Seamless Deception: Larger Language Models Are Better Knowledge Concealers

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Ashok, Dhananjay, Armstrong, Ruth-Ann, May, Jonathan
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866914412060737536
author Ashok, Dhananjay
Armstrong, Ruth-Ann
May, Jonathan
author_facet Ashok, Dhananjay
Armstrong, Ruth-Ann
May, Jonathan
contents Language Models (LMs) may acquire harmful knowledge, and yet feign ignorance of these topics when under audit. Inspired by the recent discovery of deception-related behaviour patterns in LMs, we aim to train classifiers that detect when a LM is actively concealing knowledge. Initial findings on smaller models show that classifiers can detect concealment more reliably than human evaluators, with gradient-based concealment proving easier to identify than prompt-based methods. However, contrary to prior work, we find that the classifiers do not reliably generalize to unseen model architectures and topics of hidden knowledge. Most concerningly, the identifiable traces associated with concealment become fainter as the models increase in scale, with the classifiers achieving no better than random performance on any model exceeding 70 billion parameters. Our results expose a key limitation in black-box-only auditing of LMs and highlight the need to develop robust methods to detect models that are actively hiding the knowledge they contain.
format Preprint
id arxiv_https___arxiv_org_abs_2603_14672
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Seamless Deception: Larger Language Models Are Better Knowledge Concealers
Ashok, Dhananjay
Armstrong, Ruth-Ann
May, Jonathan
Computation and Language
Artificial Intelligence
Language Models (LMs) may acquire harmful knowledge, and yet feign ignorance of these topics when under audit. Inspired by the recent discovery of deception-related behaviour patterns in LMs, we aim to train classifiers that detect when a LM is actively concealing knowledge. Initial findings on smaller models show that classifiers can detect concealment more reliably than human evaluators, with gradient-based concealment proving easier to identify than prompt-based methods. However, contrary to prior work, we find that the classifiers do not reliably generalize to unseen model architectures and topics of hidden knowledge. Most concerningly, the identifiable traces associated with concealment become fainter as the models increase in scale, with the classifiers achieving no better than random performance on any model exceeding 70 billion parameters. Our results expose a key limitation in black-box-only auditing of LMs and highlight the need to develop robust methods to detect models that are actively hiding the knowledge they contain.
title Seamless Deception: Larger Language Models Are Better Knowledge Concealers
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2603.14672