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Scene meaning is processed rapidly, with “gist” extracted even when presentation duration spans a few dozen milliseconds. This has led some to suggest a primacy of bottom-up information. However, gist research has typically relied on showing successions of unrelated scene images, contrary to our everyday experience in which the world unfolds around us in a predictable manner. Thus, we investigated whether top-down information—in the form of observers’ predictions of an upcoming scene—facilitates gist processing. Within each trial, participants (N = 370) experienced a series of images, organized to represent an approach to a destination (e.g., walking down a sidewalk), followed by a target scene either congruous or incongruous with the expected destination (e.g., a store interior or a bedroom). A series of behavioral experiments revealed that appropriate expectations facilitated gist processing; inappropriate expectations interfered with gist processing; sequentially-arranged scene images benefitted gist processing when semantically related to the target scene; expectation-based facilitation was most apparent when presentation duration was most curtailed; and findings were not simply the result of response bias. We then investigated the neural correlates of predictability on scene processing using event-related potentials (ERPs) (N = 24). Congruency-related differences were found in a putative scene-selective ERP component, related to integrating visual properties (P2), and in later components related to contextual integration including semantic and syntactic coherence (N400 and P600, respectively). Together, results suggest that in real-world situations, top-down predictions of an upcoming scene influence even the earliest stages of its processing, affecting both the integration of visual properties and meaning.

The presence of a weapon in a scene has been found to attract observers’ attention and to impair their memory of the person holding the weapon. Here, we examined the role of attention in this weapon focus effect (WFE) under different viewing conditions. German participants viewed stimuli in which a man committed a robbery while holding a gun or a cell phone. The stimuli were based on material used in a recent U.S. study reporting large memory effects. Recording eye movements allowed us to test whether observers’ attention in the gun condition shifted away from the perpetrator towards the gun, compared with the phone condition. When using videos (Experiment 1), weapon presence did not appear to modulate the viewing time for the perpetrator, whereas the evidence concerning the critical object remained inconclusive. When using slide shows (Experiment 2), the gun attracted more gaze than the phone, replicating previous research. However, the attentional shift towards the weapon did not come at a cost of viewing time on the perpetrator. In both experiments, observers focused their attention predominantly on the depicted people and much less on the gun or phone. The presence of a weapon did not cause participants to recall fewer details about the perpetrator’s appearance in either experiment. This null effect was replicated in an online study using the original videos and testing more participants. The results seem at odds with the attention-shift explanation of the WFE. Moreover, the results indicate that the WFE is not a universal phenomenon.

In this paper, we present a review of how the various aspects of any study using an eye tracker (such as the instrument, methodology, environment, participant, etc.) affect the quality of the recorded eye-tracking data and the obtained eye-movement and gaze measures. We take this review to represent the empirical foundation for reporting guidelines of any study involving an eye tracker. We compare this empirical foundation to five existing reporting guidelines and to a database of 207 published eye-tracking studies. We find that reporting guidelines vary substantially and do not match with actual reporting practices. We end by deriving a minimal, flexible reporting guideline based on empirical research (Section “An empirically based minimal reporting guideline”).

International audience; Human vision requires us to analyze the visual periphery to decide where to fixate next. In the present study, we investigated this process in people with age-related macular degeneration (AMD). In particular, we examined viewing biases and the extent to which visual salience guides fixation selection during free-viewing of naturalistic scenes. We used an approach combining generalized linear mixed modeling (GLMM) with a-priori scene parcellation. This method allows one to investigate group differences in terms of scene coverage and observers’ well-known tendency to look at the center of scene images. Moreover, it allows for testing whether image salience influences fixation probability above and beyond what can be accounted for by the central bias. Compared with age-matched normally sighted control subjects (and young subjects), AMD patients’ viewing behavior was less exploratory, with a stronger central fixation bias. All three subject groups showed a salience effect on fixation selection—higher-salience scene patches were more likely to be fixated. Importantly, the salience effect for the AMD group was of similar size as the salience effect for the control group, suggesting that guidance by visual salience was still intact. The variances for by-subject random effects in the GLMM indicated substantial individual differences. A separate model exclusively considered the AMD data and included fixation stability as a covariate, with the results suggesting that reduced fixation stability was associated with a reduced impact of visual salience on fixation selection.

Research on eye-movement control during natural scene viewing has investigated the degree to which the duration of individual fixations can be immediately adjusted to ongoing visual-cognitive processing demands. Results from several studies using the fixation-contingent scene quality paradigm suggest that the timing of fixations adapts to stimulus changes that occur on a fixation-to-fixation basis. Analysis of fixation-duration distributions has revealed that saccade-contingent degradations and enhancements of the scene stimulus have two qualitatively distinct types of influence. The surprise effect begins early in a fixation and is tied to surprising visual events such as unexpected stimulus changes. The encoding effect is tied to difficulties in visual-cognitive processing and occurs relatively late within a fixation. Here, we formalize an existing descriptive account of these two effects (referred to as the dual-process account) by using stochastic simulations. In the computational model, surprise and encoding related influences are implemented as time-dependent changes in the rate at which saccade timing and programming are completed during critical fixations. The model was tested on data from two experiments in which the luminance of the scene image was either decreased or increased during selected critical fixations (Walshe & Nuthmann, Vision Research, 100, 38–46, 2014). A counterfactual method was used to remove model components and to identify their specific influence on the fixation-duration distributions. The results suggest that the computational dual-process model provides a good account for the data from the luminance-change studies. We describe how the simulations can be generalized to explain a diverse set of experimental results.

We suggest a low-vision reading aid based on user-customized text presented on a head-mounted display (HMD), and make an initial comparison to optical aids in participants with age-related macular degeneration (AMD). Biomimetic scrolling, a novel method of text presentation which mimics the natural movements of the eye while reading, was previously invented: while the user maintains a steady gaze, text is scrolled horizontally across the display in a series of pauses and steps that resemble the natural fixations and saccades of reading. This method, along with rapid serial visual presentation, continuous scrolling, and static text, was presented on smart glasses to 23 participants with macular disease. Reading speed and subjective preference of the smart glasses was compared to reading text printed on paper using the participants’ habitual optical reading aid. Reading using smart glasses, the mean (±standard error) maximum reading speed was 122 ± 15 words per minute (wpm), compared to 74 ± 9 wpm using each participants’ habitual optical magnifier. This is a statistically significant difference as confirmed by a paired-sample t-test, t(17) = –4.61, p

We address two questions concerning eye guidance during visual search in naturalistic scenes. First, search has been described as a task in which visual salience is unimportant. Here, we revisit this question by using a letter-in-scene search task that minimizes any confounding effects that may arise from scene guidance. Second, we investigate how important the different regions of the visual field are for different subprocesses of search (target localization, verification). In Experiment 1, we manipulated both the salience (low vs. high) and the size (small vs. large) of the target letter (a “T”), and we implemented a foveal scotoma (radius: 1°) in half of the trials. In Experiment 2, observers searched for high- and low-salience targets either with full vision or with a central or peripheral scotoma (radius: 2.5°). In both experiments, we found main effects of salience with better performance for high-salience targets. In Experiment 1, search was faster for large than for small targets, and high-salience helped more for small targets. When searching with a foveal scotoma, performance was relatively unimpaired regardless of the target's salience and size. In Experiment 2, both visual-field manipulations led to search time costs, but the peripheral scotoma was much more detrimental than the central scotoma. Peripheral vision proved to be important for target localization, and central vision for target verification. Salience affected eye movement guidance to the target in both central and peripheral vision. Collectively, the results lend support for search models that incorporate salience for predicting eye-movement behavior.

The importance of high-acuity foveal vision to visual search can be assessed by denying foveal vision using the gaze-contingent Moving Mask technique. Foveal vision was necessary to attain normal performance when searching for a target letter in alphanumeric displays, Perception & Psychophysics, 62 (2000) 576–585. In contrast, foveal vision was not necessary to correctly locate and identify medium-sized target objects in natural scenes, Journal of Experimental Psychology: Human Perception and Performance, 40 (2014) 342–360. To explore these task differences, we used grayscale pictures of real-world scenes which included a target letter (Experiment 1: T, Experiment 2: T or L). To reduce between-scene variability with regard to target salience, we developed the Target Embedding Algorithm (T.E.A.) to place the letter in a location for which there was a median change in local contrast when inserting the letter into the scene. The presence or absence of foveal vision was crossed with four target sizes. In both experiments, search performance decreased for smaller targets, and was impaired when searching the scene without foveal vision. For correct trials, the process of target localization remained completely unimpaired by the foveal scotoma, but it took longer to accept the target. We reasoned that the size of the target may affect the importance of foveal vision to the task, but the present data remain ambiguous. In summary, the data highlight the importance of extrafoveal vision for target localization, and the importance of foveal vision for target verification during letter-in-scene search.

How important foveal, parafoveal, and peripheral vision are depends on the task. For object search and letter search in static images of real-world scenes, peripheral vision is crucial for efficient search guidance, whereas foveal vision is relatively unimportant. Extending this research, we used gaze-contingent Blindspots and Spotlights to investigate visual search in complex dynamic and static naturalistic scenes. In Experiment 1, we used dynamic scenes only, whereas in Experiments 2 and 3, we directly compared dynamic and static scenes. Each scene contained a static, contextually irrelevant target (i.e., a gray annulus). Scene motion was not predictive of target location. For dynamic scenes, the search-time results from all three experiments converge on the novel finding that neither foveal nor central vision was necessary to attain normal search proficiency. Since motion is known to attract attention and gaze, we explored whether guidance to the target was equally efficient in dynamic as compared to static scenes. We found that the very first saccade was guided by motion in the scene. This was not the case for subsequent saccades made during the scanning epoch, representing the actual search process. Thus, effects of task-irrelevant motion were fast-acting and short-lived. Furthermore, when motion was potentially present (Spotlights) or absent (Blindspots) in foveal or central vision only, we observed differences in verification times for dynamic and static scenes (Experiment 2). When using scenes with greater visual complexity and more motion (Experiment 3), however, the differences between dynamic and static scenes were much reduced.

There is ongoing debate on whether object meaning can be processed outside foveal vision, making semantics available for attentional guidance. Much of the debate has centred on whether objects that do not fit within an overall scene draw attention, in complex displays that are often difficult to control. Here, we revisited the question by reanalysing data from three experiments that used displays consisting of standalone objects from a carefully controlled stimulus set. Observers searched for a target object, as per auditory instruction. On the critical trials, the displays contained no target but objects that were semantically related to the target, visually related, or unrelated. Analyses using (generalized) linear mixed-effects models showed that, although visually related objects attracted most attention, semantically related objects were also fixated earlier in time than unrelated objects. Moreover, semantic matches affected the very first saccade in the display. The amplitudes of saccades that first entered semantically related objects were larger than 5° on average, confirming that object semantics is available outside foveal vision. Finally, there was no semantic capture of attention for the same objects when observers did not actively look for the target, confirming that it was not stimulus-driven. We discuss the implications for existing models of visual cognition.

Which image characteristics predict where people fixate when memorizing natural images? To answer this question, we introduce a new analysis approach that combines a novel scene-patch analysis with generalized linear mixed models (GLMMs). Our method allows for (1) directly describing the relationship between continuous feature value and fixation probability, and (2) assessing each feature's unique contribution to fixation selection. To demonstrate this method, we estimated the relative contribution of various image features to fixation selection: luminance and luminance contrast (low-level features); edge density (a mid-level feature); visual clutter and image segmentation to approximate local object density in the scene (higher-level features). An additional predictor captured the central bias of fixation. The GLMM results revealed that edge density, clutter, and the number of homogenous segments in a patch can independently predict whether image patches are fixated or not. Importantly, neither luminance nor contrast had an independent effect above and beyond what could be accounted for by the other predictors. Since the parcellation of the scene and the selection of features can be tailored to the specific research question, our approach allows for assessing the interplay of various factors relevant for fixation selection in scenes in a powerful and flexible manner.

Readers utilize parafoveal information about upcoming words and read less well when this information is denied. McConkie and Rayner (1975) enabled this issue to be explored by developing the moving window paradigm in which the experimenter varies the amount or the quality of the parafoveal information available around the current fixation point. We present a novel binocular version of the moving window technique to study the roles of the two eyes in reading, and we describe a basic experiment allowed by this technique. In the binocular moving window paradigm, each eye contributes its own window to a composite binocular window onto the text. We studied the reading of single lines of text in three conditions: no windows, a symmetrical 8-letters-left and 8-letters-right window for each eye, and a leftward-skewed 14-letters-left and 2-letters-right window for each eye. Note that both eyes saw the composite window onto the text. We tested the hypothesis that readers could be encouraged to generate a greater bi...

Previous research on eye guidance in reading has investigated systematic tendencies with respect to horizontal fixation locations on letters within words and the relationship between fixation location in a word and the duration of the fixation. The present study investigates where readers place their eyes vertically on the line of text and how vertical fixation location is related to fixation duration. Analyses were based on a large corpus of eye movement recordings from single-sentence reading. The vertical preferred viewing location was found to be within the vertical extent of the font, but fixations beyond the vertical boundaries of the text also frequently occurred. Analyzing fixation duration as a function of vertical fixation location revealed a vertical optimal viewing position (vOVP) effect: Fixations were shortest when placed optimally on the line of text, and fixation duration gradually increased for fixations that fell above or below the line of text. The vOVP effect can be explained by the limits of visual resolution along the vertical meridian. It is concluded that vertical and horizontal landing positions in single-sentence reading are associated with differences in fixation durations in opposite ways.

The current study investigated from how large a region around their current point of gaze viewers can take in information when searching for objects in real-world scenes. Visual span size was estimated using the gaze-contingent moving window paradigm. Experiment 1 featured window radii measuring 1, 3, 4, 4.7, 5.4, and 6.1°. Experiment 2 featured six window radii measuring between 5 and 10°. Each scene occupied a 24.8 × 18.6° field of view. Inside the moving window, the scene was presented in high resolution. Outside the window, the scene image was low-pass filtered to impede the parsing of the scene into constituent objects. Visual span was defined as the window size at which object search times became indistinguishable from search times in the no-window control condition; this occurred with windows measuring 8° and larger. Notably, as long as central vision was fully available (window radii ≥ 5°), the distance traversed by the eyes through the scene to the search target was comparable to baseline perform...

Recent research on eye movements during scene viewing has primarily focused on where the eyes fixate. But eye fixations also differ in their durations. Here we investigated whether fixation durations in scene viewing are under the direct and immediate control of the current visual input. Subjects freely viewed photographs of scenes in preparation for a later memory test while their eye movements were recorded. Using a novel scene degradation paradigm based on a saccade-contingent display change method, scenes were reduced in luminance during saccades ending in critical fixations. Results from two experiments showed that the durations of the critical fixations were immediately affected by scene luminance, with a monotonic relationship between luminance reduction and fixation duration. The results are the first to demonstrate that fixation durations in scene viewing are immediately influenced by the ease of processing of the image currently in view. These results are consistent with the CRISP (a timer-Controlled Random-Walk with Inhibition for Saccade Planning) computational model of saccade generation in scenes, proposing that difficulty in moment-by-moment visual and cognitive processing of the scene modulates fixation durations.

Saccades to single targets in peripheral vision are typically characterized by an undershoot bias. Putting this bias to a test, Kapoula [1] used a paradigm in which observers were presented with two different sets of target eccentricities that partially overlapped each other. Her data were suggestive of a saccadic range effect (SRE): There was a tendency for saccades to overshoot close targets and undershoot far targets in a block, suggesting that there was a response bias towards the center of eccentricities in a given block. Our Experiment 1 was a close replication of the original study by Kapoula [1]. In addition, we tested whether the SRE is sensitive to top-down requirements associated with the task, and we also varied the target presentation duration. In Experiments 1 and 2, we expected to replicate the SRE for a visual discrimination task. The simple visual saccade-targeting task in Experiment 3, entailing minimal top-down influence, was expected to elicit a weaker SRE. Voluntary saccades to remembered target locations in Experiment 3 were expected to elicit the strongest SRE. Contrary to these predictions, we did not observe a SRE in any of the tasks. Our findings complement the results reported by Gillen et al. [2] who failed to find the effect in a saccade-targeting task with a very brief target presentation. Together, these results suggest that unlike arm movements, saccadic eye movements are not biased towards making saccades of a constant, optimal amplitude for the task., Postprints der Universität Potsdam : Humanwissenschaftliche Reihe, 506

We present a novel method of text presentation, saccadic scrolling, that translates average eye movement behavior into the movement of a line of text. It seeks to emulate the success of techniques such as rapid serial visual presentation in boosting reading speed, whilst maintaining the familiar line of text appearance. The parameters of saccadic scrolling are described and then tested in a reading speed study with 30 participants. Reading with saccadic scrolling was found to enable all participants to read faster than with continuous scrolling, on average by a factor of 5 times, and almost half to read faster than with rapid serial visual presentation, with a statistically equal average.

The goal of this article is to investigate the unexplored mechanisms underlying the development of saccadic control in infancy by determining the generalizability and potential limitations of extending the CRISP theoretical framework and computational model of fixation durations (FDs) in adult scene-viewing to infants. The CRISP model was used to investigate the underlying mechanisms modulating FDs in 6-month-olds by applying the model to empirical eye-movement data gathered from groups of infants and adults during free-viewing of naturalistic and semi-naturalistic videos. Participants also performed a gap-overlap task to measure their disengagement abilities. Results confirmed the CRISP model’s applicability to infant data. Specifically, model simulations support the view that infant saccade programming is completed in two stages: an initial labile stage, followed by a non-labile stage. Moreover, results from the empirical data and simulation studies highlighted the influence of the material viewed on the FD distributions in infants and adults, as well as the impact that the developmental state of the oculomotor system can have on saccade programming and execution at 6 months. The present work suggests that infant FDs reflect on-line perceptual and cognitive activity in a similar way to adults, but that the individual developmental state of the oculomotor system affects this relationship at 6 months. Furthermore, computational modeling filled the gaps of psychophysical studies and allowed the effects of these two factors on FDs to be simulated in infant data providing greater insights into the development of oculomotor and attentional control than can be gained from behavioral results alone.

The visual system utilizes environmental features to direct gaze efficiently when locating objects. While previous research has isolated various features’ contributions to gaze guidance, these studies generally used sparse displays and did not investigate how features facilitated search as a function of their location on the visual field. The current study investigated how features across the visual field – particularly color – facilitate gaze guidance during real-world search. A gaze-contingent window followed participants’ eye movements, restricting color information to specified regions. Scene images were presented in full color, with color in the periphery and gray in central vision, gray in the periphery and color in central vision, or in grayscale. Color conditions were crossed with a search cue manipulation, with the target cued either with a word label or an exact picture. Search times increased as color information in the scene decreased. A gaze-data based decomposition of search time revealed color-mediated effects on specific sub-processes of search. Color in peripheral vision facilitated target localization, whereas color in central vision facilitated target verification. Picture cues facilitated search, with the effects of cue specificity and scene color combining additively. When available, the visual system utilizes the environment’s color information to facilitate different real-world visual search behaviors based on the location within the visual field.

When the mind wanders, attention turns away from the external environment and cognitive processing is decoupled from perceptual information. Mind wandering is usually treated as a dichotomy (dichotomy-hypothesis), and is often measured using self-reports. Here, we propose the levels of inattention hypothesis, which postulates attentional decoupling to graded degrees at different hierarchical levels of cognitive processing. To measure graded levels of attentional decoupling during reading we introduce the sustained attention to stimulus task (SAST), which is based on psychophysics of error detection. Under experimental conditions likely to induce mind wandering, we found that subjects were less likely to notice errors that required high-level processing for their detection as opposed to errors that only required low-level processing. Eye tracking revealed that before errors were overlooked influences of high- and low-level linguistic variables on eye fixations were reduced in a graded fashion, indicating episodes of mindless reading at weak and deep levels. Individual fixation durations predicted overlooking of lexical errors 5s before they occurred. Our findings support the levels of inattention hypothesis and suggest that different levels of mindless reading can be measured behaviorally in the SAST. Using eye tracking to detect mind wandering online represents a promising approach for the development of new techniques to study mind wandering and to ameliorate its negative consequences.

Fixation durations vary when we read text or inspect a natural scene. Past studies suggest that this variability is controlled by the visual input available within the current fixation. The present study directly compared the control of fixation durations in reading and scene viewing in a common experimental paradigm, and attempted to account for the control of these durations within a common modelling framework using the CRISP architecture (Nuthmann, Smith, Engbert, & Henderson, 2010). In the experimental paradigm, a stimulus onset delay paradigm was used. A visual mask was presented at the beginning of critical fixations, which delayed the onset of the text or scene, and the length of the delay was varied. Irrespective of task, two populations of fixation durations were observed. One population of fixations was under the direct control of the current stimulus, increasing in duration as delay increased. A second population of fixation durations was relatively constant across delay. Additional task-specific quantitative differences in the adjustment of fixation durations were found. The pattern of mixed control of fixation durations obtained for scene viewing has been previously simulated with the CRISP model of fixation durations. In the present work, the model's generality was tested by applying its architecture to the text reading data, with task-specific influences realized by different parameter settings. The results of the numerical simulations suggest that global characteristics of fixation durations in scene viewing and reading can be explained by a common mechanism.

As Chinese is written without orthographical word boundaries (i.e., spaces), it is unclear whether saccade targets are selected on the basis of characters or words and whether saccades are aimed at the beginning or the centre of words. Here, we report an experiment where 30 Chinese readers read 150 sentences while their eye movements were monitored. They exhibited a strong tendency to fixate at the word centre in single-fixation cases and at the word beginning in multiple-fixation cases. Different from spaced alphabetic script, initial fixations falling at the end of words were no more likely to be followed by a refixation than initial fixations at word centre. Further, single fixations were shorter than first fixations in two-fixation cases, which is opposite to what is found in Roman script. We propose that Chinese readers dynamically select the beginning or centre of words as saccade targets depending on failure or success with segmentation of parafoveal word boundaries.

In this article, we revisit the mindless reading paradigm from the perspective of computational modeling. In the standard version of the paradigm, participants read sentences in both their normal version as well as the transformed (or mindless) version where each letter is replaced with a z. z-String scanning shares the oculomotor requirements with reading but none of the higher-level lexical and semantic processes. Here we use the z-string scanning task to validate the SWIFT model of saccade generation [Engbert, R., Nuthmann, A., Richter, E., \& Kliegl, R. (2005). SWIFT: A dynamical model of saccade generation during reading. Psychological Review, 112(4), 777-813] as an example for an advanced theory of eye-movement control in reading. We test the central assumption of spatially distributed processing across an attentional gradient proposed by the SWIFT model. Key experimental results like prolonged average fixation durations in z-string scanning compared to normal reading and the existence of a string-length effect on fixation durations and probabilities were reproduced by the model, which lends support to the model's assumptions on visual processing. Moreover, simulation results for patterns of regressive saccades in z-string scanning confirm SWIFT's concept of activation field dynamics for the selection of saccade targets. (c) 2008 Elsevier Ltd. All rights reserved.

Whether overt attention in natural scenes is guided by object content or by low-level stimulus features has become a matter of intense debate. Experimental evidence seemed to indicate that once object locations in a scene are known, salience models provide little extra explanatory power. This approach has recently been criticized for using inadequate models of early salience; and indeed, state-of-the-art salience models outperform trivial object-based models that assume a uniform distribution of fixations on objects. Here we propose to use object-based models that take a preferred viewing location (PVL) close to the centre of objects into account. In experiment 1, we demonstrate that, when including this comparably subtle modification, object-based models again are at par with state-of-the-art salience models in predicting fixations in natural scenes. One possible interpretation of these results is that objects rather than early salience dominate attentional guidance. In this view, early-salience models predict fixations through the correlation of their features with object locations. To test this hypothesis directly, in two additional experiments we reduced low-level salience in image areas of high object content. For these modified stimuli, the object-based model predicted fixations significantly better than early salience. This finding held in an object-naming task (experiment 2) and a free-viewing task (experiment 3). These results provide further evidence for object-based fixation selection – and by inference object-based attentional guidance – in natural scenes. 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-SA license

The coding of chronological order of real-life events, that is, “time’s arrow” in general event knowledge and its access in language comprehension was investigated with two relatedness judgment tasks. The temporal orientation (chronological or reverse) and the stimulus onset asynchrony (SOA; 200/250 ms or 1,000 ms) between preinformation and target were manipulated. The first experiment examined highly familiar sequences of events (e.g., lighting-burning-extinguishing) with the same strength of temporal relatedness for preceding and succeeding events. The second experiment investigated individual events. The results show that time’s arrow is not restricted to sequences of events, but is also embedded in the mental representation of individual events. The preferred temporal orientation in favor of future time is not only coded by a higher association strength between mental event representations, but also by expectancy based selection processes. The results support Barsalou’s model of perceptual symbol systems ( 1999 ).

Mathematical, models,have become an important tool for understanding the control of eye movements during reading. Main goals of the development of the SWIFT model (R. Engbert, A. Longtin, & R. Kliegl, 2002) were to investigate the possibility of spatially distributed processing and to implement a general mechanism for all types of eye movements observed in reading experiments. The authors present an advanced version of SWIFT that integrates properties of the oculomotor system and effects of word recognition to explain many of the experimental phenomena faced in reading research. They propose new procedures for the estimation of model parameters and for the test of the model's performance. They also present a mathematical analysis of the dynamics of the SWIFT model. Finally, within this framework, they present an analysis of the transition from parallel to serial processing

The influence of levels of abstraction in picture-word matching was examined. The items each consisted of one picture and three successively presented words. Hierarchies with words for superordinate, basic, and subordinate level concepts were used (e.g., plant, flower, rose). The picture-word condition (congruent, incongruent), the word position (first, second, third), and the level of categorization (subordinate, basic, superordinate) were manipulated. Reaction times, error rates, and pupillary responses were recorded. Pupillary responses coincided with behavioral data. In general, there was an advantage for subordinate and basic level processing compared to superordinate level processing. However, switches to words for superordinate concepts were most facilitated. These findings support a two-step account of picture-word matching. First, the picture is categorized according to its concrete features. Second, amodal features are processed.

Citation: Loschky, L. C., Nuthmann, A., Fortenbaugh, F. C., & Levi, D. M. (2017). Scene perception from central to peripheral vision. Journal of Vision, 17(1), 5. doi:10.1167/17.1.6

In two experiments we investigated the control of fixation durations in naturalistic scene viewing. Empirical evidence from the scene onset delay paradigm and numerical simulations of such data with the CRISP model [Psychological Review 117 (2010) 382–405] have suggested that processing related difficulties may lead to prolonged fixation durations. Here, we ask whether processing related facilitation may lead to comparable decreases to fixation durations. Research in visual search and reading have reported only uni-directional shifts. To address the question of unidirectional (slow down) as opposed to bidirectional (slow down and speed up) adjustment of fixation durations in the context of scene viewing, we used a saccade-contingent display change method to either reduce or increase the luminance of the scene during prespecified critical fixations. Degrading the stimulus by shifting luminance down resulted in an immediate increase to fixation durations. However, clarifying the stimulus by shifting luminance upwards did not result in a comparable decrease to fixation durations. These results suggest that the control of fixation durations in scene viewing is asymmetric, as has been reported for visual search and reading.

Research on scene categorization generally concentrates on gist processing, particularly the speed and minimal features with which the “story” of a scene can be extracted. However, this focus has led to a paucity of research into how scenes are categorized at specific hierarchical levels (e.g., a scene could be a road or more specifically a highway); consequently, research has disregarded a potential diagnostically driven feedback process. We presented participants with scenes that were low-pass filtered so only their gist was revealed, while a gaze-contingent window provided the fovea with full-resolution details. By recording where in a scene participants fixated prior to making a basic- or subordinate-level judgment, we identified the scene information accrued when participants made either categorization. We observed a feedback process, dependent on categorization level, that systematically accrues sufficient and detailed diagnostic information from the same scene. Our results demonstrate that during scene processing, a diagnostically driven bidirectional interplay between top-down and bottom-up information facilitates relevant category processing.

Summary. The present study used the technique of pupillometry to study whether pupillary changes are sensitive to variations in the processing of temporal order information in semantic memory. By employing two recognition tasks the temporal orientation (chronological vs. reverse) between pre-information and target was manipulated. The first experiment examined frequently occurring sequences of everyday events (e.g., cut - bleed - bandage) with the same strength of temporal relatedness for preceding and succeeding events. The second experiment investigated event-feature pairs (e.g., melt, solid - fluid) with temporal connectives (before, after). In addition to the psychological indicators reaction times and error rates two further psychophysiological indicators - maximum pupil diameters and dilatation times - were raised to validate the behavioral data. The results show that time’s arrow is not restricted to sequences of events, but also embedded in the mental representation of individual events. In both experiments psychophysiological indicators coincide with the psychological indicators. The pupillometric results provide additional new information: They indicate that the processing of temporal orientation towards future time does not only consume less time and produces less errors, but also that the processing is making less demands on mental resources. The presented study demonstrates that task-evoked pupillary response is a reliable and sensitive indicator for the experimental study of cognitive load.

An important factor constraining visual search performance is the inhomogeneity of the visual system. Engaging participants in a scene search task, the present study explored how the different regions of the visual field contribute to search. Gaze-contingent Blindspots and Spotlights were implemented to determine the absolute and relative importance of the different visual regions for object-in-scene search. Three Blindspot/Spotlight radii (1.6°, 2.9°, and 4.1°) were used to differentiate between foveal, parafoveal, and peripheral vision. When searching the scene with artificially impaired foveal or central vision (Blindspots), search performance was surprisingly unimpaired. Foveal vision was not necessary to attain normal search performance. When high-resolution scene information was withheld in both foveal and parafoveal vision (4.1° Blindspot), target localization was unimpaired but it took longer to verify the identity of the target. Artificially impairing extrafoveal scene analysis (Spotlights) affected attentional selection and visual processing; shrinking the Spotlight of high resolution led to longer search times, shorter saccades, and more and longer fixations. The 4.1° radius was identified as the crossover point of equal search times in Blindspot and Spotlight conditions. However, a gaze-data based decomposition of search times into behaviorally defined epochs revealed differences in particular subprocesses of search.

During natural scene viewing, humans typically attend and fixate selected locations for about 200–400 ms. Two variables characterize such ‘‘overt’’ attention: the probability of a location being fixated, and the fixation’s duration. Both variables have been widely researched, but little is known about their relation. We use a two- step approach to investigate the relation between fixation probability and duration. In the first step, we use a large corpus of fixation data. We demonstrate that fixation probability (empirical salience) predicts fixation duration across different observers and tasks. Linear mixed-effects modeling shows that this relation is explained neither by joint dependencies on simple image features (luminance, contrast, edge density) nor by spatial biases (central bias). In the second step, we experimentally manipulate some of these features. We find that fixation probability from the corpus data still predicts fixation duration for this new set of experimental data. This holds even if stimuli are deprived of low-level images features, as long as higher level scene structure remains intact. Together, this shows a robust relation between fixation duration and probability, which does not depend on simple image features. Moreover, the study exemplifies the combination of empirical research on a large corpus of data with targeted experimental manipulations.

Two contrasting views of visual attention in scenes are the visual salience and the cognitive relevance hypotheses. They fundamentally differ in their conceptualization of the visuospatial representation over which attention is directed. According to the saliency model, this representation is image-based, while the cognitive relevance framework advocates an object-based representation. Previous research has shown that (1) viewers prefer to look at objects over background and that (2) the saliency model predicts human fixation locations significantly better than chance. However, it could be that saliency mainly acts through objects. To test this hypothesis, we investigated where people fixate within real objects and saliency proto-objects. To this end, we recorded eye movements of human observers while they inspected photographs of natural scenes under different task instructions. We found a preferred viewing location (PVL) close to the center of objects within naturalistic scenes. Compared to the PVL for real objects, there was less evidence for a PVL for human fixations within saliency proto-objects. There was no evidence for a PVL when only saliency proto-objects that did not spatially overlap with annotated real objects were analyzed. The results suggest that saccade targeting and, by inference, attentional selection in scenes is object-based.

Eye-movement control during scene viewing can be represented as a series of individual decisions about where and when to move the eyes. While substantial behavioral and computational research has been devoted to investigating the placement of fixations in scenes, relatively little is known about the mechanisms that control fixation durations. Here, we propose a computational model (CRISP) that accounts for saccade timing and programming and thus for variations in fixation durations in scene viewing. First, timing signals are modeled as continuous-time random walks. Second, difficulties at the level of visual and cognitive processing can inhibit and thus modulate saccade timing. Inhibition generates moment-by-moment changes in the random walk’s transition rate and processing-related saccade cancellation. Third, saccade programming is completed in 2 stages: an initial, labile stage that is subject to cancellation and a subsequent, nonlabile stage. Several simulation studies tested the model’s adequacy and generality. An initial simulation study explored the role of cognitive factors in scene viewing by examining how fixation durations differed under different viewing task instructions. Additional simulations investigated the degree to which fixation durations were under direct moment-to-moment control of the current visual scene. The present work further supports the conclusion that fixation durations, to a certain degree, reflect perceptual and cognitive activity in scene viewing. Computational model simulations contribute to an understanding of the underlying processes of gaze control. (PsycINFO Database Record (c) 2012 APA, all rights reserved)