From Weights to Activations: Is Steering the Next Frontier of Adaptation?

Simon Ostermann, Daniil Gurgurov, Tanja Baeumel, Michael A. Hedderich, Sebastian Lapuschkin, Wojciech Samek, Vera Schmitt


Abstract
Post-training adaptation of large language models is commonly achieved through parameter updates or input based methods such as fine-tuning, parameter-efficient adaptation, and prompting. In parallel, a growing body of work modifies internal activations at inference time to influence model behavior, an approach known as steering. Despite increasing use, steering is rarely analyzed within the same conceptual framework as established adaptation methods.In this work, we argue that steering should be regarded as a form of model adaptation. We introduce a set of functional criteria for adaptation methods and use them to compare steering approaches with classical alternatives. This analysis positions steering as a distinct adaptation paradigm based on targeted interventions in activation space, enabling local and reversible behavioral change without parameter updates. The resulting framing clarifies how steering relates to existing methods, motivating a unified taxonomy for model adaptation.
Anthology ID:
2026.acl-long.1377
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
29854–29879
Language:
URL:
https://preview.aclanthology.org/paragraph-normalization/2026.acl-long.1377/
DOI:
10.18653/v1/2026.acl-long.1377
Bibkey:
Cite (ACL):
Simon Ostermann, Daniil Gurgurov, Tanja Baeumel, Michael A. Hedderich, Sebastian Lapuschkin, Wojciech Samek, and Vera Schmitt. 2026. From Weights to Activations: Is Steering the Next Frontier of Adaptation?. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 29854–29879, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
From Weights to Activations: Is Steering the Next Frontier of Adaptation? (Ostermann et al., ACL 2026)
Copy Citation:
PDF:
https://preview.aclanthology.org/paragraph-normalization/2026.acl-long.1377.pdf
Checklist:
 2026.acl-long.1377.checklist.pdf