DisTaC: Conditioning Task Vectors via Distillation for Robust Model Merging

Fuente: arXiv
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Auteurs principaux: Yoshida, Kotaro, Naraki, Yuji, Horie, Takafumi, Shimizu, Ryotaro, Naganuma, Hiroki
Format: Preprint
Publié: 2025
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author Yoshida, Kotaro
Naraki, Yuji
Horie, Takafumi
Shimizu, Ryotaro
Naganuma, Hiroki
author_facet Yoshida, Kotaro
Naraki, Yuji
Horie, Takafumi
Shimizu, Ryotaro
Naganuma, Hiroki
contents Model merging has emerged as an efficient and flexible paradigm for multi-task learning, with numerous methods being proposed in recent years. However, these state-of-the-art techniques are typically evaluated on benchmark suites that are highly favorable to model merging, and their robustness in more realistic settings remains largely unexplored. In this work, we first investigate the vulnerabilities of model-merging methods and pinpoint the source-model characteristics that critically underlie them. Specifically, we identify two factors that are particularly harmful to the merging process: (1) disparities in task vector norms, and (2) the low confidence of the source models. To address this issue, we propose DisTaC (Distillation for Task vector Conditioning), a novel method that pre-conditions these problematic task vectors before the merge. DisTaC leverages knowledge distillation to adjust a task vector's norm and increase source-model confidence while preserving its essential task-specific knowledge. Our extensive experiments demonstrate that by pre-conditioning task vectors with DisTaC, state-of-the-art merging techniques can successfully integrate models exhibiting the harmful traits -- where they would otherwise fail -- achieving significant performance gains.
format Preprint
id arxiv_https___arxiv_org_abs_2508_01148
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle DisTaC: Conditioning Task Vectors via Distillation for Robust Model Merging
Yoshida, Kotaro
Naraki, Yuji
Horie, Takafumi
Shimizu, Ryotaro
Naganuma, Hiroki
Machine Learning
Model merging has emerged as an efficient and flexible paradigm for multi-task learning, with numerous methods being proposed in recent years. However, these state-of-the-art techniques are typically evaluated on benchmark suites that are highly favorable to model merging, and their robustness in more realistic settings remains largely unexplored. In this work, we first investigate the vulnerabilities of model-merging methods and pinpoint the source-model characteristics that critically underlie them. Specifically, we identify two factors that are particularly harmful to the merging process: (1) disparities in task vector norms, and (2) the low confidence of the source models. To address this issue, we propose DisTaC (Distillation for Task vector Conditioning), a novel method that pre-conditions these problematic task vectors before the merge. DisTaC leverages knowledge distillation to adjust a task vector's norm and increase source-model confidence while preserving its essential task-specific knowledge. Our extensive experiments demonstrate that by pre-conditioning task vectors with DisTaC, state-of-the-art merging techniques can successfully integrate models exhibiting the harmful traits -- where they would otherwise fail -- achieving significant performance gains.
title DisTaC: Conditioning Task Vectors via Distillation for Robust Model Merging
topic Machine Learning
url https://arxiv.org/abs/2508.01148