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O'Brien-Smith J, Smith MR, Vansteenkiste P, Fransen J, Zeuwts L, Bennett KJM, Lenoir M. Understanding the role of gaze behaviour and coaching experience in the assessment of youth soccer teams. SCI MED FOOTBALL 2024:1-9. [PMID: 38512014 DOI: 10.1080/24733938.2024.2325135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 02/22/2024] [Indexed: 03/22/2024]
Abstract
This study aimed to explore the perceptual-cognitive characteristics of coaches as they assessed team performance in youth soccer. The primary focus was to investigate the alignment between coaches' subjective analyses of team behaviour and objective analyses, while also examining the relationship between coaches' gaze behaviour and their levels of coaching experience, particularly considering the potential differences that may exist among coaches with varying levels of experience. Sixty-five male and female adults with various soccer coaching experience (experienced, novice, other team sport experience, and non-team sport experience) watched five 4-minute videos and assessed team behaviour. These subjective evaluations were compared to objective data obtained from video analysis and GPS, which included measures of completed skills, spatiotemporal characteristics, and passing networks. The participants' fixation duration and frequency were measured for each video clip, and the area around the ball specifically. The study found no significant differences between groups regarding the number of times participants' subjective analysis aligned with the objective data (p = 0.059, ɳ2 = 0.07). However, coaches with soccer coaching experience demonstrated a higher fixation frequency and more revisits to the ball area when compared to participants without soccer experience (p = <.001, ɳ2 = 0.09). The current study offers a unique approach to uncovering soccer coaching expertise by combining objective and subjective evaluations of team performance. In summary, the study reveals that coaching experience did not impact how often coaches subjective analyses matched objective data. However, soccer coaches had distinctive gaze behaviour patterns where they revisited the area around the ball more often.
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Affiliation(s)
- Jade O'Brien-Smith
- School of Environmental and Life Sciences, Faculty of Science, University of Newcastle, Ourimbah, Australia
- Faculty of Medicine and Health Sciences, Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
- School of Health Sciences, Faculty of Medicine and Health, University of New South Wales, Sydney, Australia
| | - Mitchell R Smith
- School of Environmental and Life Sciences, Faculty of Science, University of Newcastle, Ourimbah, Australia
| | - Pieter Vansteenkiste
- Faculty of Medicine and Health Sciences, Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | - Job Fransen
- School of Allied Health, Exercise and Sports Sciences, Charles Sturt University, Port Macquarie, Australia
| | - Linus Zeuwts
- Faculty of Medicine and Health Sciences, Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | - Kyle J M Bennett
- Physical Activity, Sport and Exercise Research Theme, Faculty of Health, Southern Cross University, Coffs Harbour, Australia
| | - Matthieu Lenoir
- Faculty of Medicine and Health Sciences, Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
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Starke SD, May SA. Expert visual assessment strategies for equine lameness examinations in a straight line and circle: A mixed methods study using eye tracking. Vet Rec 2022; 191:e1684. [PMID: 35716395 DOI: 10.1002/vetr.1684] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 02/14/2022] [Accepted: 03/30/2022] [Indexed: 11/07/2022]
Abstract
BACKGROUND A large number of lameness indicators have been suggested for the visual equine lameness assessment. However, it remains unknown which of these are commonly used by experts. METHODS Twenty-four expert lameness assessors from 10 leading UK institutions viewed 28 video clips of sound and mildly lame horses (median score 2/10). Horses were shown at trot in a straight line (rear and front view) and circle (side view, left and right rein). Eye tracking data were collected at 60 Hz while participants evaluated each clip. A questionnaire captured contextual information. RESULTS During assessment on the straight line, participants consistently looked mostly at the head and pelvis. On the circle, many participants consistently looked at the head, yet the subsequent choice, weighting and order of examined body regions was unsystematic between and within participants, and there was a bias towards prolonged assessment of the horse's front region. Questionnaires revealed different descriptions of lameness indicators for the same body region and different approaches to decision making under uncertainty. CONCLUSION In contrast to reasonably high similarity on the straight line, expert veterinarians have not developed a consistent assessment approach when evaluating horses on the circle. The reliability of various lameness indicators on the circle requires a stronger evidence base for a more systematic, repeatable approach.
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Affiliation(s)
- Sandra D Starke
- Clinical Science and Services, Royal Veterinary College, Hatfield, Hertfordshire, UK
| | - Stephen A May
- Clinical Science and Services, Royal Veterinary College, Hatfield, Hertfordshire, UK
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Waters A, Panchuk D, Phillips E, Dawson A. Experiential Knowledge Affects the Visual Search Behaviors of Sprint Coaches and Sport Biomechanists. Front Sports Act Living 2020; 2:95. [PMID: 33345086 PMCID: PMC7739663 DOI: 10.3389/fspor.2020.00095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Accepted: 06/18/2020] [Indexed: 11/20/2022] Open
Abstract
It is common for applied sport biomechanists and high-performance coaches to work closely together. A feature of this relationship is that both bring unique experiences and knowledge to the common goal of improving an athlete's performance. For sprint running, coaches and biomechanists place importance on different aspects of technique. The purpose of this paper was to determine if these differences in experiential knowledge impact coaches and biomechanists visual perception of sprinting technique. Sport biomechanists (n = 12) and, expert (n = 11) and developing (n = 11) coaches watched video of athletes sprinting at two different speeds while wearing eye tracking glasses and, retrospectively, reported on the technique features observed. Mixed methods ANOVAs were used to determine visual search strategies and efficiency and used to indicate the relationship between visual search and verbal commentary data. The speed of video playback was the main determinant of visual search behavior, significantly impacting the visual search rate and relative fixation duration at a number of areas of interest. The use of a visual pivot indicated all participants' visual search strategies were efficiency driven. Overall, the verbal commentary did not completely align with the eye tracking data and there were varying degrees of agreement with the identified technique related areas of interest for coaches and biomechanists. However, differences in visual search strategy and verbal commentary suggest that experiential knowledge impacts participants' observation and perception of sprinting technique.
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Affiliation(s)
- Amy Waters
- Institute of Health and Sport, Victoria University, Melbourne, VIC, Australia.,Movement Science, Australian Institute of Sport, Canberra, ACT, Australia
| | - Derek Panchuk
- Institute of Health and Sport, Victoria University, Melbourne, VIC, Australia
| | - Elissa Phillips
- Movement Science, Australian Institute of Sport, Canberra, ACT, Australia
| | - Andrew Dawson
- Institute of Health and Sport, Victoria University, Melbourne, VIC, Australia
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Mitchell J, Maratos FA, Giles D, Taylor N, Butterworth A, Sheffield D. The Visual Search Strategies Underpinning Effective Observational Analysis in the Coaching of Climbing Movement. Front Psychol 2020; 11:1025. [PMID: 32670131 PMCID: PMC7326104 DOI: 10.3389/fpsyg.2020.01025] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/24/2020] [Indexed: 12/30/2022] Open
Abstract
Despite the importance of effective observational analysis in coaching the technical aspects of climbing performance, limited research informs this aspect of climbing coach education. Thus, the purpose of the present research was to explore the feasibility and the utility of a novel methodology, combining eye tracking technology and cued retrospective think-aloud (RTA), to capture the cognitive–perceptual mechanisms that underpin the visual search behaviors of climbing coaches. An analysis of gaze data revealed that expert climbing coaches demonstrate fewer fixations of greater duration and fixate on distinctly different areas of the visual display than their novice counterparts. Cued RTA further demonstrated differences in the cognitive–perceptual mechanisms underpinning these visual search strategies, with expert coaches being more cognizant of their visual search strategy. To expand, the gaze behavior of expert climbing coaches was underpinned by hierarchical and complex knowledge structures relating to the principles of climbing movement. This enabled the expert coaches to actively focus on the most relevant aspects of a climber’s performance for analysis. The findings demonstrate the utility of combining eye tracking and cued RTA interviewing as a new, efficient methodology of capturing the cognitive–perceptual processes of climbing coaches to inform coaching education/strategies.
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Affiliation(s)
- James Mitchell
- Human Sciences Research Centre, College of Life and Natural Sciences, University of Derby, Derby, United Kingdom
| | - Frances A Maratos
- Human Sciences Research Centre, College of Life and Natural Sciences, University of Derby, Derby, United Kingdom
| | - Dave Giles
- Human Sciences Research Centre, College of Life and Natural Sciences, University of Derby, Derby, United Kingdom.,Lattice Training Ltd., Chesterfield, United Kingdom
| | - Nicola Taylor
- Human Sciences Research Centre, College of Life and Natural Sciences, University of Derby, Derby, United Kingdom
| | - Andrew Butterworth
- Human Sciences Research Centre, College of Life and Natural Sciences, University of Derby, Derby, United Kingdom
| | - David Sheffield
- Human Sciences Research Centre, College of Life and Natural Sciences, University of Derby, Derby, United Kingdom
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Fewer fixations of longer duration? Expert gaze behavior revisited. GERMAN JOURNAL OF EXERCISE AND SPORT RESEARCH 2019. [DOI: 10.1007/s12662-019-00616-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Mack M. Exploring Cognitive and Perceptual Judgment Processes in Gymnastics Using Essential Kinematics Information. Adv Cogn Psychol 2019; 16:34-44. [PMID: 32547666 PMCID: PMC7287510 DOI: 10.5709/acp-0282-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The aim of the current study was to transfer the method of using isolated kinematics information combined with the examination of perceptual-cognitive processes to gymnastics judging and thereby investigating the informational underpinnings of skilled perception and judgment. More specifically, a combination of process-tracing methods that include both the gaze pattern (via eye tracking) and the performance judgment (via ratings on a six-point Likert scale) of participants with different gymnastics expertise (visual experts, n = 14, motor experts, n = 17, novices, n = 18) was employed for gymnastics performances of a floor routine (round off, back handspring, back layout somersault), which were shown as videos in original or in stick-figure format. Gaze pattern was analyzed for the whole floor routine as well as for the particular temporal-spatial windows of the three motor skills. Differences between visual experts, motor experts, and novices could be found concerning the judgment score, ηp2 = .242, and the judgment accuracy, ηp2 = .196, but not the gaze pattern. The significant interaction effects between skill and format for the gaze pattern show the importance of the last skill in the judgment processes. Further research should investigate the influence of judgment instruction on the gaze pattern as well as the importance of the last skill for the judgment score.
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Affiliation(s)
- Melanie Mack
- Faculty of Sport Science, Leipzig University, Leipzig, Germany
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Roach VA, Fraser GM, Kryklywy JH, Mitchell DGV, Wilson TD. Guiding Low Spatial Ability Individuals through Visual Cueing: The Dual Importance of Where and When to Look. ANATOMICAL SCIENCES EDUCATION 2019; 12:32-42. [PMID: 29603656 DOI: 10.1002/ase.1783] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 03/01/2018] [Accepted: 03/03/2018] [Indexed: 05/28/2023]
Abstract
Research suggests that spatial ability may predict success in complex disciplines including anatomy, where mastery requires a firm understanding of the intricate relationships occurring along the course of veins, arteries, and nerves, as they traverse through and around bones, muscles, and organs. Debate exists on the malleability of spatial ability, and some suggest that spatial ability can be enhanced through training. It is hypothesized that spatial ability can be trained in low-performing individuals through visual guidance. To address this, training was completed through a visual guidance protocol. This protocol was based on eye-movement patterns of high-performing individuals, collected via eye-tracking as they completed an Electronic Mental Rotations Test (EMRT). The effects of guidance were evaluated using 33 individuals with low mental rotation ability, in a counterbalanced crossover design. Individuals were placed in one of two treatment groups (late or early guidance) and completed both a guided, and an unguided EMRT. A third group (no guidance/control) completed two unguided EMRTs. All groups demonstrated an increase in EMRT scores on their second test (P < 0.001); however, an interaction was observed between treatment and test iteration (P = 0.024). The effect of guidance on scores was contingent on when the guidance was applied. When guidance was applied early, scores were significantly greater than expected (P = 0.028). These findings suggest that by guiding individuals with low mental rotation ability "where" to look early in training, better search approaches may be adopted, yielding improvements in spatial reasoning scores. It is proposed that visual guidance may be applied in spatial fields, such as STEMM (science, technology, engineering, mathematics and medicine), surgery, and anatomy to improve student's interpretation of visual content. Anat Sci Educ. © 2018 American Association of Anatomists.
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Affiliation(s)
- Victoria A Roach
- Department of Biomedical Sciences, William Beaumont School of Medicine, Oakland University, Rochester, Michigan
| | - Graham M Fraser
- Cardiovascular Research Group, Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | - James H Kryklywy
- Department of Psychology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Derek G V Mitchell
- Department of Psychiatry, Schulich School of Medicine and Dentistry, Brain and Mind Institute, London, Ontario, Canada
- Department of Psychology, The University of Western Ontario, London, Ontario, Canada
- Department of Anatomy and Cell Biology, Corps for Research of Instructional and Perceptual Technologies, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Timothy D Wilson
- Department of Anatomy and Cell Biology, Corps for Research of Instructional and Perceptual Technologies, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
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Exploring Visual Patterns and Judgments Predicated on Role Specificity: Case Studies of Expertise in Gymnastics. CURRENT PSYCHOLOGY 2018. [DOI: 10.1007/s12144-017-9572-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Haering D, Huchez A, Barbier F, Holvoët P, Begon M. Identification of the contribution of contact and aerial biomechanical parameters in acrobatic performance. PLoS One 2017; 12:e0172083. [PMID: 28422954 PMCID: PMC5396868 DOI: 10.1371/journal.pone.0172083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 01/31/2017] [Indexed: 11/18/2022] Open
Abstract
INTRODUCTION Teaching acrobatic skills with a minimal amount of repetition is a major challenge for coaches. Biomechanical, statistical or computer simulation tools can help them identify the most determinant factors of performance. Release parameters, change in moment of inertia and segmental momentum transfers were identified in the prediction of acrobatics success. The purpose of the present study was to evaluate the relative contribution of these parameters in performance throughout expertise or optimisation based improvements. The counter movement forward in flight (CMFIF) was chosen for its intrinsic dichotomy between the accessibility of its attempt and complexity of its mastery. METHODS Three repetitions of the CMFIF performed by eight novice and eight advanced female gymnasts were recorded using a motion capture system. Optimal aerial techniques that maximise rotation potential at regrasp were also computed. A 14-segment-multibody-model defined through the Rigid Body Dynamics Library was used to compute recorded and optimal kinematics, and biomechanical parameters. A stepwise multiple linear regression was used to determine the relative contribution of these parameters in novice recorded, novice optimised, advanced recorded and advanced optimised trials. Finally, fixed effects of expertise and optimisation were tested through a mixed-effects analysis. RESULTS AND DISCUSSION Variation in release state only contributed to performances in novice recorded trials. Moment of inertia contribution to performance increased from novice recorded, to novice optimised, advanced recorded, and advanced optimised trials. Contribution to performance of momentum transfer to the trunk during the flight prevailed in all recorded trials. Although optimisation decreased transfer contribution, momentum transfer to the arms appeared. CONCLUSION Findings suggest that novices should be coached on both contact and aerial technique. Inversely, mainly improved aerial technique helped advanced gymnasts increase their performance. For both, reduction of the moment of inertia should be focused on. The method proposed in this article could be generalized to any aerial skill learning investigation.
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Affiliation(s)
- Diane Haering
- Institut National de Recherche en Informatique et Automatique Rennes - Bretagne Atlantique, Campus de Beaulieu, Rennes, France
- Université de Montréal, Department of Kinesiology, Laboratory of Simulation & Movement Modeling, Laval, Québec, Canada
| | - Aurore Huchez
- Université de Valenciennes et du Hainaut Cambrésis, Laboratoire d’Automatique et Mécanique Industrielles et Humaines, Le Mont Houy, Valenciennes, France
| | - Franck Barbier
- Université de Valenciennes et du Hainaut Cambrésis, Laboratoire d’Automatique et Mécanique Industrielles et Humaines, Le Mont Houy, Valenciennes, France
| | - Patrice Holvoët
- Université de Lille 2, Faculté des Sciences du Sport et de l’Education Physique, Ronchin, France
| | - Mickaël Begon
- Université de Montréal, Department of Kinesiology, Laboratory of Simulation & Movement Modeling, Laval, Québec, Canada
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Reproducibility of a battery of commonly used clinical tests to evaluate lumbopelvic motor control. Phys Ther Sport 2015; 16:331-9. [DOI: 10.1016/j.ptsp.2015.02.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 02/06/2015] [Accepted: 02/27/2015] [Indexed: 11/18/2022]
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FLESSAS KONSTANTINOS, MYLONAS DIMITRIS, PANAGIOTAROPOULOU GEORGIA, TSOPANI DESPINA, KORDA ALEXANDREA, SIETTOS CONSTANTINOS, DI CAGNO ALESSANDRA, EVDOKIMIDIS IOANNIS, SMYRNIS NIKOLAOS. Judging the Judges’ Performance in Rhythmic Gymnastics. Med Sci Sports Exerc 2015; 47:640-8. [DOI: 10.1249/mss.0000000000000425] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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12
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Chen JD, Falkmer T, Parsons R, Buzzard J, Ciccarelli M. Impact of experience when using the Rapid Upper Limb Assessment to assess postural risk in children using information and communication technologies. APPLIED ERGONOMICS 2014; 45:398-405. [PMID: 23735750 DOI: 10.1016/j.apergo.2013.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 03/19/2013] [Accepted: 05/06/2013] [Indexed: 06/02/2023]
Abstract
The Rapid Upper Limb Assessment (RULA) is an observation-based screening tool that has been used to assess postural risks of children in school settings. Studies using eye-tracking technology suggest that visual search strategies are influenced by experience in the task performed. This study investigated if experience in postural risk assessments contributed to differences in outcome scores on the RULA and the visual search strategies utilized. While wearing an eye-tracker, 16 student occupational therapists and 16 experienced occupational therapists used the RULA to assess 11 video scenarios of a child using different mobile information and communication technologies (ICT) in the home environment. No significant differences in RULA outcome scores, and no conclusive differences in visual search strategies between groups were found. RULA can be used as a screening tool for postural risks following a short training session regardless of the assessor's experience in postural risk assessments.
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Affiliation(s)
- Janice D Chen
- School of Occupational Therapy and Social Work, Curtin University, Perth 6845, Australia
| | - Torbjörn Falkmer
- School of Occupational Therapy and Social Work, Curtin University, Perth 6845, Australia; Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Linköping University & Pain and Rehabilitation Centre, UHL, County Council, Linköping SE 581 85, Sweden; School of Health Sciences, Jönköping University, Sweden; School of Occupational Therapy, La Trobe University, Melbourne 3083, Australia
| | - Richard Parsons
- School of Occupational Therapy and Social Work, Curtin University, Perth 6845, Australia; Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Linköping University & Pain and Rehabilitation Centre, UHL, County Council, Linköping SE 581 85, Sweden
| | | | - Marina Ciccarelli
- School of Occupational Therapy and Social Work, Curtin University, Perth 6845, Australia; Rehabilitation Medicine, Department of Medicine and Health Sciences (IMH), Faculty of Health Sciences, Linköping University & Pain and Rehabilitation Centre, UHL, County Council, Linköping SE 581 85, Sweden.
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Thelwell RC, Page JL, Lush A, Greenlees IA, Manley AJ. Can reputation biases influence the outcome and process of making competence judgments of a coach? Scand J Med Sci Sports 2012; 23:e65-73. [DOI: 10.1111/sms.12000] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/13/2012] [Indexed: 11/30/2022]
Affiliation(s)
| | - J. L. Page
- University of Portsmouth; Portsmouth; UK
| | - A. Lush
- University of Portsmouth; Portsmouth; UK
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Gegenfurtner A, Lehtinen E, Säljö R. Expertise Differences in the Comprehension of Visualizations: a Meta-Analysis of Eye-Tracking Research in Professional Domains. EDUCATIONAL PSYCHOLOGY REVIEW 2011. [DOI: 10.1007/s10648-011-9174-7] [Citation(s) in RCA: 165] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Brockmole JR, Hambrick DZ, Windisch DJ, Henderson JM. The role of meaning in contextual cueing: evidence from chess expertise. Q J Exp Psychol (Hove) 2009; 61:1886-96. [PMID: 18609364 DOI: 10.1080/17470210701781155] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
In contextual cueing, the position of a search target is learned over repeated exposures to a visual display. The strength of this effect varies across stimulus types. For example, real-world scene contexts give rise to larger search benefits than contexts composed of letters or shapes. We investigated whether such differences in learning can be at least partially explained by the degree of semantic meaning associated with a context independently of the nature of the visual information available (which also varies across stimulus types). Chess boards served as the learning context as their meaningfulness depends on the observer's knowledge of the game. In Experiment 1, boards depicted actual game play, and search benefits for repeated boards were 4 times greater for experts than for novices. In Experiment 2, search benefits among experts were halved when less meaningful randomly generated boards were used. Thus, stimulus meaningfulness independently contributes to learning context-target associations.
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Itti L. Automatic foveation for video compression using a neurobiological model of visual attention. IEEE TRANSACTIONS ON IMAGE PROCESSING : A PUBLICATION OF THE IEEE SIGNAL PROCESSING SOCIETY 2004; 13:1304-1318. [PMID: 15462141 DOI: 10.1109/tip.2004.834657] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We evaluate the applicability of a biologically-motivated algorithm to select visually-salient regions of interest in video streams for multiply-foveated video compression. Regions are selected based on a nonlinear integration of low-level visual cues, mimicking processing in primate occipital, and posterior parietal cortex. A dynamic foveation filter then blurs every frame, increasingly with distance from salient locations. Sixty-three variants of the algorithm (varying number and shape of virtual foveas, maximum blur, and saliency competition) are evaluated against an outdoor video scene, using MPEG-1 and constant-quality MPEG-4 (DivX) encoding. Additional compression radios of 1.1 to 8.5 are achieved by foveation. Two variants of the algorithm are validated against eye fixations recorded from four to six human observers on a heterogeneous collection of 50 video clips (over 45 000 frames in total). Significantly higher overlap than expected by chance is found between human and algorithmic foveations. With both variants, foveated clips are, on average, approximately half the size of unfoveated clips, for both MPEG-1 and MPEG-4. These results suggest a general-purpose usefulness of the algorithm in improving compression ratios of unconstrained video.
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Affiliation(s)
- Laurent Itti
- Departments of Computer Science, Psychology and Neuroscience Graduate Program, University of Southern California, Los Angeles, CA 90089-2520, USA.
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