Is Information Density Uniform when Utterances are Grounded on Perception and Discourse?

Matteo Gay, Coleman Haley, Mario Giulianelli, Edoardo Ponti


Abstract
The Uniform Information Density (UID) hypothesis posits that speakers are subject to a communicative pressure to distribute information evenly within utterances, minimising surprisal variance. While this hypothesis has been tested empirically, prior studies are limited exclusively to text-only inputs, abstracting away from the perceptual context in which utterances are produced. In this work, we present the first computational study of UID in visually grounded settings. We estimate surprisal using multilingual vision-and-language models over image–caption data in 30 languages and visual storytelling data in 13 languages, together spanning 11 families. We find that grounding on perception consistently smooths the distribution of information, increasing both global and local uniformity across typologically diverse languages compared to text-only settings. In visual narratives, grounding in both image and discourse contexts has additional effects, with the strongest surprisal reductions occurring at the onset of discourse units. Overall, this study takes a first step towards modelling the temporal dynamics of information flow in ecologically plausible, multimodal language use, and finds that grounded language exhibits greater information uniformity, supporting a context-sensitive formulation of UID.
Anthology ID:
2026.eacl-long.178
Volume:
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
EACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
3825–3853
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URL:
https://preview.aclanthology.org/ingest-eacl/2026.eacl-long.178/
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Bibkey:
Cite (ACL):
Matteo Gay, Coleman Haley, Mario Giulianelli, and Edoardo Ponti. 2026. Is Information Density Uniform when Utterances are Grounded on Perception and Discourse?. In Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers), pages 3825–3853, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
Is Information Density Uniform when Utterances are Grounded on Perception and Discourse? (Gay et al., EACL 2026)
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PDF:
https://preview.aclanthology.org/ingest-eacl/2026.eacl-long.178.pdf