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Main Authors: Hao, Yixiong, Panda, Ayush, Shabalin, Stepan, Ali, Sheikh Abdur Raheem
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2505.03189
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author Hao, Yixiong
Panda, Ayush
Shabalin, Stepan
Ali, Sheikh Abdur Raheem
author_facet Hao, Yixiong
Panda, Ayush
Shabalin, Stepan
Ali, Sheikh Abdur Raheem
contents Controlling the behavior of Large Language Models (LLMs) remains a significant challenge due to their inherent complexity and opacity. While techniques like fine-tuning can modify model behavior, they typically require extensive computational resources. Recent work has introduced a class of contrastive activation engineering (CAE) techniques as promising approaches for steering LLM outputs through targeted modifications to their internal representations. Applied at inference-time with zero cost, CAE has the potential to introduce a new paradigm of flexible, task-specific LLM behavior tuning. We analyze the performance of CAE in in-distribution, out-of-distribution settings, evaluate drawbacks, and begin to develop comprehensive guidelines for its effective deployment. We find that 1. CAE is only reliably effective when applied to in-distribution contexts. 2. Increasing the number of samples used to generate steering vectors has diminishing returns at around 80 samples. 3. Steering vectors are susceptible to adversarial inputs that reverses the behavior that is steered for. 4. Steering vectors harm the overall model perplexity. 5. Larger models are more resistant to steering-induced degradation.
format Preprint
id arxiv_https___arxiv_org_abs_2505_03189
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Patterns and Mechanisms of Contrastive Activation Engineering
Hao, Yixiong
Panda, Ayush
Shabalin, Stepan
Ali, Sheikh Abdur Raheem
Artificial Intelligence
Human-Computer Interaction
Controlling the behavior of Large Language Models (LLMs) remains a significant challenge due to their inherent complexity and opacity. While techniques like fine-tuning can modify model behavior, they typically require extensive computational resources. Recent work has introduced a class of contrastive activation engineering (CAE) techniques as promising approaches for steering LLM outputs through targeted modifications to their internal representations. Applied at inference-time with zero cost, CAE has the potential to introduce a new paradigm of flexible, task-specific LLM behavior tuning. We analyze the performance of CAE in in-distribution, out-of-distribution settings, evaluate drawbacks, and begin to develop comprehensive guidelines for its effective deployment. We find that 1. CAE is only reliably effective when applied to in-distribution contexts. 2. Increasing the number of samples used to generate steering vectors has diminishing returns at around 80 samples. 3. Steering vectors are susceptible to adversarial inputs that reverses the behavior that is steered for. 4. Steering vectors harm the overall model perplexity. 5. Larger models are more resistant to steering-induced degradation.
title Patterns and Mechanisms of Contrastive Activation Engineering
topic Artificial Intelligence
Human-Computer Interaction
url https://arxiv.org/abs/2505.03189