Adaptive Activation Cancellation for Hallucination Mitigation in Large Language Models

Fuente: arXiv
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Autores principales: Yocam, Eric, Vaidyan, Varghese, Comert, Gurcan, Kalathas, Paris, Wang, Yong, Mwakalonge, Judith L.
Formato: Preprint
Publicado: 2026
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author Yocam, Eric
Vaidyan, Varghese
Comert, Gurcan
Kalathas, Paris
Wang, Yong
Mwakalonge, Judith L.
author_facet Yocam, Eric
Vaidyan, Varghese
Comert, Gurcan
Kalathas, Paris
Wang, Yong
Mwakalonge, Judith L.
contents Large Language Models frequently generate fluent but factually incorrect text. We propose Adaptive Activation Cancellation (AAC), a real-time inference-time framework that treats hallucination-associated neural activations as structured interference within the transformer residual stream, drawing an explicit analogy to classical adaptive noise cancellation from signal processing. The framework identifies Hallucination Nodes (H-Nodes) via layer-wise linear probing and suppresses them using a confidence-weighted forward hook during auto-regressive generation -- requiring no external knowledge, no fine-tuning, and no additional inference passes. Evaluated across OPT-125M, Phi-3-mini, and LLaMA 3-8B on TruthfulQA and HaluEval, the real-time hook is the only intervention that consistently improves downstream accuracy on all three scales. Critically, the method is strictly surgical: WikiText-103 perplexity and MMLU reasoning accuracy are preserved at exactly 0.0% degradation across all three model scales, a property that distinguishes AAC from interventions that trade fluency or general capability for factual improvement. On the LLaMA 3-8B scale, the hook additionally yields positive generation-level gains (MC1 +0.04; MC2 +0.003; Token-F1 +0.003) while achieving probe-space selectivity 5.94x - 3.5x higher than the ITI baseline -- demonstrating that targeted neuron-level suppression can simultaneously improve factual accuracy and preserve model capability.
format Preprint
id arxiv_https___arxiv_org_abs_2603_10195
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Adaptive Activation Cancellation for Hallucination Mitigation in Large Language Models
Yocam, Eric
Vaidyan, Varghese
Comert, Gurcan
Kalathas, Paris
Wang, Yong
Mwakalonge, Judith L.
Computation and Language
Artificial Intelligence
Machine Learning
I.2.7; I.2.6; I.5.1
Large Language Models frequently generate fluent but factually incorrect text. We propose Adaptive Activation Cancellation (AAC), a real-time inference-time framework that treats hallucination-associated neural activations as structured interference within the transformer residual stream, drawing an explicit analogy to classical adaptive noise cancellation from signal processing. The framework identifies Hallucination Nodes (H-Nodes) via layer-wise linear probing and suppresses them using a confidence-weighted forward hook during auto-regressive generation -- requiring no external knowledge, no fine-tuning, and no additional inference passes. Evaluated across OPT-125M, Phi-3-mini, and LLaMA 3-8B on TruthfulQA and HaluEval, the real-time hook is the only intervention that consistently improves downstream accuracy on all three scales. Critically, the method is strictly surgical: WikiText-103 perplexity and MMLU reasoning accuracy are preserved at exactly 0.0% degradation across all three model scales, a property that distinguishes AAC from interventions that trade fluency or general capability for factual improvement. On the LLaMA 3-8B scale, the hook additionally yields positive generation-level gains (MC1 +0.04; MC2 +0.003; Token-F1 +0.003) while achieving probe-space selectivity 5.94x - 3.5x higher than the ITI baseline -- demonstrating that targeted neuron-level suppression can simultaneously improve factual accuracy and preserve model capability.
title Adaptive Activation Cancellation for Hallucination Mitigation in Large Language Models
topic Computation and Language
Artificial Intelligence
Machine Learning
I.2.7; I.2.6; I.5.1
url https://arxiv.org/abs/2603.10195