The Queen of England is not England's Queen: On the Lack of Factual Coherency in PLMs

Fuente: arXiv
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Autores principales: Youssef, Paul, Schlötterer, Jörg, Seifert, Christin
Formato: Preprint
Publicado: 2024
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author Youssef, Paul
Schlötterer, Jörg
Seifert, Christin
author_facet Youssef, Paul
Schlötterer, Jörg
Seifert, Christin
contents Factual knowledge encoded in Pre-trained Language Models (PLMs) enriches their representations and justifies their use as knowledge bases. Previous work has focused on probing PLMs for factual knowledge by measuring how often they can correctly predict an object entity given a subject and a relation, and improving fact retrieval by optimizing the prompts used for querying PLMs. In this work, we consider a complementary aspect, namely the coherency of factual knowledge in PLMs, i.e., how often can PLMs predict the subject entity given its initial prediction of the object entity. This goes beyond evaluating how much PLMs know, and focuses on the internal state of knowledge inside them. Our results indicate that PLMs have low coherency using manually written, optimized and paraphrased prompts, but including an evidence paragraph leads to substantial improvement. This shows that PLMs fail to model inverse relations and need further enhancements to be able to handle retrieving facts from their parameters in a coherent manner, and to be considered as knowledge bases.
format Preprint
id arxiv_https___arxiv_org_abs_2402_01453
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Queen of England is not England's Queen: On the Lack of Factual Coherency in PLMs
Youssef, Paul
Schlötterer, Jörg
Seifert, Christin
Computation and Language
Factual knowledge encoded in Pre-trained Language Models (PLMs) enriches their representations and justifies their use as knowledge bases. Previous work has focused on probing PLMs for factual knowledge by measuring how often they can correctly predict an object entity given a subject and a relation, and improving fact retrieval by optimizing the prompts used for querying PLMs. In this work, we consider a complementary aspect, namely the coherency of factual knowledge in PLMs, i.e., how often can PLMs predict the subject entity given its initial prediction of the object entity. This goes beyond evaluating how much PLMs know, and focuses on the internal state of knowledge inside them. Our results indicate that PLMs have low coherency using manually written, optimized and paraphrased prompts, but including an evidence paragraph leads to substantial improvement. This shows that PLMs fail to model inverse relations and need further enhancements to be able to handle retrieving facts from their parameters in a coherent manner, and to be considered as knowledge bases.
title The Queen of England is not England's Queen: On the Lack of Factual Coherency in PLMs
topic Computation and Language
url https://arxiv.org/abs/2402.01453