On the Role of Context in Reading Time Prediction

Fuente: arXiv
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Autores principales: Opedal, Andreas, Chodroff, Eleanor, Cotterell, Ryan, Wilcox, Ethan Gotlieb
Formato: Preprint
Publicado: 2024
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author Opedal, Andreas
Chodroff, Eleanor
Cotterell, Ryan
Wilcox, Ethan Gotlieb
author_facet Opedal, Andreas
Chodroff, Eleanor
Cotterell, Ryan
Wilcox, Ethan Gotlieb
contents 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.
format Preprint
id arxiv_https___arxiv_org_abs_2409_08160
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the Role of Context in Reading Time Prediction
Opedal, Andreas
Chodroff, Eleanor
Cotterell, Ryan
Wilcox, Ethan Gotlieb
Computation and Language
Machine Learning
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.
title On the Role of Context in Reading Time Prediction
topic Computation and Language
Machine Learning
url https://arxiv.org/abs/2409.08160