Can LLMs Detect Their Confabulations? Estimating Reliability in Uncertainty-Aware Language Models

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Auteurs principaux: Zhou, Tianyi, Medina, Johanne, Chawla, Sanjay
Format: Preprint
Publié: 2025
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author Zhou, Tianyi
Medina, Johanne
Chawla, Sanjay
author_facet Zhou, Tianyi
Medina, Johanne
Chawla, Sanjay
contents Large Language Models (LLMs) are prone to generating fluent but incorrect content, known as confabulation, which poses increasing risks in multi-turn or agentic applications where outputs may be reused as context. In this work, we investigate how in-context information influences model behavior and whether LLMs can identify their unreliable responses. We propose a reliability estimation that leverages token-level uncertainty to guide the aggregation of internal model representations. Specifically, we compute aleatoric and epistemic uncertainty from output logits to identify salient tokens and aggregate their hidden states into compact representations for response-level reliability prediction. Through controlled experiments on open QA benchmarks, we find that correct in-context information improves both answer accuracy and model confidence, while misleading context often induces confidently incorrect responses, revealing a misalignment between uncertainty and correctness. Our probing-based method captures these shifts in model behavior and improves the detection of unreliable outputs across multiple open-source LLMs. These results underscore the limitations of direct uncertainty signals and highlight the potential of uncertainty-guided probing for reliability-aware generation.
format Preprint
id arxiv_https___arxiv_org_abs_2508_08139
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Can LLMs Detect Their Confabulations? Estimating Reliability in Uncertainty-Aware Language Models
Zhou, Tianyi
Medina, Johanne
Chawla, Sanjay
Computation and Language
Artificial Intelligence
Large Language Models (LLMs) are prone to generating fluent but incorrect content, known as confabulation, which poses increasing risks in multi-turn or agentic applications where outputs may be reused as context. In this work, we investigate how in-context information influences model behavior and whether LLMs can identify their unreliable responses. We propose a reliability estimation that leverages token-level uncertainty to guide the aggregation of internal model representations. Specifically, we compute aleatoric and epistemic uncertainty from output logits to identify salient tokens and aggregate their hidden states into compact representations for response-level reliability prediction. Through controlled experiments on open QA benchmarks, we find that correct in-context information improves both answer accuracy and model confidence, while misleading context often induces confidently incorrect responses, revealing a misalignment between uncertainty and correctness. Our probing-based method captures these shifts in model behavior and improves the detection of unreliable outputs across multiple open-source LLMs. These results underscore the limitations of direct uncertainty signals and highlight the potential of uncertainty-guided probing for reliability-aware generation.
title Can LLMs Detect Their Confabulations? Estimating Reliability in Uncertainty-Aware Language Models
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2508.08139