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Title:Visual search strategy and interception accuracy
Author(s):Lim, Jong
Director of Research:Carlton, Les G.
Doctoral Committee Chair(s):Carlton, Les G.
Doctoral Committee Member(s):Petruzzello, Steven J.; Morrow, Daniel G.; Sosnoff, Jacob J.
Department / Program:Kinesiology & Community Health
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Eye movement
Moving target
Abstract:Interceptive projectile aiming to a moving target such as passing in American football requires a coordinated movement sequence based on accurately perceived and/or predicted object motion characteristics. I addressed the questions of how visual search strategy and interception accuracy are influenced by constraints. Two experiments, manipulating spatial and temporal target motion configuration, assessed the role of constraints in interceptive aiming in interception accuracy and gaze control strategy. In Experiment 1, there was an influence of constraints imposed on target speed and interception location on gaze control strategy as well as spatial and temporal accuracy of performance. With changes in target speed, the interdependent relationship between spatial and temporal accuracy was observed. Constraining the point of interception resulted in increased spatial and timing error in hitting the moving target but spatial variability of the interception point in laboratory space was independent of the interception point constraint. The greater tendency to gaze at the intended interception point, induced by the presence of a specified interception point, indicates that direct tracking of the target may not be optimal in tasks where the movement execution time and flight time are relatively long. In Experiment 2, gaze control and interception accuracy was examined under known and repeated target speed presentation and compared to unknown and random presentation conditions. Target speed and spatial path were also varied from highly predictable to less predictable patterns. Spatial and temporal accuracy were inversely related to each other. Variation in aimed location in laboratory space was significantly influenced by target motion predictability, but not influenced by target speed. Point of gaze data also indicated that participants tended to track the moving target more, rather than look at the anticipated interception location, as target motion became less predictable. Overall, the task constraints employed in present experiments showed a significant association with point of gaze distribution. However, the results also highlight the importance of considering the task context with the functional role of the eye. As a result, a task specific interception strategy may be required, so that the eye, head, and effector maybe coordinated to both optimize perceptual resources as well as facilitate accurate object interception.
Issue Date:2013-05-24
Rights Information:Copyright 2013 Jongil Lim
Date Available in IDEALS:2013-05-24
Date Deposited:2013-05

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