Previous research has demonstrated that words associated with brightness (e.g., "sun") elicit smaller pupil diameters than those related to darkness (e.g., "night"). The present study aimed to determine whether these language-induced pupillary responses are driven by the luminance of the mentally simulated content-referred to here as sensory interpretation-or by the conceptual brightness linked to the words' emotional valence, termed emotional interpretation. To address this question, we utilized the Japanese adjectives akarui and kurai, which can denote both luminance, as in the noun phrase akarui/kurai gamen ("bright/dark screen"), and emotional valence, as in akarui/kurai seikaku ("cheerful/gloomy personality"). Participants were presented with noun phrases composed of these adjectives and various nouns (akarui/kurai + noun). A significant main effect of the adjective indicated that phrases containing akarui yielded smaller pupil diameters than those containing kurai. Furthermore, although the interaction effect did not reach significance, the adjective effect was observed only when the adjectives conveyed luminance, not when they conveyed emotional valence. These findings suggest that sensory, rather than emotional, interpretation better explains language-induced changes in pupil size. The use of pupillometry as a measure of perceptual simulation offers more direct and compelling evidence in support of the central claim of embodied language theories: that during language comprehension, readers and listeners spontaneously generate sensorimotor simulations of the described content. Future studies are warranted to examine whether these findings extend to sentence- and discourse-level processing, as well as to simulations of information conveyed implicitly or indirectly through language.

We investigated the mechanism of the lingering effect in relation to the garden-path effect based on self-paced reading and comprehension experiments in Japanese, which shows higher reanalysis success rates than English does. The lingering effect is a phenomenon whereby an initial misinterpretation persists in the final comprehension even after disambiguation. Through self-paced reading (Experiment 1) and comprehension tasks (Experiments 2 and 3), this study explored how the length and head position of ambiguous regions influence the garden-path and lingering effects. Our results indicate that the length and head position influenced the garden-path and lingering effects in different ways. In particular, a longer initial misparse strengthened the garden-path effect in a linear manner but weakened the lingering effect in a nonlinear manner. Additionally, surprisal affected the garden-path effect but not the lingering effect. These results support the notion that the garden-path and lingering effects are correlated but operate through different underlying processes. Specifically, the garden-path effect pertains to parsing, whereas the lingering effect relates to short-term memory.

Recent gesture studies investigating how speakers linearize events in which one entity acts on another have claimed that the preferred order is [subject/agent]-[object/patient]-[verb/action] (SOV/APV) irrespective of language background (Schouwstra et al., 2022; Goldin-Meadow et al., 2008). However, these studies have only tested speakers of languages in which the subject/agent preferentially precedes the object/patient. We provide a stronger test of this cognitive-universal hypothesis using elicited pantomime (plus a spoken-language comparison task) with speakers of Truku Seediq, which favors the typologically rare VOS/VPA word order, and English-speaking controls. While the English speakers' pantomimes largely employed the expected SOV/APV and SVO/AVP orders, the Truku Seediq speakers produced almost no APV sequences. The results strengthen the evidence for processing effects that promote SVO/AVP order under certain conditions, and further support the claim that the habitual use of a language may cumulatively influence speakers' cognitive activities as they are interpreting the world. The divergent preferences for the two typologically different languages suggest that language experience can change conceptual accessibility, especially in terms of action saliency, in speakers' cognition.

This study examines the neural mechanisms behind integrating syntactic and information structures during sentence comprehension using functional Magnetic Resonance Imaging. Focusing on Japanese sentences with canonical (SOV) and non-canonical (OSV) word orders, the study revealed distinct neural networks responsible for processing these linguistic structures. The left opercular part of the inferior frontal gyrus, left premotor area, and left posterior superior/middle temporal gyrus were primarily involved in syntactic processing. In contrast, the right inferior frontal sulcus, bilateral intraparietal sulci, and the left triangular part of the inferior frontal gyrus were linked to information structure processing. Importantly, the left opercular part of the inferior frontal gyrus (BA44) played a crucial role in integrating these structures during the later stages of comprehension, particularly when processing the second noun phrase. These findings enhance our understanding of the complex interplay between syntactic and information structures in language comprehension.

The present study examined why speakers of languages with flexible word orders are more likely to use syntactically complex non-basic word orders when they provide discourse-given information earlier in sentences. This may be because they are more efficient for speakers to produce (the Speaker Economy Hypothesis). Alternatively, speakers may produce them to help listeners understand sentences more efficiently (the Listener Economy Hypothesis), given that previous studies showed that the processing of non-basic word orders was facilitated when the felicitous context was provided (i.e. a displaced object refers to discourse-given information). We addressed this issue by conducting a picture-description experiment, in which participants uttered sentences with syntactically basic Subject-Object-Verb (SOV) or non-basic Object-Subject-Verb (OSV) in felicitous or infelicitous contexts while cognitive load was tracked using pupillometry and functional near-infrared spectroscopy. The results showed that the felicitous context facilitated the filler-gap dependency formation of OSVs in production, supporting the Speaker Economy Hypothesis.