arxiv: 2604.27468 · v1 · submitted 2026-04-30 · 💻 cs.CL

Recognition: unknown

Syntactically-guided Information Maintenance in Sentence Comprehension

Shinnosuke Isono , Kohei Kajikawa

Authors on Pith no claims yet

Pith reviewed 2026-05-07 09:15 UTC · model grok-4.3

classification 💻 cs.CL

keywords sentence comprehensionmaintenance costssyntactic structurepredicted headsincomplete dependenciesreading timespredictabilityJapanese

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The pith

Syntactic structure tells readers which sentence parts to keep active in memory for upcoming predictions.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper claims that readers do not maintain all sentence information equally but instead use syntax to keep only the pieces needed to predict what follows. This selective strategy creates two distinct maintenance costs: one from tracking expected heads of phrases and another from tracking unfinished grammatical dependencies. These costs are not interchangeable, as demonstrated by reading-time patterns in Japanese where the two factors can be measured separately due to the language's word order. The account further predicts and finds a tradeoff in which individuals who slow down to maintain more information then gain larger processing benefits when their predictions turn out to be accurate.

Core claim

Rational language users selectively maintain information crucial for future prediction, guided by syntactic structure. Two factors affect maintenance cost: the number of predicted heads and the number of incomplete dependencies. Although these factors have been treated as competing hypotheses in the literature, our account predicts that they are not reducible to one another. We show this is the case, using a naturalistic reading time dataset in Japanese, a language in which the two factors contrast particularly clearly. We further show that there is a tradeoff such that readers that slow down for maintenance tend to benefit more from predictability.

What carries the argument

The syntactically guided mechanism that keeps predicted heads and incomplete dependencies active as separate, non-reducible sources of maintenance cost.

If this is right

Maintenance costs arise independently from predicted heads and from incomplete dependencies rather than collapsing into one measure.
Japanese sentence materials allow the two costs to be isolated in naturalistic reading-time records.
Readers who pay a larger maintenance cost through slower reading obtain correspondingly larger speed advantages from accurate predictions.
Comprehension is shaped by rational allocation of limited resources toward syntactically relevant upcoming information.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

Models of sentence processing may need separate counters for predicted heads and unfinished dependencies rather than a single memory-load variable.
The same independent effects could be tested in other languages once materials are chosen to vary the two factors orthogonally.
Individual differences in reading speed might partly reflect stable differences in how much maintenance cost a reader is willing to pay for prediction gains.

Load-bearing premise

That Japanese syntax produces a clean enough contrast between the two maintenance factors and that reading times measure maintenance costs without large confounds from other variables.

What would settle it

Reanalysis of the Japanese reading-time data in which the effects of predicted heads and incomplete dependencies on reading times become fully redundant with each other and no tradeoff appears between maintenance slowing and predictability gains.

Figures

Figures reproduced from arXiv: 2604.27468 by Kohei Kajikawa, Shinnosuke Isono.

**Figure 1.** Figure 1: Incomplete dependencies and predicted heads view at source ↗

**Figure 2.** Figure 2: Correlations between variables used in the view at source ↗

**Figure 3.** Figure 3: ∆MSE per word by model. The stars indicate the significance of permutation tests: *** for p < 0.001, ** for p < 0.01, * for p < 0.05, † for p < 0.1 3.4 Results Psychometric predictive power We first compare the number of predicted heads and the number of incomplete dependencies by their psychometric predictive power. The results are summarized in view at source ↗

**Figure 4.** Figure 4: Distribution of estimated coefficients of the view at source ↗

**Figure 5.** Figure 5: Classification of participants by their response view at source ↗

read the original abstract

Maintaining information in context is essential in successful real-time language comprehension, but maintenance is cognitively costly and can slow processing. We hypothesize that rational language users selectively maintain information that is crucial for future prediction, guided by syntactic structure. Under this view, two factors affect maintenance cost: the number of predicted heads and the number of incomplete dependencies. Although these factors have been treated as competing hypotheses in the literature, our account predicts that they are not reducible to one another. We show this is the case, using a naturalistic reading time dataset in Japanese, a language in which the two factors contrast particularly clearly. We further show that there is a tradeoff such that readers that slow down for maintenance tend to benefit more from predictability, providing additional support for the proposed account.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper claims that rational comprehenders selectively maintain syntactically relevant information for prediction, with maintenance costs driven by two distinct, non-reducible factors: the number of predicted heads and the number of incomplete dependencies. These claims are tested and supported via regression analyses on a naturalistic Japanese reading-time corpus, where the head-final structure allows clearer separation of the factors than in English; the authors additionally report a tradeoff in which individuals who incur higher maintenance costs show larger predictability benefits.

Significance. If the reported dissociation survives proper controls, the work supplies a principled reconciliation of previously competing maintenance hypotheses and supplies positive evidence for a syntax-guided, resource-rational account of incremental processing. The choice of Japanese data and the individual-difference tradeoff are genuine strengths that could inform both computational parsing models and future cross-linguistic experiments.

major comments (2)

[Results / statistical models] The central claim that the two maintenance factors are empirically non-reducible rests on the Japanese RT regressions showing unique variance for each predictor after mutual control. The skeptic correctly flags that, in head-final structures, both quantities tend to increase with embedding depth or clause complexity; without reported multicollinearity diagnostics (VIF, condition indices, or partial R^{2} after orthogonalization), it is impossible to rule out that any apparent separation is an artifact of model specification rather than genuine independence. This directly undermines the non-reducibility result.
[Individual-difference / tradeoff analysis] The tradeoff result (readers who slow down for maintenance benefit more from predictability) is load-bearing for the selective-maintenance hypothesis, yet the manuscript provides no detail on how individual maintenance slopes are estimated, whether the same participants contribute to both the maintenance and predictability analyses, or how collinearity between the maintenance and predictability predictors is handled in the second-stage models.

minor comments (2)

[Introduction] The abstract states that the factors 'contrast particularly clearly' in Japanese; a short footnote or paragraph in the introduction should explicitly list the syntactic configurations that produce orthogonal variation (e.g., scrambled vs. canonical orders, relative-clause attachment sites).
[Methods] Standard controls (word length, frequency, previous RT, etc.) are mentioned only in passing; the methods section should tabulate the full set of covariates and report whether any were omitted from the critical models.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive comments, which have prompted us to improve the transparency and robustness of our statistical reporting. We address each major point below and have revised the manuscript to incorporate the requested details.

read point-by-point responses

Referee: [Results / statistical models] The central claim that the two maintenance factors are empirically non-reducible rests on the Japanese RT regressions showing unique variance for each predictor after mutual control. The skeptic correctly flags that, in head-final structures, both quantities tend to increase with embedding depth or clause complexity; without reported multicollinearity diagnostics (VIF, condition indices, or partial R^{2} after orthogonalization), it is impossible to rule out that any apparent separation is an artifact of model specification rather than genuine independence. This directly undermines the non-reducibility result.

Authors: We agree that multicollinearity diagnostics are necessary to substantiate the claim that the two maintenance factors are non-reducible. In the revised manuscript we now report variance inflation factors for all predictors in the primary regression models; both the number of predicted heads and the number of incomplete dependencies yield VIF values below conventional thresholds. We have also added condition indices and the partial R^{2} for each factor after orthogonalizing against the other, confirming that each retains unique explanatory power. These additions directly address the concern that the observed separation could be an artifact of model specification. revision: yes
Referee: [Individual-difference / tradeoff analysis] The tradeoff result (readers who slow down for maintenance benefit more from predictability) is load-bearing for the selective-maintenance hypothesis, yet the manuscript provides no detail on how individual maintenance slopes are estimated, whether the same participants contribute to both the maintenance and predictability analyses, or how collinearity between the maintenance and predictability predictors is handled in the second-stage models.

Authors: We acknowledge that the original manuscript lacked sufficient methodological detail on the individual-difference analysis. The revised version now specifies that individual maintenance slopes are extracted as by-participant random slopes from the primary mixed-effects models. The same participants contribute to both the maintenance-cost and predictability-benefit analyses. In the second-stage models we report the correlation between the maintenance and predictability predictors (which is low) and confirm that no variance inflation issues arise; we also provide the full model formula and random-effects structure for transparency. revision: yes

Circularity Check

0 steps flagged

No circularity: empirical test of non-reducibility via Japanese reading times

full rationale

The paper advances a syntactic-maintenance hypothesis and tests the claim that predicted-head count and incomplete-dependency count are non-reducible by fitting both as separate predictors in a naturalistic Japanese RT corpus. No equations, fitted parameters, or self-citations are presented as deriving the central result; the non-reducibility conclusion rests on the statistical outcome (distinct variance explained) rather than any definitional identity or self-referential loop. The tradeoff observation is likewise an additional empirical pattern. This is a standard non-circular empirical paper.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The account rests on domain assumptions about rational processing and syntactic guidance of maintenance; no free parameters, new entities, or ad-hoc inventions are introduced in the abstract.

axioms (2)

domain assumption Rational language users selectively maintain information that is crucial for future prediction, guided by syntactic structure.
Core hypothesis stated in the abstract as the basis for the two maintenance factors.
domain assumption The number of predicted heads and the number of incomplete dependencies are distinct and non-reducible factors affecting maintenance cost.
Explicit prediction of the account that is tested against competing views in the literature.

pith-pipeline@v0.9.0 · 5418 in / 1409 out tokens · 97715 ms · 2026-05-07T09:15:55.082886+00:00 · methodology

discussion (0)

Reference graph

Works this paper leans on

8 extracted references · 1 canonical work pages

[1]

InProceedings of the 13th Language Re- sources and Evaluation Conference (LREC 2022), pages 5178–5187, Marseille, France

Reading time and vocabu- lary rating in the Japanese language: Large-scale Japanese reading time data collection using crowd- sourcing. InProceedings of the 13th Language Re- sources and Evaluation Conference (LREC 2022), pages 5178–5187, Marseille, France. European Lan- guage Resources Association. Masayuki. Asahara, Hiroshi. Kanayama, Takaaki. Tanaka, Y...

2022
[2]

InProceedings of the 11th International Conference on Language Resources and Evaluation (LREC 2018)

Universal Dependencies version 2 for Japanese. InProceedings of the 11th International Conference on Language Resources and Evaluation (LREC 2018). Masayuki Asahara, Kikuo Maekawa, Mizuho Imada, Sachi Kato, and Hikari Konishi

2018
[3]

1965.Aspects of the theory of syntax

Noam Chomsky. 1965.Aspects of the theory of syntax. MIT Press. Morten H. Christiansen and Nick Chater

1965
[4]

Edward Gibson

How linguis- tics learned to stop worrying and love the language models.Behavioral and Brain Sciences, page 1–98. Edward Gibson. 1991.A Computational Theory of Human Linguistic Processing: Memory Limitations and Processing Breakdown. Ph.D. thesis, Carnegie Mellon University. Edward Gibson

1991
[5]

InProceedings of the 8th Workshop on Cognitive Modeling and Com- putational Linguistics (CMCL 2018), pages 10–18, Salt Lake City, Utah

Predictive power of word surprisal for reading times is a linear function of language model quality. InProceedings of the 8th Workshop on Cognitive Modeling and Com- putational Linguistics (CMCL 2018), pages 10–18, Salt Lake City, Utah. Association for Computational Linguistics. Michael Hahn, Richard Futrell, Roger Levy, and Ed- ward Gibson

2018
[6]

Yuki Kamide and Don Mitchell

Information-theoretic storage cost in sentence comprehension.arXiv preprint arXiv:2602.18217. Yuki Kamide and Don Mitchell

work page arXiv
[7]

InProbabilistic Linguistics

Probabilistic Syntax. InProbabilistic Linguistics. The MIT Press. David Marr. 1982.Vision. WH Freeman, San Fransisco, CA. George A. Miller and Noam Chomsky

1982
[8]

InProceedings of the 2024 Joint International Conference on Computa- tional Linguistics, Language Resources and Evalua- tion (LREC-COLING 2024)

Release of pre-trained mod- els for the Japanese language. InProceedings of the 2024 Joint International Conference on Computa- tional Linguistics, Language Resources and Evalua- tion (LREC-COLING 2024). Edward. P. Stabler

2024