From Directions to Cones: Exploring Multidimensional Representations of Propositional Facts in LLMs

Fuente: arXiv
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Main Authors: Yu, Stanley, Bulusu, Vaidehi, Yasunaga, Oscar, Lau, Clayton, Blondin, Cole, O'Brien, Sean, Zhu, Kevin, Sharma, Vasu
Format: Preprint
Published: 2025
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_version_ 1866908382030462976
author Yu, Stanley
Bulusu, Vaidehi
Yasunaga, Oscar
Lau, Clayton
Blondin, Cole
O'Brien, Sean
Zhu, Kevin
Sharma, Vasu
author_facet Yu, Stanley
Bulusu, Vaidehi
Yasunaga, Oscar
Lau, Clayton
Blondin, Cole
O'Brien, Sean
Zhu, Kevin
Sharma, Vasu
contents Large Language Models (LLMs) exhibit strong conversational abilities but often generate falsehoods. Prior work suggests that the truthfulness of simple propositions can be represented as a single linear direction in a model's internal activations, but this may not fully capture its underlying geometry. In this work, we extend the concept cone framework, recently introduced for modeling refusal, to the domain of truth. We identify multi-dimensional cones that causally mediate truth-related behavior across multiple LLM families. Our results are supported by three lines of evidence: (i) causal interventions reliably flip model responses to factual statements, (ii) learned cones generalize across model architectures, and (iii) cone-based interventions preserve unrelated model behavior. These findings reveal the richer, multidirectional structure governing simple true/false propositions in LLMs and highlight concept cones as a promising tool for probing abstract behaviors.
format Preprint
id arxiv_https___arxiv_org_abs_2505_21800
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle From Directions to Cones: Exploring Multidimensional Representations of Propositional Facts in LLMs
Yu, Stanley
Bulusu, Vaidehi
Yasunaga, Oscar
Lau, Clayton
Blondin, Cole
O'Brien, Sean
Zhu, Kevin
Sharma, Vasu
Machine Learning
Computation and Language
Large Language Models (LLMs) exhibit strong conversational abilities but often generate falsehoods. Prior work suggests that the truthfulness of simple propositions can be represented as a single linear direction in a model's internal activations, but this may not fully capture its underlying geometry. In this work, we extend the concept cone framework, recently introduced for modeling refusal, to the domain of truth. We identify multi-dimensional cones that causally mediate truth-related behavior across multiple LLM families. Our results are supported by three lines of evidence: (i) causal interventions reliably flip model responses to factual statements, (ii) learned cones generalize across model architectures, and (iii) cone-based interventions preserve unrelated model behavior. These findings reveal the richer, multidirectional structure governing simple true/false propositions in LLMs and highlight concept cones as a promising tool for probing abstract behaviors.
title From Directions to Cones: Exploring Multidimensional Representations of Propositional Facts in LLMs
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2505.21800