Jarodzka, H., Balslev, T., Holmqvist, K., Nyström, M., Scheiter, K., Gerjets, P., & E... more Jarodzka, H., Balslev, T., Holmqvist, K., Nyström, M., Scheiter, K., Gerjets, P., & Eika, B. (2011, April). Fostering perceptual skills in medical diagnosis. Meeting of the American Educational Research Association, New Orleans, USA. ... Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.
Event detection is used to classify recorded gaze points into periods of fixation, saccade, smoot... more Event detection is used to classify recorded gaze points into periods of fixation, saccade, smooth pursuit, blink, and noise. Although there is an overall consensus that current algorithms for event detection have serious flaws and that a de facto standard for event detection does not exist, surprisingly little work has been done to remedy this problem. We suggest a new velocity-based algorithm that takes several of the previously known limitations into account. Most important, the new algorithm identifies so-called glissades, a wobbling movement at the end of many saccades, as a separate class of eye movements. Part of the solution involves designing an adaptive velocity threshold that makes the event detection less sensitive to variations in noise level and the algorithm settings-free for the user. We demonstrate the performance of the new algorithm on eye movements recorded during reading and scene perception and compare it with two of the most commonly used algorithms today. Results show that, unlike the currently used algorithms, fixations, saccades, and glissades are robustly identified by the new algorithm. Using this algorithm, we found that glissades occur in about half of the saccades, during both reading and scene perception, and that they have an average duration close to 24 msec. Due to the high prevalence and long durations of glissades, we argue that researchers must actively choose whether to assign the glissades to saccades or fixations; the choice affects dependent variables such as fixation and saccade duration significantly. Current algorithms do not offer this choice, and their assignments of each glissade are largely arbitrary.
Visual expertise relies on perceptive as well as cognitive processes. At present, knowledge of th... more 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. In contrast, patient video cases constitute a dynamic 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 paediatric video cases.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.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.Clinicians of varying expertise analyse patient video cases differently. Clinical teachers should take these differences into account when optimising educational formats with patient video cases.► We examined eye movements and think-aloud in clinicians analysing video cases. ► Clinicians of varying expertise analysed patient video cases differently. ► More experienced clinicians looked more at relevant areas. ► More experienced clinicians were more accurate in visual diagnosis. ► More experienced clinicians built and evaluated more diagnostic hypotheses.
This study provides evidence that eye movements reflect the positions of objects while participan... more This study provides evidence that eye movements reflect the positions of objects while participants listen to a spoken description, retell a previously heard spoken description, and describe a previously seen picture. This effect is equally strong in retelling from memory, irrespective of whether the original elicitation was spoken or visual. In addition, this effect occurs both while watching a blank white board and while sitting in complete darkness. This study includes 4 experiments. The first 2 experiments measured eye movements of participants looking at a blank white board. Experiment 1 monitors eye movements of participants on 2 occasions: first, when participants listened to a prerecorded spoken scene description; second, when participants were later retelling it from memory. Experiment 2 first monitored eye movements of participants as they studied a complex picture visually, and then later as they described it from memory. The second pair of experiments (Experiments 3 and 4) replicated Experiments 1 and 2 with the only difference being that they were executed in complete darkness. This method of analysis differentiated between eye movements that are categorically correct relative to the positions of the whole eye gaze pattern (global correspondence) and eye movements that are only locally correct (local correspondence). The discussion relates the findings to the current debate on mental imagery.
Writers typically spend a certain proportion of time looking back over the text that they have wr... more Writers typically spend a certain proportion of time looking back over the text that they have written. This is likely to serve a number of different functions, which are currently poorly understood. In this article, we present two systems, ScriptLog+TimeLine and EyeWrite, that adopt different and complementary approaches to exploring this activity by collecting and analyzing combined eye movement and keystroke data from writers composing extended texts. ScriptLog+TimeLine is a system that is based on an existing keystroke-logging program and uses heuristic, pattern-matching methods to identify reading episodes within eye movement data. EyeWrite is an integrated editor and analysis system that permits identification of the words that the writer fixates and their location within the developing text. We demonstrate how the methods instantiated within these systems can be used to make sense of the large amount of data generated by eyetracking and keystroke logging in order to inform understanding of the cognitive processes that underlie written text production.
... and a total response index (depth index as a percentage times the number of readers). ... the... more ... and a total response index (depth index as a percentage times the number of readers). ... the importance of designing the newspaper layout so that it quickly leads the reader to the ... The subjects (experienced users of online newspaper sites) were asked to read in the manner they ...
Jarodzka, H., Balslev, T., Holmqvist, K., Nyström, M., Scheiter, K., Gerjets, P., & E... more Jarodzka, H., Balslev, T., Holmqvist, K., Nyström, M., Scheiter, K., Gerjets, P., & Eika, B. (2011, April). Fostering perceptual skills in medical diagnosis. Meeting of the American Educational Research Association, New Orleans, USA. ... Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.
Event detection is used to classify recorded gaze points into periods of fixation, saccade, smoot... more Event detection is used to classify recorded gaze points into periods of fixation, saccade, smooth pursuit, blink, and noise. Although there is an overall consensus that current algorithms for event detection have serious flaws and that a de facto standard for event detection does not exist, surprisingly little work has been done to remedy this problem. We suggest a new velocity-based algorithm that takes several of the previously known limitations into account. Most important, the new algorithm identifies so-called glissades, a wobbling movement at the end of many saccades, as a separate class of eye movements. Part of the solution involves designing an adaptive velocity threshold that makes the event detection less sensitive to variations in noise level and the algorithm settings-free for the user. We demonstrate the performance of the new algorithm on eye movements recorded during reading and scene perception and compare it with two of the most commonly used algorithms today. Results show that, unlike the currently used algorithms, fixations, saccades, and glissades are robustly identified by the new algorithm. Using this algorithm, we found that glissades occur in about half of the saccades, during both reading and scene perception, and that they have an average duration close to 24 msec. Due to the high prevalence and long durations of glissades, we argue that researchers must actively choose whether to assign the glissades to saccades or fixations; the choice affects dependent variables such as fixation and saccade duration significantly. Current algorithms do not offer this choice, and their assignments of each glissade are largely arbitrary.
Visual expertise relies on perceptive as well as cognitive processes. At present, knowledge of th... more 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. In contrast, patient video cases constitute a dynamic 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 paediatric video cases.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.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.Clinicians of varying expertise analyse patient video cases differently. Clinical teachers should take these differences into account when optimising educational formats with patient video cases.► We examined eye movements and think-aloud in clinicians analysing video cases. ► Clinicians of varying expertise analysed patient video cases differently. ► More experienced clinicians looked more at relevant areas. ► More experienced clinicians were more accurate in visual diagnosis. ► More experienced clinicians built and evaluated more diagnostic hypotheses.
This study provides evidence that eye movements reflect the positions of objects while participan... more This study provides evidence that eye movements reflect the positions of objects while participants listen to a spoken description, retell a previously heard spoken description, and describe a previously seen picture. This effect is equally strong in retelling from memory, irrespective of whether the original elicitation was spoken or visual. In addition, this effect occurs both while watching a blank white board and while sitting in complete darkness. This study includes 4 experiments. The first 2 experiments measured eye movements of participants looking at a blank white board. Experiment 1 monitors eye movements of participants on 2 occasions: first, when participants listened to a prerecorded spoken scene description; second, when participants were later retelling it from memory. Experiment 2 first monitored eye movements of participants as they studied a complex picture visually, and then later as they described it from memory. The second pair of experiments (Experiments 3 and 4) replicated Experiments 1 and 2 with the only difference being that they were executed in complete darkness. This method of analysis differentiated between eye movements that are categorically correct relative to the positions of the whole eye gaze pattern (global correspondence) and eye movements that are only locally correct (local correspondence). The discussion relates the findings to the current debate on mental imagery.
Writers typically spend a certain proportion of time looking back over the text that they have wr... more Writers typically spend a certain proportion of time looking back over the text that they have written. This is likely to serve a number of different functions, which are currently poorly understood. In this article, we present two systems, ScriptLog+TimeLine and EyeWrite, that adopt different and complementary approaches to exploring this activity by collecting and analyzing combined eye movement and keystroke data from writers composing extended texts. ScriptLog+TimeLine is a system that is based on an existing keystroke-logging program and uses heuristic, pattern-matching methods to identify reading episodes within eye movement data. EyeWrite is an integrated editor and analysis system that permits identification of the words that the writer fixates and their location within the developing text. We demonstrate how the methods instantiated within these systems can be used to make sense of the large amount of data generated by eyetracking and keystroke logging in order to inform understanding of the cognitive processes that underlie written text production.
... and a total response index (depth index as a percentage times the number of readers). ... the... more ... and a total response index (depth index as a percentage times the number of readers). ... the importance of designing the newspaper layout so that it quickly leads the reader to the ... The subjects (experienced users of online newspaper sites) were asked to read in the manner they ...
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Papers by Kenneth Holmqvist