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- Balslev, Thomas, et al.
(författare)
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Visual Expertise In Paediatric Neurology
- 2012
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Ingår i: European Journal of Paediatric Neurology. - : Elsevier BV. - 1090-3798. ; 16, s. 161-166
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Tidskriftsartikel (refereegranskat)abstract
- Objective Visual expertise relies on perceptive as well as cognitive processes. At present, knowledge of these processes when diagnosing clinical cases mainly stems from studies with still pictures. Patient video cases constitute a dynamic and authentic, diagnostic challenge that may simulate seeing and diagnosing a patient in person. This study investigates visual attention and the concomitant cognitive processes of clinicians diagnosing authentic pediatric video cases. Methods A total of 43 clinicians with varying levels of expertise took part in this cross-sectional study. They diagnosed four brief video recordings of children: two with seizures and two with disorders imitating seizures. We used eye tracking to investigate time looking at relevant areas in the video cases and a concurrent think-aloud procedure to explore the associated clinical reasoning processes. Results More experienced clinicians were more accurate in visual diagnosis and spent more of their time looking at relevant areas. At the same time, they explored data less, yet they built and evaluated more diagnostic hypotheses. Interpretation This study adds a new perspective on medical expertise. More experienced clinicians (experts) focus better on relevant areas allowing them to explore data less and at the same time to build and evaluate more diagnostic hypotheses. The combination of effective visual search and the ability to effectively monitor for and evaluate different diagnostic options seems to characterize the experts in visual domains.
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- Dewhurst, Richard, et al.
(författare)
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How task demands influence scanpath similarity in a sequential number-search task
- 2018
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Ingår i: Vision Research. - : Elsevier BV. - 1878-5646 .- 0042-6989. ; , s. 9-23
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Tidskriftsartikel (refereegranskat)abstract
- More and more researchers are considering the omnibus eye movement sequence—the scanpath—in their studies of visual and cognitive processing (e.g. Hayes, Petrov, & Sederberg, 2011; Madsen, Larson, Loschky, & Rebello, 2012; Ni et al., 2011; von der Malsburg & Vasishth, 2011). However, it remains unclear how recent methods for comparing scanpaths perform in experiments producing variable scanpaths, and whether these methods supplement more traditional analyses of individual oculomotor statistics. We address this problem for MultiMatch (Jarodzka et al., 2010; Dewhurst et al., 2012), evaluating its performance with a visual search-like task in which participants must fixate a series of target numbers in a prescribed order. This task should produce predictable sequences of fixations and thus provide a testing ground for scanpath measures. Task difficulty was manipulated by making the targets more or less visible through changes in font and the presence of distractors or visual noise. These changes in task demands led to slower search and more fixations. Importantly, they also resulted in a reduction in the between-subjects scanpath similarity, demonstrating that participants’ gaze patterns became more heterogenous in terms of saccade length and angle, and fixation position. This implies a divergent strategy or random component to eye-movement behaviour which increases as the task becomes more difficult. Interestingly, the duration of fixations along aligned vectors showed the opposite pattern, becoming more similar between observers in 2 of the 3 difficulty manipulations. This provides important information for vision scientists who may wish to use scanpath metrics to quantify variations in gaze across a spectrum of perceptual and cognitive tasks. © 2018 Elsevier Ltd
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| 5. |
- Dewhurst, Richard, et al.
(författare)
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It depends on how you look at it: Scanpath comparison in multiple dimensions with MultiMatch, a vector-based approach
- 2012
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Ingår i: Behavior Research Methods. - : Springer Science and Business Media LLC. - 1554-3528.
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Tidskriftsartikel (refereegranskat)abstract
- Eye movement sequences---or scanpaths---vary depending on stimulus characteristics and task (Foulsham \& Underwood, 2008; Land, Mennie, \& Rusted, 1999). Common methods for comparing scanpaths, however, are limited in their ability to capture both the spatial and temporal properties of which a scanpath consists. Here we validate a new method for scanpath comparison based on geometric vectors, which compares scanpaths over multiple dimensions retaining positional and sequential information (Jarodzka, Holmqvist, \& Nyström, 2010). `MultiMatch' was tested in two experiments and pitted against ScanMatch (Cristino, Mathôt, Theeuwes, \& Gilchrist, 2010), the most comprehensive adaptation of the popular Levenshtein method. Experiment 1 used synthetic data, demonstrating the greater sensitivity of MultiMatch to variations in spatial position. In experiment 2 real eye movement recordings were taken from participants viewing sequences of dots, designed to elicit scanpath pairs with commonalities known to be problematic for algorithms (for example, when one scanpath is shifted in locus, or fixations fall either side of an AOI boundary). Results illustrate the advantages of a multidimensional approach, revealing how two scanpath differ. For instance, if one scanpath is the reverse copy of another the difference is in direction but not the position of fixations; or if a scanpath is scaled down, the difference is in the length of saccadic vectors but not overall shape. As well as having enormous potential for any task in which consistency in eye movements is important (e.g. learning), MultiMatch is particularly relevant for "eye movements to nothing" in mental imagery research and embodiment of cognition, where satisfactory scanpath comparison algorithms are lacking.
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| 8. |
- Emhardt, Selina N., et al.
(författare)
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What is my teacher talking about? Effects of displaying the teacher’s gaze and mouse cursor cues in video lectures on students’ learning
- 2022
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Ingår i: Journal of Cognitive Psychology. - : Informa UK Limited. - 2044-5911 .- 2044-592X. ; 34:7, s. 846-864
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Tidskriftsartikel (refereegranskat)abstract
- Eye movement modelling examples (EMME) are instructional videos that display a teacher’s eye movements as “gaze cursor” (e.g. a moving dot) superimposed on the learning task. This study investigated if previous findings on the beneficial effects of EMME would extend to online lecture videos and compared the effects of displaying the teacher’s gaze cursor with displaying the more traditional mouse cursor as a tool to guide learners’ attention. Novices (N = 124) studied a pre-recorded video lecture on how to model business processes in a 2 (mouse cursor absent/present) × 2 (gaze cursor absent/present) between-subjects design. Unexpectedly, we did not find significant effects of the presence of gaze or mouse cursors on mental effort and learning. However, participants who watched videos with the gaze cursor found it easier to follow the teacher. Overall, participants responded positively to the gaze cursor, especially when the mouse cursor was not displayed in the video.
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| 9. |
- Foulsham, Thomas, et al.
(författare)
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Comparing scanpaths during scene encoding and recognition: A multi-dimensional approach
- 2012
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Ingår i: Journal of Eye Movement Research. - 1995-8692. ; 5:4:3, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- Abstract in UndeterminedComplex stimuli and tasks elicit particular eye movement sequences. Previous research has focused on comparing between these scanpaths, particularly in memory and imagery research where it has been proposed that observers reproduce their eye movements when recognizing or imagining a stimulus. However, it is not clear whether scanpath similarity is related to memory performance and which particular aspects of the eye movements recur. We therefore compared eye movements in a picture memory task, using a recently proposed comparison method, MultiMatch, which quantifies scanpath similarity across multiple dimensions including shape and fixation duration. Scanpaths were more similar when the same participant's eye movements were compared from two viewings of the same image than between different images or different participants viewing the same image. In addition, fixation durations were similar within a participant and this similarity was associated with memory performance.
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| 10. |
- Holmqvist, Kenneth, et al.
(författare)
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Eye Tracking : A Comprehensive Guide to Methods and Measures
- 2011
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- This book is written by and for researchers who are still in that part of their careers where they are actively using the eye-tracker as a tool; those who have to deal with the technology, the signals, the filters, the algorithms, the experimental design, the programming of stimulus presentation, instructions to participants, working the varying tools for data analysis, and of course, worrying about all the different things that must not go wrong! A central theme of the book concerns the wide range of fields eye tracking covers. Suppose an educational psychologist wishes to use eye tracking to evaluate a new software pack- age designed to support learning to read. She may have an excellent idea as a starting point, and some understanding of the kind of results eye tracking could provide to tackle her re- search question, but unless she and the group around her are also adept in computer science, it is unlikely she will know how the eye movement data she collects is generated: How raw data samples are converted into fixations and saccades using event detection algorithms, how the different representations of eye movement data are calculated, and how all the measures of eye movements relate to these processes. All this is important because subtleties involved in working with eye-tracking data can have large consequences for the final results, and thus whether our educational psychologist can confidently conclude that her software package is effective or not in supporting the development of reading skills. This is not to say that hard-core computer science skills are the crux of good eye-tracking research, for this is certainly not the case. One can equally envisage a situation where an expert in programming and the manipulation of data plans and executes an eye-tracking study poorly, simply because she is not trained in the principles of experimental design, and the associated literature on the visual system and oculomotor control. There are many contrasts between the diverging schools of thought which use eye track- ing; practices and preferences vary, but certainly experts in different fields do not draw on each other’s strengths enough. We felt there was a need to pinpoint the relative merits of adopting methods based in one field alone, whilst highlighting that the lack of synergy be- tween different disciplines can lead to sub-optimal research practices, and new advancements being overlooked. Besides technical details and theory, however, the heart of this book revolves around practicality. At the Humanities Laboratory at Lund University we have been teaching eye- tracking methodology regularly since 2000. We commonly see newcomers to the technique run aground when encountering just the sort of issues raised above, but beginners struggle with problems which are even more practical in nature. Hands-on advice for how to actually use eye-trackers is very limited. Setting up the eye camera and performing a good calibration routine is just as important as the design of the study and how data is handled, for if the recording is poor your options are limited from the outset. There are fundamental methodological skills which underpin using eye-trackers, but at the other end of the spectrum there is also the vast choice of measures available to the eye-tracking researcher. For the present text to be complete, therefore, we felt a require- ment should also be to draw together eye-tracking measures, as well as methods, into an understandable structure. So, starting around 2005, we began producing a taxonomy of all eye-movement methods and measures used by researchers, examining how the measures are related to each other, what type of data quality they rely on, and previous data processing they require. Our classification work thus consisted of searching the method sections from thousands of journal papers, book chapters, PhD theses and conference proceedings. Every measure and method we found was catalogued and put into a growing system. Some of the measures were extremely elusive, as they are known by different names, not only between research fields, but even within, and often the precise implementations are missing in the WHY WE WROTE THIS BOOK | v vi | WHY WE WROTE THIS BOOK published texts. At first, we were very unclear how to classify measures. Some varieties of taxonomic structures that we rejected can be found on p. 463. We ended up with a classifica- tion structure where the operational definitions are at the centre. Users of eye-trackers often lack proficient training because there is little or no teaching community to rely on. As a result people are often self taught, or depend on second-hand knowledge which may be out of date or even incorrect. When they participate in our eye- tracking methodology courses, we find that many new users are very focused on their re- search questions, but are surprised how much time they need to invest in order to master eye tracking properly. Often people attending have just purchased an eye-tracker to compliment their research, or for use in their company to tackle ergonomic and marketing-related ques- tions. Our aim for this book is to make learning to use eye-trackers a much easier process for these readers. If you have a solid background in experimental psychology, computer sci- ence, or mathematics you will often find it straightforward to embrace the technologies and workflows surrounding eye tracking. But whatever your background, you should be able to achieve the same level of knowledge and understanding from this book as you would from training on eye tracking in-house in a fully competent laboratory. More specifically, this book has been written to be a support when: 1. Evaluating or acquiring a commercial eye-tracker, 2. Planning an experiment where eye tracking is used as a tool, 3. About to record eye-movement data, 4. Planning how to process and interpret the recorded data, before carrying out statistical tests on it, 5. Reading or reviewing eye-movement research. In our efforts to classify eye-tracking methods and measures, combined with useful prac- tical hints and tips, we hope to provide the reader with the first comprehensive textbook on methodology for new users of eye tracking, but which also caters for the advanced researcher. Previous versions of this book have been used in eye-tracking education in Lund. Also, col- leagues of ours in Potsdam, Tübingen, and Helsinki have used earlier manuscripts of the book when teaching and training masters and PhD level students in eye tracking. Lastly, although not the target audience, manufacturers have already shown a great interest in the book at the manuscript stage, which we hope may lead to even better eye-trackers in the future.
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