Analyzing LLMs' Knowledge Boundary Cognition Across Languages Through the Lens of Internal Representations

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Xiao, Chenghao, Chan, Hou Pong, Zhang, Hao, Aljunied, Mahani, Bing, Lidong, Moubayed, Noura Al, Rong, Yu
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866912445697622016
author Xiao, Chenghao
Chan, Hou Pong
Zhang, Hao
Aljunied, Mahani
Bing, Lidong
Moubayed, Noura Al
Rong, Yu
author_facet Xiao, Chenghao
Chan, Hou Pong
Zhang, Hao
Aljunied, Mahani
Bing, Lidong
Moubayed, Noura Al
Rong, Yu
contents While understanding the knowledge boundaries of LLMs is crucial to prevent hallucination, research on the knowledge boundaries of LLMs has predominantly focused on English. In this work, we present the first study to analyze how LLMs recognize knowledge boundaries across different languages by probing their internal representations when processing known and unknown questions in multiple languages. Our empirical studies reveal three key findings: 1) LLMs' perceptions of knowledge boundaries are encoded in the middle to middle-upper layers across different languages. 2) Language differences in knowledge boundary perception follow a linear structure, which motivates our proposal of a training-free alignment method that effectively transfers knowledge boundary perception ability across languages, thereby helping reduce hallucination risk in low-resource languages; 3) Fine-tuning on bilingual question pair translation further enhances LLMs' recognition of knowledge boundaries across languages. Given the absence of standard testbeds for cross-lingual knowledge boundary analysis, we construct a multilingual evaluation suite comprising three representative types of knowledge boundary data. Our code and datasets are publicly available at https://github.com/DAMO-NLP-SG/LLM-Multilingual-Knowledge-Boundaries.
format Preprint
id arxiv_https___arxiv_org_abs_2504_13816
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Analyzing LLMs' Knowledge Boundary Cognition Across Languages Through the Lens of Internal Representations
Xiao, Chenghao
Chan, Hou Pong
Zhang, Hao
Aljunied, Mahani
Bing, Lidong
Moubayed, Noura Al
Rong, Yu
Computation and Language
While understanding the knowledge boundaries of LLMs is crucial to prevent hallucination, research on the knowledge boundaries of LLMs has predominantly focused on English. In this work, we present the first study to analyze how LLMs recognize knowledge boundaries across different languages by probing their internal representations when processing known and unknown questions in multiple languages. Our empirical studies reveal three key findings: 1) LLMs' perceptions of knowledge boundaries are encoded in the middle to middle-upper layers across different languages. 2) Language differences in knowledge boundary perception follow a linear structure, which motivates our proposal of a training-free alignment method that effectively transfers knowledge boundary perception ability across languages, thereby helping reduce hallucination risk in low-resource languages; 3) Fine-tuning on bilingual question pair translation further enhances LLMs' recognition of knowledge boundaries across languages. Given the absence of standard testbeds for cross-lingual knowledge boundary analysis, we construct a multilingual evaluation suite comprising three representative types of knowledge boundary data. Our code and datasets are publicly available at https://github.com/DAMO-NLP-SG/LLM-Multilingual-Knowledge-Boundaries.
title Analyzing LLMs' Knowledge Boundary Cognition Across Languages Through the Lens of Internal Representations
topic Computation and Language
url https://arxiv.org/abs/2504.13816