Information Representation Fairness in Long-Document Embeddings: The Peculiar Interaction of Positional and Language Bias

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Autori principali: Schuhmacher, Elias, Michail, Andrianos, Opitz, Juri, Sennrich, Rico, Clematide, Simon
Natura: Preprint
Pubblicazione: 2026
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author Schuhmacher, Elias
Michail, Andrianos
Opitz, Juri
Sennrich, Rico
Clematide, Simon
author_facet Schuhmacher, Elias
Michail, Andrianos
Opitz, Juri
Sennrich, Rico
Clematide, Simon
contents To be discoverable in an embedding-based search process, each part of a document should be reflected in its embedding representation. To quantify any potential reflection biases, we introduce a permutation-based evaluation framework. With this, we observe that state-of-the-art embedding models exhibit systematic positional and language biases when documents are longer and consist of multiple segments. Specifically, early segments and segments in higher-resource languages like English are over-represented, while later segments and segments in lower-resource languages are marginalized. In our further analysis, we find that the positional bias stems from front-loaded attention distributions in pooling-token embeddings, where early tokens receive more attention. To mitigate this issue, we introduce an inference-time attention calibration method that redistributes attention more evenly across document positions, increasing discoverabiltiy of later segments. Our evaluation framework and attention calibration is available at https://github.com/impresso/fair-sentence-transformers
format Preprint
id arxiv_https___arxiv_org_abs_2601_16934
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Information Representation Fairness in Long-Document Embeddings: The Peculiar Interaction of Positional and Language Bias
Schuhmacher, Elias
Michail, Andrianos
Opitz, Juri
Sennrich, Rico
Clematide, Simon
Computation and Language
Artificial Intelligence
To be discoverable in an embedding-based search process, each part of a document should be reflected in its embedding representation. To quantify any potential reflection biases, we introduce a permutation-based evaluation framework. With this, we observe that state-of-the-art embedding models exhibit systematic positional and language biases when documents are longer and consist of multiple segments. Specifically, early segments and segments in higher-resource languages like English are over-represented, while later segments and segments in lower-resource languages are marginalized. In our further analysis, we find that the positional bias stems from front-loaded attention distributions in pooling-token embeddings, where early tokens receive more attention. To mitigate this issue, we introduce an inference-time attention calibration method that redistributes attention more evenly across document positions, increasing discoverabiltiy of later segments. Our evaluation framework and attention calibration is available at https://github.com/impresso/fair-sentence-transformers
title Information Representation Fairness in Long-Document Embeddings: The Peculiar Interaction of Positional and Language Bias
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2601.16934