Beyond Multiple Choice: Evaluating Steering Vectors for Summarization

Joschka Braun, Carsten Eickhoff, Seyed Ali Bahrainian


Abstract
Steering vectors are a lightweight method for controlling text properties by adding a learned bias to language model activations at inference time. While predominantly studied for multiple-choice and toy tasks, their effectiveness in free-form generation remains largely unexplored. Moving "Beyond Multiple Choice," we evaluate steering vectors for controlling topical focus, sentiment, toxicity, and readability in abstractive summaries across the SAMSum, NEWTS, and arXiv datasets. We find that steering effectively controls targeted properties, but high steering strengths consistently induce degenerate repetition and factual hallucinations. Prompting alone preserves summary quality but offers weaker control. Combining both methods yields the strongest control and the most favorable efficacy-quality trade-off at moderate steering strengths. Our work demonstrates that steering vectors face a critical control-quality trade-off in free-form generation, and that hybrid approaches offer best balance in practice.
Anthology ID:
2026.findings-eacl.200
Volume:
Findings of the Association for Computational Linguistics: EACL 2026
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
3849–3884
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URL:
https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.200/
DOI:
Bibkey:
Cite (ACL):
Joschka Braun, Carsten Eickhoff, and Seyed Ali Bahrainian. 2026. Beyond Multiple Choice: Evaluating Steering Vectors for Summarization. In Findings of the Association for Computational Linguistics: EACL 2026, pages 3849–3884, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
Beyond Multiple Choice: Evaluating Steering Vectors for Summarization (Braun et al., Findings 2026)
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https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.200.pdf
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