-tuning could strike a balance between the performance on the target task and the general capabilities. Our work offers a new analytical method for the dynamics of fine-tuning, provides new findings on the mechanisms behind the training process, and inspires the design of superior algorithms for the training of neural networks.
title Fine-Tuning is Subgraph Search: A New Lens on Learning Dynamics
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2502.06106