Kenneth Holmqvist | Lund University (original) (raw)

Papers by Kenneth Holmqvist

Current Trends in Eye Tracking Research, 2013

Nordic Journal of Linguistics, 1996

In our article, we start by posing the question why some adjectival stems can end both in -ful an... more In our article, we start by posing the question why some adjectival stems can end both in -ful and -less, while others take only one of the endings. Together these items make up around 1% of the entries in a good dictionary. It soon becomes clear that we need to use several basic concepts from cognitive linguistics to an swer our question: boundedness, mass vs. individual, part-whole relations and container metaphors. By this we can divide the -ful and -less items into a number of subgroups with different semantics. The most important aspect of their semantics, however, is that both -ful andless express deviations from our expectations of how the normal world is structured. In other words; they represent the world by negating it.

Journal of Electronic Imaging, 2007

ACM Transactions on Multimedia Computing, Communications, and Applications, 2010

Offline foveation is a technique to improve the compression efficiency of digitized video. The ge... more Offline foveation is a technique to improve the compression efficiency of digitized video. The general idea behind offline foveation is to blur video regions where no or a small number of previewers look without decreasing the subjective quality for later viewers. It relies on the fact that peripheral vision is reduced compared to central vision, and the observation that during free-viewing humans' gaze positions generally coincide when watching video. In this article, we conduct two experiments to assess how offline foveation affects viewing behavior and subjective quality. In the first experiment, 15 subjects free-viewed six video clips before and after offline foveation whereas in the second experiment we had 17 subjects assessing the quality of these videos after one, two, and three consecutive viewings. Eye movements were measured during the experiments. Results showed that, although offline foveation prior to encoding with H.264 yielded data reductions up to 52% (20% average) on the tested videos, it had little or no effect on where people looked, their intersubject dispersion, fixation duration, saccade amplitude, or the experienced quality during first-time viewing. However, seeing the videos more than once increased the intersubject dispersion and decreased the subjective quality. In view of these results, we discuss the usage of offline foveated video in practical applications.

Pedagogische Studien, 2010

Jarodzka, H., Balslev, T., Holmqvist, K., Nyström, M., Scheiter, K., Gerjets, P., &amp; E... more Jarodzka, H., Balslev, T., Holmqvist, K., Nyström, M., Scheiter, K., Gerjets, P., &amp; 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.

Guidance of eye-movements in image viewing is believed to be controlled by stimulus driven factor... more Guidance of eye-movements in image viewing is believed to be controlled by stimulus driven factors as well as viewer dependent higher level factors such as task and memory. It is currently debated what proportions these factors contribute to gaze guidance, and also how they vary over time after image onset. Overall, the unanimity regarding these issues is surprisingly low and there are results supporting both types of factors as being dominant in eye-movement control under certain conditions. We investigate how low, and high level factors influence eye guidance by manipulating contrast statistics on images from three different semantic categories and measure how this affects fixation selection. Our results show that the degree to which contrast manipulations affect fixation selection heavily depends on an image's semantic content, and how this content is distributed over the image. Over the three image categories, we found no systematic differences between contrast and edge density at fixated location compared to control locations, neither during the initial fixation nor over the whole time course of viewing. These results suggest that cognitive factors easily can override low-level factors in fixation selection, even when the viewing task is neutral.

Behavior Research Methods, 2010

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.

European Journal of Paediatric Neurology

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.

Cognitive Science, 2006

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.

Behavior Research Methods, 2009

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 ...

Applied Cognitive Psychology, 2009

In a naturalistic newspaper reading study, two pairs of information graphics have been designed t... more In a naturalistic newspaper reading study, two pairs of information graphics have been designed to study the effects of (a) the spatial contiguity principle and (b) the dual scripting principle by means of eye tracking measurements. Our data clearly show that different spatial layouts have a significant effect on readers' eye movement behaviour. An integrated format with spatial contiguity between text and illustrations facilitates integration. Reading of information graphics is moreover significantly enhanced by a serial format, resulting from dual attentional guidance. The dual scripting principle is associated with a bottom-up guidance through the spatial layout of the presentation, suggesting a specific reading path, and with a top-down guidance through the conceptual pre-processing of the contents, facilitating information processing and semantic integration of the material. The integrated and serial formats not only attract readers' initial attention but also sustain the readers' interest, thereby promoting a longer and deeper processing of the complex material. The results are an important contribution to the study of the cognitive processes involved in text-picture integration and offer relevant insights about attentional guidance in printed media, computer-based instructional materials and textbook design. Copyright © 2008 John Wiley & Sons, Ltd.

In direct face-to-face communication, we use a variety of different means of expression with diff... more In direct face-to-face communication, we use a variety of different means of expression with different degrees of consciousness and intentionality . Communication is multimodal and embodied. In parallel to verbally formulating our conscious message, we also convey information with our voice, mimics, gaze, gestures and body posture. The aim of this paper is to analyse the use of spontaneous gestures accompanying spoken discourse on 'others'. The first example shows that the ethnic references can be made in the gestural channel, keeping the spoken channel free from explicit ethnic reference. In the second example, a variety of gestures illustrate and emphasise the events referred to in the spoken discourse.

Brain and Language, 2009

In reading, both foveal (currently fixated word) and parafoveal (information outside the current ... more In reading, both foveal (currently fixated word) and parafoveal (information outside the current fixation) information are important. Having only the fixated word available slows reading, but having the fixated word and the next word (or the beginning letters of the next word) available is almost as good as having the whole line .