Towards a Similarity-adjusted Surprisal Theory

Clara Meister, Mario Giulianelli, Tiago Pimentel


Abstract
Surprisal theory posits that the cognitive effort required to comprehend a word is determined by its contextual predictability, quantified assurprisal. Traditionally, surprisal theory treats words as distinct entities, overlooking any potential similarity between them. Giulianelli et al. (2023) address this limitation by introducing information value, a measure of predictability designed to account for similarities between communicative units. Our work leverages Ricotta and Szeidl’s (2006) diversity index to extend surprisal into a metric that we term similarity-adjusted surprisal, exposing a mathematical relationship between surprisal and information value. Similarity-adjusted surprisal aligns with information value when considering graded similarities and reduces to standard surprisal when words are treated as distinct. Experimental results with reading time data indicate that similarity-adjusted surprisal adds predictive power beyond standard surprisal for certain datasets, suggesting it serves as a complementary measure of comprehension effort.
Anthology ID:
2024.emnlp-main.921
Volume:
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Month:
November
Year:
2024
Address:
Miami, Florida, USA
Editors:
Yaser Al-Onaizan, Mohit Bansal, Yun-Nung Chen
Venue:
EMNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
16485–16498
Language:
URL:
https://aclanthology.org/2024.emnlp-main.921
DOI:
10.18653/v1/2024.emnlp-main.921
Bibkey:
Cite (ACL):
Clara Meister, Mario Giulianelli, and Tiago Pimentel. 2024. Towards a Similarity-adjusted Surprisal Theory. In Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing, pages 16485–16498, Miami, Florida, USA. Association for Computational Linguistics.
Cite (Informal):
Towards a Similarity-adjusted Surprisal Theory (Meister et al., EMNLP 2024)
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PDF:
https://aclanthology.org/2024.emnlp-main.921.pdf