This study examined how word identification is influenced by interword spacing and morphological complexity in Thai, a script without interword spacing. While previous research supported the facilitative effect of interword spacing on Thai word identification, they did not account for the potential effects of the words’ morphological structure. The challenge of word identification becomes more pronounced when readers have to identify compound words (e.g., bathroom) when reading sentences without interword spacing. In an eye-tracking experiment that manipulated interword spacing (unspaced, spaced) and noun type (bimorphemic compound, monomorphemic) in Thai sentences, we confirmed previous findings that interword spacing has a facilitative effect on word identification, as evidenced by shorter first fixation duration, gaze duration and total fixation time. Furthermore, we observed an interaction effect indicating that interword spacing had a larger facilitative effect on the identification of compounds compared to monomorphemic words. Our results also revealed that the morphological structure of Thai words can influence saccadic movements, e.g., the first fixation landing position was closer to the beginning of compounds than to simple words. We suggest that the orthography-language interface, a language-specific feature, should be considered a major component in eye movement models of reading.

Word processing during reading is known to be influenced by lexical features, especially word length, frequency, and predictability. This study examined the relative importance of these features in word processing during second language (L2) English reading. We used data from an eye-tracking corpus and applied a machine-learning approach to model word-level eye-tracking measures and identify key predictors. Predictors comprised several lexical features, including length, frequency, and predictability (e.g., surprisal). Additionally, sentence, passage, and reader characteristics were considered for comparison. The analysis found that word length was the most important variable across several eye-tracking measures. However, for certain measures, word frequency and predictability were more important than length, and in some cases, reader characteristics such as proficiency were more significant than lexical features. These findings highlight the complexity of word processing during reading, the shared processes between first language (L1) and L2 reading, and their potential to refine models of eye-movement control.

This paper provides a design solution to the existing problem of using eye trackers for large screens. Traditional eye trackers are limited to commercial and smaller-sized screens. However, as larger screens become increasingly popular and essential for various tasks, their impact needs further investigation in user performance and behavioral studies. This work introduces a design approach for adjustable guide rail system to make moving an eye tracker along with the user's head position possible. The testing results showcase robust, accurate and functions under varying real-world conditions, making it ideal for Human-Computer Interaction and User Experience Research. The Guide Rail design employed by this system is easy to manufacture and incorporates 3D printed parts making it easily reproducible and open for customization.

Highly frequent discourse particles (DPs) express speaker attitudes and guide utterance interpretation, but we still lack a satisfactory explanation of how DPs are actually processed. Some results show facilitation, while others show processing costs. Previous studies have aimed to elicit core meanings of DPs embedded in highly plausible contexts, in contrast to more unlikely contexts that force two quite different interpretations. The present study uses a novel eye-tracking experiment where DPs instead are presented in low-constraint contexts. The plausible interpretations consist of two ends of a natural scale: the state change of color that fades or becomes dirty (black to gray or white to gray). This design renders a more direct reflection of how DPs alter context interpretation. Results show that DPs induce immediate reanalysis, and this reanalysis differs in magnitude depending on the kind of DP used. We suggest that the processing of DPs involve three dimensions: i) linguistic intuition about the DP, ii) assumptions about speaker meaning and iii) contextual considerations. The results are interpreted through the communicative principle of language, under-specificity and the maxim of quantity. We also suggest that diverging results from previous studies in the field can be explained using the same analytical lens.

Whether or not pre-planning extends beyond the initial noun in a noun phrase depends, in part, on the phrase’s dependency structure. Dependency structure disambiguates, in many contexts, the noun phrase’s reference. In the present experiment (N = 64), we demonstrate that advance planning is affected by the extent to which a dependency supports semantic disambiguation. Participants produced noun phrases in response to picture arrays. Syntax and lexemes were held constant, but semantic scope was manipulated by varying the contrastive functions of the first and the second noun. Evidence from eye-movement data revealed a stronger tendency for early planning in the extended scope condition. This is evidence that pre-planning requirements of structurally complex noun phrases are, in at least some contexts, determined by semantic functions.

Most political science studies are, at root, about how people make decisions—how voters choose whether and for whom to vote, how prejudice influences political choices, and the effects of emotions and morals on political choice. However, what people are thinking during these decisions remains obscure; currently utilized methods leave us with a “black box” of decision making. Eye tracking offers a deeper insight into these processes by capturing respondents’ attention, salience, emotion, and understanding. But how applicable is this method to political science questions, and how does one go about using it? Here, we explain what eye tracking allows researchers to measure, how these measures are relevant to political science questions, and how political scientists without expertise in the method can nonetheless use it effectively. In particular, we clarify how researchers can understand the choices made in preset software in order to arrive at correct inferences from their data and discuss new developments in eye tracking methodology, including webcam eye tracking. We additionally provide templates for preregistering eye tracking studies in political science, as well as starter code for processing and analyzing eye tracking data.

Morphological knowledge refers to the ability to recognize and use morphemes correctly in syntactic contexts and word formation. This is crucial for learning a morphologically rich language like Finnish, which features both agglutinative and fusional morphology. In Finnish, agglutination occurs in forms like aamu: aamu+lla (‘morning: in the morning’), where a suffix is transparently added. Fusional features, as seen in ilta: illa+lla (‘evening: in the evening’), involve allomorphic stem changes that reduce transparency. We investigated the challenges posed by stem allomorphy for word recognition in isolation and in context for L2 learners and L1 speakers of Finnish. In a lexical decision task, L2 speakers had longer response times and higher error rates for semitransparent inflections, while L1 speakers showed longer response times for both transparent and semitransparent inflection types. In sentence reading, L2 speakers exhibited longer fixation times for semitransparent forms, whereas L1 speakers showed no significant effects. The results suggest that the challenges in L2 inflectional processing are more related to fusional than agglutinative features of the Finnish language.

Numerous developmental findings suggest that infants and toddlers engage predictive processing during language comprehension. However, a significant limitation of this research is that associative (bottom-up) and predictive (top-down) explanations are not readily differentiated. Following adult studies that varied predictiveness relative to semantic-relatedness to differentiate associative vs. predictive processes, the present study used eye-tracking to begin to disentangle the contributions of bottom-up and top-down mechanisms to infants’ real-time language processing. Replicating prior results, infants (14-19 months old) use successive semantically-related words across sentences (e.g., eat, yum, mouth) to predict upcoming nouns (e.g., cookie). However, we also provide evidence that using successive semantically-related words to predict is distinct from the bottom-up activation of the word itself. In a second experiment, we investigate the potential effects of repetition on the findings. This work is the first to reveal that infant language comprehension is affected by both associative and predictive processes.

When making decisions, people tend to look back and forth between the alternatives until they eventually make a choice. Eye-tracking research has established that these shifts in attention are strongly linked to choice outcomes. A predominant framework for understanding the dynamics of the choice process, and thus the effects of attention, is sequential sampling of information. However, existing methods for estimating the attention parameters in these models are computationally costly and overly flexible, and yield estimates with unknown precision and bias. Here we propose an estimation method that relies on a link between sequential sampling models and random utility models (RUM). This method uses familiar econometric tools (i.e., logistic regression) and yields estimates that appear to be unbiased and relatively precise compared to existing methods, in a small fraction of the computation time. The RUM thus appears to be a useful tool for estimating the effects of attention on choice.

We examine the ability of eye movement data to help understand the determinants of decision-making over risky prospects. We start with structural models of choice under risk, and use that structure to inform what we identify from the use of process data in addition to choice data. We find that information on eye movements does significantly affect the extent and nature of probability weighting behavior. Our structural model allows us to show the pathway of the effect, rather than simply identifying a reduced form effect. This insight should be of importance for the normative design of choice mechanisms for risky products. We also show that decision-response duration is no substitute for the richer information provided by eye-tracking.

The high rewards people desire are often unlikely. Here, we investigated whether decision-makers exploit such ecological correlations between risks and rewards to simplify their information processing. In a learning phase, participants were exposed to options in which risks and rewards were negatively correlated, positively correlated, or uncorrelated. In a subsequent risky choice task, where the emphasis was on making either a ‘fast’ or the ‘best’ possible choice, participants’ eye movements were tracked. The changes in the number, distribution, and direction of eye fixations in ‘fast’ trials did not differ between the risk–reward conditions. In ‘best’ trials, however, participants in the negatively correlated condition lowered their evidence threshold, responded faster, and deviated from expected value maximization more than in the other risk–reward conditions. The results underscore how conclusions about people’s cognitive processing in risky choice can depend on risk–reward structures, an often neglected environmental property.

Encountering new words multiple times in the input is crucial for incidental vocabulary acquisition. While there is extensive research exploring the impact of word frequency on both learning and processing of novel vocabulary during reading, there is a notable gap in studies examining how contextual factors impact these processes, especially when reading texts, rather than short sentences. The present study aims to fill this gap by exploring the effect of contextual diversity or sameness on adult L2 English learners’ processing and incidental learning of novel lexical items through repeated reading of complete texts. Participants (N = 42) read one short story three times as well as three different stories, while their eye movements were recorded. Each contextual condition (Same vs. Different) contained ten pseudowords, repeated six times across the treatment. Participants were tested on both immediate and delayed vocabulary learning via form and meaning recognition tests. Our results indicate that repeated readings of the same text led to faster processing as well as better short-term learning of novel vocabulary, although this advantage was not retained for long-term learning. In contrast, initial encoding and lexical integration took longer in the Different condition, although this was not reflected in higher vocabulary gains either in the short- or the long term.

Ideally, survey respondents read and understand survey instructions, questions, and response scales, and provide answers that carefully reflect their beliefs, attitudes, or knowledge. However, respondents may also arrive at their responses using cues or heuristics that facilitate the production of a response, but diminish the targeted information content. We use eye-tracking data as covariates in a Bayesian switching-mixture model to identify different response behaviors at the item–respondent level. The model distinguishes response behaviors that are predominantly influenced either positively or negatively by the previous response, and responses that reflect respondents’ preexisting knowledge and experiences of interest. We find that controlling for multiple types of adaptive response behaviors allows for a more informative analysis of survey data and respondents.

This study investigates Mandarin-speaking children’s (age 3–7) comprehension development of novel and conventional metonymy, combining online and offline methods. Both online and offline data show significantly better performances from the oldest group (6-to-7-year-old) and a delayed acquisition of conventional metonymy compared with novel metonymy. However, part of offline data shows no significant difference between adjacent age groups, while the eye-tracking data show a chronological development from age 3–7. Furthermore, in offline tasks, the three-year-old group features a high choice randomness and the four-to-five-year-olds show the longest reaction time. Therefore, we argue that, not only age but also metonymy type can influence metonymy acquisition, and that a lack of socio-cultural experience can be a source of acquisition difficulty for children under six. Methodologically speaking, we believe that online methods should not be considered superior to offline ones as they investigate different aspects of implicit and explicit language comprehension.

The Uniform Information Density (UID) hypothesis proposes that speakers communicate by transmitting information close to a constant rate. When choosing between two syntactic variants, it claims that speakers prefer the variant distributing information most evenly, avoiding signal peaks and troughs. If speakers prefer transmitting information uniformly, then comprehenders should also prefer a uniform signal, experiencing difficulty whenever confronted with informational peaks. However, the literature investigating this hypothesis has focused mostly on production, with only a few studies considering comprehension. In this study, we investigate comprehension in two eye-tracking experiments. Participants read sentences of two different lengths, reflecting different degrees of density, containing either a dense structure (a nominal compound, NC) or a structure that spreads the information through more words (a noun followed by a prepositional phrase, PP). Favoring the UID hypothesis, participants gazed longer at text segments following the critical structure when it was an NC than when it was a PP. They also regressed more in sentences containing longer structures. However, the pattern of results was not as clear as expected, potentially reflecting participants’ experience with the denser structure or task differences between production and comprehension. These aspects should be taken into account in future research investigating the UID hypothesis for comprehension.

Quantifier spreading (Q-spreading), children’s incorrect falsification of a universally-quantified sentence based on an ‘extra-object’ picture, may persist beyond childhood, and children adhere to Q-spreading without changing responses throughout testing. We examined the error patterns across wider age groups (aged 4-79) with a picture-sentence verification eye-tracking task. We also examined whether prosodic emphasis affects their comprehension and processing of universally-quantified sentences. Whereas adults’ comprehension was ceiling, children/adolescents (aged 4-17) showed various comprehension patterns, splitting into: ‘Adult-like responders’ (consistently adult-like), ‘Q-spreaders’ (consistently showing Q-spreading), and ‘Switchers’ (shifted from Q-spreading to adult-like). While adults rarely looked at the extra-object, ‘Q-spreaders’ showed frequent looks throughout testing, and both ‘Switchers’ and ‘Adult-like responders’ exhibited reduced looks to the extra-object, suggesting that avoidance and correction of Q-spreading requires inhibition of the visual attention to the extra-object. The effect of prosodic emphasis on eye movement emerged later for children/adolescents than adults.

We investigated the predictive processing of grammatical number information through stem-vowel alternations in German strong verbs by adult first language (L1) speakers and Dutch-speaking advanced second language (L2) learners of German, and the influence of working memory and awareness (i.e., whether participants consciously registered the predictive cue) thereon. While changed stem vowels indicate a singular referent (e.g., /ε/ in fällt3SG, “falls”), unchanged vowels indicate plural (e.g., /a/ in fallt2PL, “fall”). This target structure presents a challenge for L2 learners of German due to its subregularity and low salience. With their eye movements being tracked, participants matched German auditory sentences (VSO order) with one of two pictures, displaying identical action scenes but varying in agent number. The number cue provided by the strong verbs allowed participants to predict whether the upcoming subject would be singular or plural. The analyses revealed significant prediction, measured as predictive eye movements toward the target picture and faster button-press responses. Prediction in the L2 group was weaker than in the L1 group and present in the eye movement data only. Higher working memory scores were linked to faster predictive presses. Approximately half of the participants had become aware of the predictive cue, and being aware facilitated prediction to a limited extent.

Understanding user perceptions of interacting with the virtual world is one of the research focuses in recent years, given the rapid proliferation of virtual reality (VR) and driven to establish the metaverse. Users can generate a familiar connection between their bodies and the virtual world by being embodied in virtual hands, and hand representations can induce users’ embodiment in VR. The sense of embodiment represents the cognitive awareness of one's manifestation and includes three subcomponents: the sense of body ownership, agency and self-location. There is insufficient evidence in the literature about the effects of hand designs on the embodiment, especially based on studying its three subcomponents. This study investigates how virtual hand designs with five realism levels influence the three subcomponents of embodiment in VR. This research employs a self-report questionnaire commonly used in the literature to assess embodiment and evaluates agency and self-location by introducing implicit methods (intentional binding and proprioceptive measurement) derived from psychology. Besides, the objective data of eye tracking is used to explore the connection between embodiment and hand designs, and classifying participants’ eye tracking data to help analyze the link between embodiment and user attention. Overall, this research makes a major contribution through a systematic exploration of users’ embodied experience in VR and offers important evidence of the effects of virtual hand designs on body ownership, agency, and self-location, respectively. In addition, this study provides a valuable reference for further investigation of embodiment through implicit and objective methods, and practical design recommendations for virtual hand design in VR applications.