Gaze patterns reflect and predict expertise in dynamic echocardiographic imaging.

Purpose: Echocardiography is the most important modality in cardiac imaging. Rapid valid visual assessment is a critical skill for image interpretation. However, it is unclear how skilled viewers assess echocardiographic images. Therefore, guidance and implicit advice are needed for learners to achieve valid image interpretation. Approach: Using a signal detection approach, we compared 15 certified experts with 15 medical students in their diagnostic decision-making and viewing behavior. To quantify attention allocation, we recorded eye movements while viewing dynamic echocardiographic imaging loops of patients with reduced ejection fraction and healthy controls. Participants evaluated left ventricular ejection fraction and image quality (as diagnostic and visual control tasks, respectively). Results: Experts were much better at discriminating between patients and healthy controls ( d ' of 2.58, versus 0.98 for novices). Eye tracking revealed that experts fixated diagnostically relevant areas earlier and more often, whereas novices were distracted by visually salient task-irrelevant stimuli. We show that expertise status can be almost perfectly classified either based on judgments or purely on eye movements and that an expertise score derived from viewing behavior predicts diagnostic quality. Conclusions: Judgments and eye tracking revealed significant differences between echocardiography experts and novices that can be used to derive numerical expertise scores. Experts have implicitly learned to ignore the salient motion cue presented by the mitral valve and to focus on the diagnostically more relevant left ventricle. These findings have implications for echocardiography training, objective characterization of echocardiographic expertise, and the design of user-friendly interfaces for echocardiography.

Cognitive reserve and the risk of postoperative neurocognitive disorders in older age.

Background: Postoperative delirium (POD) and postoperative cognitive dysfunction (POCD) are postoperative neurocognitive disorders (PNDs) that frequently occur in the aftermath of a surgical intervention. Cognitive reserve (CR) is a concept posited to explain why cognitive health varies between individuals. On this qualitative understanding of cognitive health, factors like IQ, education level, and occupational complexity can affect the impact of neuropathological processes on cognitive outcomes. Methods: We investigated the association between CR and POD and CR and POCD on data from 713 patients aged≥65 years with elective surgery. Peak pre-morbid IQ was estimated from vocabulary. Occupational complexity was coded according to the Dictionary of Occupational Titles (DOT). Education level was classed according to the International Standard Classification of Education (ISCED). These three factors were used as proxies of CR. In a series of regression models, age, sex, depression, site of surgery, and several lifestyle and vascular factors were controlled for. Results: Patients with a higher IQ had lower odds of developing POD. We found no significant association between the other two CR markers with POD. None of the CR markers was associated with POCD. Conclusion: The significant association of a higher IQ with lower POD risk allows for the stratification of elderly surgical patients by risk. This knowledge can aid the prevention and/or early detection of POD. Further research should attempt to determine the lack of associations of CR markers with POCD in our study.

The perceptual span is dynamically adjusted in response to foveal load by beginning readers.

The perceptual span describes the size of the visual field from which information is obtained during a fixation in reading. Its size depends on characteristics of writing system and reader, but-according to the foveal load hypothesis-it is also adjusted dynamically as a function of lexical processing difficulty. Using the moving window paradigm to manipulate the amount of preview, here we directly test whether the perceptual span shrinks as foveal word difficulty increases. We computed the momentary size of the span from word-based eye-movement measures as a function of foveal word frequency, allowing us to separately describe the perceptual span for information affecting spatial saccade targeting and temporal saccade execution. First fixation duration and gaze duration on the upcoming (parafoveal) word N + 1 were significantly shorter when the current (foveal) word N was more frequent. We show that the word frequency effect is modulated by window size. Fixation durations on word N + 1 decreased with high-frequency words N, but only for large windows, that is, when sufficient parafoveal preview was available. This provides strong support for the foveal load hypothesis. To investigate the development of the foveal load effect, we analyzed data from three waves of a longitudinal study on the perceptual span with German children in Grades 1 to 6. Perceptual span adjustment emerged early in development at around second grade and remained stable in later grades. We conclude that the local modulation of the perceptual span indicates a general cognitive process, perhaps an attentional gradient with rapid readjustment. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Semantic preview benefit and cost: Evidence from parafoveal fast-priming paradigm.

How is semantic information in the mental lexicon accessed and selected during reading? Readers process information of both the foveal and parafoveal words. Recent eye-tracking studies hint at bi-phasic lexical activation dynamics, demonstrating that semantically related parafoveal previews can either facilitate, or interfere with lexical processing of target words in comparison to unrelated previews, with the size and direction of the effect depending on exposure time to parafoveal previews. However, evidence to date is only correlational, because exposure time was determined by participants' pre-target fixation durations. Here we experimentally controlled parafoveal preview exposure duration using a combination of the gaze-contingent fast-priming and boundary paradigms. We manipulated preview duration and examined the time course of parafoveal semantic activation during the oral reading of Chinese sentences in three experiments. Semantic previews led to faster lexical access of target words than unrelated previews only when the previews were presented briefly (80 ms in Experiments 1 and 3). Longer exposure time (100 ms or 150 ms) eliminated semantic preview effects, and full preview without duration limit resulted in preview cost, i.e., a reversal of preview benefit. Our results indicate that high-level semantic information can be obtained from parafoveal words and the size and direction of the parafoveal semantic effect depends on the level of lexical activation.

A biological foundation for spatial-numerical associations: the brain's asymmetric frequency tuning.

"Left" and "right" coordinates control our spatial behavior and even influence abstract thoughts. For number concepts, horizontal spatial-numerical associations (SNAs) have been widely documented: we associate few with left and many with right. Importantly, increments are universally coded on the right side even in preverbal humans and nonhuman animals, thus questioning the fundamental role of directional cultural habits, such as reading or finger counting. Here, we propose a biological, nonnumerical mechanism for the origin of SNAs on the basis of asymmetric tuning of animal brains for different spatial frequencies (SFs). The resulting selective visual processing predicts both universal SNAs and their context-dependence. We support our proposal by analyzing the stimuli used to document SNAs in newborns for their SF content. As predicted, the SFs contained in visual patterns with few versus many elements preferentially engage right versus left brain hemispheres, respectively, thus predicting left-versus rightward behavioral biases. Our "brain's asymmetric frequency tuning" hypothesis explains the perceptual origin of horizontal SNAs for nonsymbolic visual numerosities and might be extensible to the auditory domain.

Computational Approaches to Comics Analysis.

Comics are complex documents whose reception engages cognitive processes such as scene perception, language processing, and narrative understanding. Possibly because of their complexity, they have rarely been studied in cognitive science. Modeling the stimulus ideally requires a formal description, which can be provided by feature descriptors from computer vision and computational linguistics. With a focus on document analysis, here we review work on the computational modeling of comics. We argue that the development of modern feature descriptors based on deep learning techniques has made sufficient progress to allow the investigation of complex material such as comics for reception studies, including experimentation and computational modeling of cognitive processes.

How spatial frequencies and color drive object search in real-world scenes: A new eye-movement corpus.

When studying how people search for objects in scenes, the inhomogeneity of the visual field is often ignored. Due to physiological limitations, peripheral vision is blurred and mainly uses coarse-grained information (i.e., low spatial frequencies) for selecting saccade targets, whereas high-acuity central vision uses fine-grained information (i.e., high spatial frequencies) for analysis of details. Here we investigated how spatial frequencies and color affect object search in real-world scenes. Using gaze-contingent filters, we attenuated high or low frequencies in central or peripheral vision while viewers searched color or grayscale scenes. Results showed that peripheral filters and central high-pass filters hardly affected search accuracy, whereas accuracy dropped drastically with central low-pass filters. Peripheral filtering increased the time to localize the target by decreasing saccade amplitudes and increasing number and duration of fixations. The use of coarse-grained information in the periphery was limited to color scenes. Central filtering increased the time to verify target identity instead, especially with low-pass filters. We conclude that peripheral vision is critical for object localization and central vision is critical for object identification. Visual guidance during peripheral object localization is dominated by low-frequency color information, whereas high-frequency information, relatively independent of color, is most important for object identification in central vision.

Eye movements in developing readers: From basic research to classroom application. Parts of symposium 7 at the 20th European Conference on Eye Movements in Alicante, September 21, 2019.

Eye-movement recording has made it possible to achieve a detailed understanding of oculomotor and cognitive behavior during reading and of changes in this behavior across the stages of reading development. Given that many students struggle to attain even basic reading skills, a logical extension of eye-movement research involves its applications in both the diagnostic and instructional areas of reading education. The focus of this symposium is on eye-movement research with potential implications for reading education. Christian Vorstius will review results from a large-scale longitudinal study that examined the development of spatial parameters in fixation patterns within three cohorts, ranging from elementary to early middle school, discussing an early development window and its potential influences on reading ability and orthography. Ronan Reilly and Xi Fan will present longitudinal data related to developmental changes in reading-related eye movements in Chinese. Their findings are indicative of increasing sensitivity to lexical predictability and sentence coherence. The authors suggest that delays in the emergence of these reading behaviors may signal early an increased risk of reading difficulty. Jochen Laubrock's presentation will focus on perceptual span development and explore dimensions of this phenomenon with potential educational implications, such as the modulation of perceptual span in relation to cognitive load, as well as preview effects during oral and silent reading --and while reading comic books. Video stream: https://vimeo.com/362645755.

Gaze-contingent manipulation of the FVF demonstrates the importance of fixation duration for explaining search behavior.

Hulleman & Olivers' (H&O's) model introduces variation of the functional visual field (FVF) for explaining visual search behavior. Our research shows how the FVF can be studied using gaze-contingent displays and how FVF variation can be implemented in models of gaze control. Contrary to H&O, we believe that fixation duration is an important factor when modeling visual search behavior.

The visual number world: A dynamic approach to study the mathematical mind.

In the domain of language research, the simultaneous presentation of a visual scene and its auditory description (i.e., the visual world paradigm) has been used to reveal the timing of mental mechanisms. Here we apply this rationale to the domain of numerical cognition in order to explore the differences between fast and slow arithmetic performance, and to further study the role of spatial-numerical associations during mental arithmetic. We presented 30 healthy adults simultaneously with visual displays containing four numbers and with auditory addition and subtraction problems. Analysis of eye movements revealed that participants look spontaneously at the numbers they currently process (operands, solution). Faster performance was characterized by shorter latencies prior to fixating the relevant numbers and fewer revisits to the first operand while computing the solution. These signatures of superior task performance were more pronounced for addition and visual numbers arranged in ascending order, and for subtraction and numbers arranged in descending order (compared to the opposite pairings). Our results show that the "visual number world"-paradigm provides on-line access to the mind during mental arithmetic, is able to capture variability in arithmetic performance, and is sensitive to visual layout manipulations that are otherwise not reflected in response time measurements.

Spatial frequency processing in the central and peripheral visual field during scene viewing.

Visuospatial attention and gaze control depend on the interaction of foveal and peripheral processing. The foveal and peripheral regions of the visual field are differentially sensitive to parts of the spatial-frequency spectrum. In two experiments, we investigated how the selective attenuation of spatial frequencies in the central or the peripheral visual field affects eye-movement behavior during real-world scene viewing. Gaze-contingent low-pass or high-pass filters with varying filter levels (i.e., cutoff frequencies; Experiment 1) or filter sizes (Experiment 2) were applied. Compared to unfiltered control conditions, mean fixation durations increased most with central high-pass and peripheral low-pass filtering. Increasing filter size prolonged fixation durations with peripheral filtering, but not with central filtering. Increasing filter level prolonged fixation durations with low-pass filtering, but not with high-pass filtering. These effects indicate that fixation durations are not always longer under conditions of increased processing difficulty. Saccade amplitudes largely adapted to processing difficulty: amplitudes increased with central filtering and decreased with peripheral filtering; the effects strengthened with increasing filter size and filter level. In addition, we observed a trade-off between saccade timing and saccadic selection, since saccade amplitudes were modulated when fixation durations were unaffected by the experimental manipulations. We conclude that interactions of perception and gaze control are highly sensitive to experimental manipulations of input images as long as the residual information can still be accessed for gaze control.

Coupling of attention and saccades when viewing scenes with central and peripheral degradation.

Degrading real-world scenes in the central or the peripheral visual field yields a characteristic pattern: Mean saccade amplitudes increase with central and decrease with peripheral degradation. Does this pattern reflect corresponding modulations of selective attention? If so, the observed saccade amplitude pattern should reflect more focused attention in the central region with peripheral degradation and an attentional bias toward the periphery with central degradation. To investigate this hypothesis, we measured the detectability of peripheral (Experiment 1) or central targets (Experiment 2) during scene viewing when low or high spatial frequencies were gaze-contingently filtered in the central or the peripheral visual field. Relative to an unfiltered control condition, peripheral filtering induced a decrease of the detection probability for peripheral but not for central targets (tunnel vision). Central filtering decreased the detectability of central but not of peripheral targets. Additional post hoc analyses are compatible with the interpretation that saccade amplitudes and direction are computed in partial independence. Our experimental results indicate that task-induced modulations of saccade amplitudes reflect attentional modulations.

Development of the perceptual span in reading: A longitudinal study.

The perceptual span is a standard measure of parafoveal processing, which is considered highly important for efficient reading. Is the perceptual span a stable indicator of reading performance? What drives its development? Do initially slower and faster readers converge or diverge over development? Here we present the first longitudinal data on the development of the perceptual span in elementary school children. Using the moving window technique, eye movements of 127 German children in three age groups (Grades 1, 2, and 3 in Year 1) were recorded at two time points (T1 and T2) 1 year apart. Introducing a new measure of the perceptual span, nonlinear mixed-effects modeling was used to separate window size effects from asymptotic reading performance. Cross-sectional differences were well replicated longitudinally. Asymptotic reading rate increased monotonously with grade, but in a decelerating fashion. A significant change in the perceptual span was observed only between Grades 2 and 3. Together with results from a cross-lagged panel model, this suggests that the perceptual span increases as a consequence of relatively well-established word reading. Stabilities of observed and predicted reading rates were high after Grade 1, whereas the perceptual span was only moderately stable for all grades. Comparing faster and slower readers as assessed at T1, in general, a pattern of stable between-group differences emerged rather than a compensatory pattern; second and third graders even showed a Matthew effect in reading rate and the perceptual span, respectively.

Parafoveal processing in silent and oral reading: Reading mode influences the relative weighting of phonological and semantic information in Chinese.

We examined how reading mode (i.e., silent vs. oral reading) influences parafoveal semantic and phonological processing during the reading of Chinese sentences, using the gaze-contingent boundary paradigm. In silent reading, we found in 2 experiments that reading times on target words were shortened with semantic previews in early and late processing, whereas phonological preview effects mainly occurred in gaze duration or second-pass reading. In contrast, results showed that phonological preview information is obtained early on in oral reading. Strikingly, in oral reading, we observed a semantic preview cost on the target word in Experiment 1 and a decrease in the effect size of preview benefit from first- to second-pass measures in Experiment 2, which we hypothesize to result from increased preview duration. Taken together, our results indicate that parafoveal semantic information can be obtained irrespective of reading mode, whereas readers more efficiently process parafoveal phonological information in oral reading. We discuss implications for notions of information processing priority and saccade generation during silent and oral reading. (PsycINFO Database Record

The eye-voice span during reading aloud.

Although eye movements during reading are modulated by cognitive processing demands, they also reflect visual sampling of the input, and possibly preparation of output for speech or the inner voice. By simultaneously recording eye movements and the voice during reading aloud, we obtained an output measure that constrains the length of time spent on cognitive processing. Here we investigate the dynamics of the eye-voice span (EVS), the distance between eye and voice. We show that the EVS is regulated immediately during fixation of a word by either increasing fixation duration or programming a regressive eye movement against the reading direction. EVS size at the beginning of a fixation was positively correlated with the likelihood of regressions and refixations. Regression probability was further increased if the EVS was still large at the end of a fixation: if adjustment of fixation duration did not sufficiently reduce the EVS during a fixation, then a regression rather than a refixation followed with high probability. We further show that the EVS can help understand cognitive influences on fixation duration during reading: in mixed model analyses, the EVS was a stronger predictor of fixation durations than either word frequency or word length. The EVS modulated the influence of several other predictors on single fixation durations (SFDs). For example, word-N frequency effects were larger with a large EVS, especially when word N-1 frequency was low. Finally, a comparison of SFDs during oral and silent reading showed that reading is governed by similar principles in both reading modes, although EVS maintenance and articulatory processing also cause some differences. In summary, the EVS is regulated by adjusting fixation duration and/or by programming a regressive eye movement when the EVS gets too large. Overall, the EVS appears to be directly related to updating of the working memory buffer during reading.

Incidental sequence learning in a motion coherence discrimination task: How response learning affects perception.

The serial reaction time task (SRTT) is a standard task used to investigate incidental sequence learning. Whereas incidental learning of motor sequences is well-established, few and disputed results support learning of perceptual sequences. Here we adapt a motion coherence discrimination task (Newsome & Paré, 1988) to the sequence learning paradigm. The new task has 2 advantages: (a) the stimulus is presented at fixation, thereby obviating overt eye movements, and (b) by varying coherence a perceptual threshold measure is available in addition to the performance measure of RT. Results from 3 experiments show that action relevance of the sequence is necessary for sequence learning to occur, that the amount of sequence knowledge varies with the ease of encoding the motor sequence, and that sequence knowledge, once acquired, has the ability to modify perceptual thresholds.

Registering eye movements during reading in Alzheimer's disease: difficulties in predicting upcoming words.

Reading requires the fine integration of attention, ocular movements, word identification, and language comprehension, among other cognitive parameters. Several of the associated cognitive processes such as working memory and semantic memory are known to be impaired by Alzheimer's disease (AD). This study analyzes eye movement behavior of 18 patients with probable AD and 40 age-matched controls during Spanish sentence reading. Controls focused mainly on word properties and considered syntactic and semantic structures. At the same time, controls' knowledge and prediction about sentence meaning and grammatical structure are quite evident when we consider some aspects of visual exploration, such as word skipping, and forward saccades. By contrast, in the AD group, the predictability effect of the upcoming word was absent, visual exploration was less focused, fixations were much longer, and outgoing saccade amplitudes were smaller than those in controls. The altered visual exploration and the absence of a contextual predictability effect might be related to impairments in working memory and long-term memory retrieval functions. These eye movement measures demonstrate considerable sensitivity with respect to evaluating cognitive processes in Alzheimer's disease. They could provide a user-friendly marker of early disease symptoms and of its posterior progression.

Interoceptive focus shapes the experience of time.

The perception of time is a fundamental part of human experience. Recent research suggests that the experience of time emerges from emotional and interoceptive (bodily) states as processed in the insular cortex. Whether there is an interaction between the conscious awareness of interoceptive states and time distortions induced by emotions has rarely been investigated so far. We aimed to address this question by the use of a retrospective time estimation task comparing two groups of participants. One group had a focus on interoceptive states and one had a focus on exteroceptive information while watching film clips depicting fear, amusement and neutral content. Main results were that attention to interoceptive processes significantly affected subjective time experience. Fear was accompanied with subjective time dilation that was more pronounced in the group with interoceptive focus, while amusement led to a quicker passage of time which was also increased by interoceptive focus. We conclude that retrospective temporal distortions are directly influenced by attention to bodily responses. These effects might crucially interact with arousal levels. Sympathetic nervous system activation affecting memory build-up might be the decisive factor influencing retrospective time judgments. Our data substantially extend former research findings underscoring the relevance of interoception for the effects of emotional states on subjective time experience.