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Main Authors: Xiao, Hanlin, Wang, Yang, Álvarez, Mauricio A., Breitling, Rainer
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2603.10619
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author Xiao, Hanlin
Wang, Yang
Álvarez, Mauricio A.
Breitling, Rainer
author_facet Xiao, Hanlin
Wang, Yang
Álvarez, Mauricio A.
Breitling, Rainer
contents The recent success of large pre-trained language models (PLMs) has motivated their integration into topic modeling. However, PLM-augmented topic models differ from classical co-occurrence models such as Latent Dirichlet Allocation (LDA) not only in performance, but also in the type of semantic structure they capture. We formalize this distinction along two psycholinguistic axes: thematic relatedness (dog/bone) and taxonomic similarity (dog/wolf). To measure both axes over topic words, we construct a large synthetic benchmark of word pairs using LLM-based annotation and train a neural scorer on it. Across multiple corpora and model families, the scorer places different topic-model families at distinct positions within the joint similarity-relatedness space. The two scores further predict downstream task performance: tasks requiring similarity benefit from similarity-rich topics, whereas tasks requiring relatedness benefit from the converse, and excessive emphasis on either axis degrades performance on tasks aligned with the opposing semantic structure. Neither axis is uniformly beneficial. Measuring both therefore provides a practical, model-agnostic diagnostic for evaluating the semantic structure captured by topic models.
format Preprint
id arxiv_https___arxiv_org_abs_2603_10619
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Disentangling Similarity and Relatedness in Topic Models
Xiao, Hanlin
Wang, Yang
Álvarez, Mauricio A.
Breitling, Rainer
Computation and Language
The recent success of large pre-trained language models (PLMs) has motivated their integration into topic modeling. However, PLM-augmented topic models differ from classical co-occurrence models such as Latent Dirichlet Allocation (LDA) not only in performance, but also in the type of semantic structure they capture. We formalize this distinction along two psycholinguistic axes: thematic relatedness (dog/bone) and taxonomic similarity (dog/wolf). To measure both axes over topic words, we construct a large synthetic benchmark of word pairs using LLM-based annotation and train a neural scorer on it. Across multiple corpora and model families, the scorer places different topic-model families at distinct positions within the joint similarity-relatedness space. The two scores further predict downstream task performance: tasks requiring similarity benefit from similarity-rich topics, whereas tasks requiring relatedness benefit from the converse, and excessive emphasis on either axis degrades performance on tasks aligned with the opposing semantic structure. Neither axis is uniformly beneficial. Measuring both therefore provides a practical, model-agnostic diagnostic for evaluating the semantic structure captured by topic models.
title Disentangling Similarity and Relatedness in Topic Models
topic Computation and Language
url https://arxiv.org/abs/2603.10619