UMass Amherst KIN 460 - 10-Visual attention_v3 (28 pages)

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10-Visual attention_v3



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10-Visual attention_v3

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Pages:
28
School:
University of Massachusetts Amherst
Course:
Kin 460 - Motor Control
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Overview What different types of eye movements exist What is the role of visual attention in expert performers What is visual neglect Selective visual attention Eye movements provide information about what features in the environment the person is attending to Eye movements mean shift in attention Measuring eye movements Early studies Yarbus 1967 Recordings made by Alfred Yarbus of the eye movements of a subject viewing a picture They did not expect him by I P Repin with different questions in mind Remember the clothes worn by the people Remember the positions of the people and objects in the room How long the unextected visitor had been away 3 Recording eye movements with eye trackers Recording eye movements during Trails B Test Applications Reading and multimedia learning Tobii eye tracker Consumer s behaviour Marketing Tobii eye tracker Driving Land 1998 Sports https tobii 23video com theuse of eye tracking technologyin 1 5 Different types of eye movements to bring objects of interest on the fovea Saccadic System Pursuit System Fixation System Rapidly shifts gaze from one location in visual field to another Shifts gaze so that images of a moving object remain on foveas Maintains direction of gaze so that images remain on foveas Saccadic system Typical saccadic eye movement 3 4 s with duration of 75 ms Saccadic system Small amplitude 60 eye head saccade to unexpected target Eyes move first to foveate then head in sequence Gaze direction sum eye position in socket and head position in space Eye counter rotation Vestibulo ocular reflex VOR Pursuit system Smooth pursuit movement of left eye with head stationary For each frame the target is on the eye s visual axis and therefore on fovea These are voluntary movements in response to moving stimuli cannot be elicited without movement Fixation system Gaze is held stable 3 visual angle on an object or location for 100 ms or longer Considered the minimum amount of time needed to recognize and become aware of stimuli Fixation Saccadic and Pursuit system working together Takes about 200 ms to catch up through saccade when target starts to move Overview What different types of eye movements exist How do expert performers use visual attention What is visual neglect Visual search strategies in elite and nonelite athletes Visual search paradigm Basic setup Vickers 2007 Experts can make better prediction were a ball will land based on focus on relevant cues from the body badminton cricket basketball Visual search strategies in elite and nonelite athletes Main findings Experts are more efficient and use more appropriate visual search behaviour Experts are faster in detecting and recognizing objects Experts have an enhanced ability to pickup visual cues from an opponent s postural orientation Visual search paradigm limitations Real world physical skills are rarely performed No relationship between gaze and performance outcome Limitation in natural head motion and posture Vickers 2007 Vision in action paradigm Vision in action paradigm Physical performance very similar to actual sport activity Measurable behaviour goals saved race time etc May be repeated until a certain number of successful and unsuccessful trials are accomplished Vickers 1996 The Quiet Eye Quiet eye Final fixation or tracking gaze located on a specific target or location 3 degrees visual angle and for at least 100 ms Measure of optimal perceptual motor performance Quiet eye is both earlier and longer in elite athletes and is trainable https youtu be mPZCCpmRObw Overview What different types of eye movements exist What is the role of visual attention in expert performers What is visual neglect Lesions of parietal association cortex deficits of attention Contralateral Neglect Syndrome Inability to perceive stimuli on one side of the body or environment Range from temporary loss of attention to permanent denial of one side of the body and visual field space neglect of the left side is more common Inability to process and perceive stimuli is not due to a lack of sensation Visuospatial tasks performed by individuals with contralateral neglect syndrome Neuroanatomy of neglect syndromes Part 1 Attention parietal cortex Composite of the location of underlying lesions in the right hemisphere from 8 patients Neuroanatomy of neglect syndromes Part 2 Normal brain imaging during attentional task Overview What different types of eye movements exist What is the role of visual attention in expert performers What is visual neglect Annoucements Exam 2 section 3 Changed from November 09 to November 14 Lab report 2 November 16 hard copy in class Lab exercise 9 Changed from November 16 to November 27


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