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Ahlström, Christer, et al.
(författare)
Fit-for-duty test for estimation of drivers sleepiness level: Eye movements improve the sleep/wake predictor
2013
Ingår i: Transportation Research Part C. - : Elsevier. - 0968-090X .- 1879-2359. ; 26, s. 20-32
Tidskriftsartikel (refereegranskat) abstract
Driver sleepiness contributes to a considerable proportion of road accidents, and a fit-for-duty test able to measure a drivers sleepiness level might improve traffic safety. The aim of this study was to develop a fit-for-duty test based on eye movement measurements and on the sleep/wake predictor model (SWP, which predicts the sleepiness level) and evaluate the ability to predict severe sleepiness during real road driving. Twenty-four drivers participated in an experimental study which took place partly in the laboratory, where the fit-for-duty data were acquired, and partly on the road, where the drivers sleepiness was assessed. A series of four measurements were conducted over a 24-h period during different stages of sleepiness. Two separate analyses were performed; a variance analysis and a feature selection followed by classification analysis. In the first analysis it was found that the SWP and several eye movement features involving anti-saccades, pro-saccades, smooth pursuit, pupillometry and fixation stability varied significantly with different stages of sleep deprivation. In the second analysis, a feature set was determined based on floating forward selection. The correlation coefficient between a linear combination of the acquired features and subjective sleepiness (Karolinska sleepiness scale, KSS) was found to be R = 0.73 and the correct classification rate of drivers who reached high levels of sleepiness (KSS andgt;= 8) in the subsequent driving session was 82.4% (sensitivity = 80.0%, specificity = 84.2% and AUC = 0.86). Future improvements of a fit-for-duty test should focus on how to account for individual differences and situational/contextual factors in the test, and whether it is possible to maintain high sensitive/specificity with a shorter test that can be used in a real-life environment, e.g. on professional drivers.
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Andersson, Richard, et al.
(författare)
Sampling frequency and eye-tracking measures : how speed affects durations, latencies, and more
2010
Ingår i: Journal of Eye Movement Research. - : University of Bern. - 1995-8692. ; 3:3:6, s. 1-12
Tidskriftsartikel (refereegranskat) abstract
We use simulations to investigate the effect of sampling frequency on common dependent variables in eye-tracking. We identify two large groups of measures that behave differently, but consistently. The effect of sampling frequency on these two groups of measures are explored and simulations are performed to estimate how much data are required to overcome the uncertainty of a limited sampling frequency. Both simulated and real data are used to estimate the temporal uncertainty of data produced by low sampling frequencies. The aim is to provide easy-to-use heuristics for researchers using eye-tracking. For example, we show how to compensate the uncertainty of a low sampling frequency with more data and post-experiment adjustments of measures. These findings have implications primarily for researchers using naturalistic setups where sampling frequencies typically are low.
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Bianchi, Ivana, et al.
(författare)
Identification of opposites and intermediates by eye and by hand
2017
Ingår i: Acta Psychologica. - 1873-6297. ; 180, s. 175-189
Tidskriftsartikel (refereegranskat) abstract
In this eye-tracking and drawing study, we investigate the perceptual grounding of different types of spatial dimensions such as DENSE–SPARSE and TOP–BOTTOM, focusing both on the participants’ experiences of the opposite regions, e.g., O1: DENSE; O2: SPARSE, and the region that is experienced as intermediate, e.g., INT: NEITHER DENSE NOR SPARSE. Six spatial dimensions expected to have three different perceptual structures in terms of the point and range nature of O1, INT and O2 were analysed. Presented with images, the participants were instructed to identify each region (O1, INT, O2), first by looking at the region, and then circumscribing it using the computer mouse. We measured the eye movements, identification times and various characteristics of the drawings such as the relative size of the three regions, overlaps and gaps. Three main results emerged. Firstly, generally speaking, intermediate regions were not different from the poles on any of the indicators: overall identification times, number of fixations, and locations. Some differences emerged with regard to the duration of fixations for point INTs and the number of fixations for range INTs between two range poles (O1, O2). Secondly, the analyses of the fixation locations showed that the poles support the identification of the intermediate region as much as the intermediate region supports the identification of the poles. Finally, the relative size of the three areas selected in the marking task were consistent with the classification of the regions as points or ranges. The analyses of the gaps and the overlaps between the three areas showed that the intermediate is neither O1 nor O2, but an entity in its own right.
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Brante, Eva Wennås, 1961, et al.
(författare)
Exploring the Impact of Contrasting Cases in Text and Picture Processing
2013
Ingår i: Journal of Visual Literacy. - : Informa UK Limited. - 1051-144X .- 2379-6529. ; 32:2, s. 15-38
Tidskriftsartikel (refereegranskat) abstract
Abstract Multimodal learning materials are frequently met in education assuming enhanced learning outcomes. This study examined whether contrasts in such materials are likely to support reading comprehension for all readers. Young adults (n=46) met either text-only or text+picture material. Participants (19 with low phonological awareness [PA] and 27 controls with high PA) thereafter answered open interview questions to check for reading comprehension. Learning materials were designed to focus readers on aspects critical to understanding the content by the use of contrasts; eye-tracking was used as method. Well-known pictures aided information recall, but contrasts described in the text were most effective for learning.
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