On the Role of Context in Reading Time Prediction

Andreas Opedal, Eleanor Chodroff, Ryan Cotterell, Ethan Wilcox


Abstract
We present a new perspective on how readers integrate context during real-time language comprehension. Our proposals build on surprisal theory, which posits that the processing effort of a linguistic unit (e.g., a word) is an affine function of its in-context information content. We first observe that surprisal is only one out of many potential ways that a contextual predictor can be derived from a language model. Another one is the pointwise mutual information (PMI) between a unit and its context, which turns out to yield the same predictive power as surprisal when controlling for unigram frequency. Moreover, both PMI and surprisal are correlated with frequency. This means that neither PMI nor surprisal contains information about context alone. In response to this, we propose a technique where we project surprisal onto the orthogonal complement of frequency, yielding a new contextual predictor that is uncorrelated with frequency. Our experiments show that the proportion of variance in reading times explained by context is a lot smaller when context is represented by the orthogonalized predictor. From an interpretability standpoint, this indicates that previous studies may have overstated the role that context has in predicting reading times.
Anthology ID:
2024.emnlp-main.179
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:
3042–3058
Language:
URL:
https://aclanthology.org/2024.emnlp-main.179
DOI:
Bibkey:
Cite (ACL):
Andreas Opedal, Eleanor Chodroff, Ryan Cotterell, and Ethan Wilcox. 2024. On the Role of Context in Reading Time Prediction. In Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing, pages 3042–3058, Miami, Florida, USA. Association for Computational Linguistics.
Cite (Informal):
On the Role of Context in Reading Time Prediction (Opedal et al., EMNLP 2024)
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https://aclanthology.org/2024.emnlp-main.179.pdf
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