Perceptual strategies of experts and novices in a fast ball sport

This thesis examined the perceptual strategies of expert and novice badminton players in an attempt to test notions of visual selective attention within applied, ecologically valid, sport settings. In keeping with established premises from information-processing theory it was hypothesized that the expert players would be characterized by a greater ability to extract advance information from the display (to facilitate anticipation), by the allocation of attention to the most pertinent cues available in the display (to promote search efficiency and to avoid distractions) and by the utilization of a relatively low visual search rate (as indicative of processing efficiency). In Experiment 1 the perceptual strategies of 20 elite and 35 novice badminton players were compared using a series of tasks in which the perceptual display of a badminton player was simulated using film. When the film display was manipulated using variable temporal occlusion points it was found that experts showed a consistently greater ability to predict the landing position of the shuttle from early advance cues than did novices, with the time period between 170 and 85 msec prior to racquet-shuttle contact being a critical one for the establishment of skill group differences. For both skill groups greatest improvements in prediction accuracy arose in the subsequent time period from 85 msec prior to contact to 85 msec after contact implying the criticality of cues arising in this period to the normal decision-making process. When specific spatial cues were selectively occluded from the film display the racquet and the playing side arm were found to be the principal cues upon which experts based their anticipatory prediction of shuttle direction whereas novices appeared to rely only upon racquet cues. These proficiency-related differences in cue usage were capable of explaining, in part, the differences ln anticipatory performance observed on the temporal occlusion task. Eye movements recorded during the performance of the film task (Experiment 2) were consistent with the notion of the racquet region containing the anticipatory cues of highest informational content with over 70% of all fixations occurring on that section of the display. The visual search sequence was found to normally progress from an early orientation of fixations upon gross bodily features of the opponent (such as trunk, head or lower body) to a later, more precise orientation to the region of the racquet with this apparent proximal-to-distal shift of the fixation distributions matching closely the emergent biomechanical characteristics of the stroke. Both the location and sequence of the fixations however, appeared relatively uninfluenced by the task conditions suggesting that the search patterns adopted were relatively inflexible as if pre-determined by some over-riding perceptual framework. Contrary to some earlier sport-specific investigations of the visual search process no significant differences In fixation location, duration or sequence were observed between experts and novices suggesting that the differences In anticipatory performance observed on the film task were not a consequence of differences In overt visual search characteristics. Advantages of the film task approach over the eye movement recording approach in terms of assessing actual information extraction rather than merely visual orientation were therefore apparent. Experiments 3 to 7 sought to establish the validity and reliability of the paradigm tor the assessment of individual differences in perceptual strategy used in Experiments 1 and 2. The film task was shown, using dual task methods, to provide comparable attention demands to actually playing and it was shown that concurrent eye movement recording could take place without interference with the subject's response to the film task. Prediction error measures derived from the film task were found to have high reliability with identical conclusions being reached regarding individual subject's perceptual strategies on each occasion the test was administered. Visual search parameters appeared somewhat less reliable with the same anticipatory performance being apparently possible through the use of different search rates, although fixation location and order characteristics remained consistent over time. When the ski II group distinction was reduced and an alternative form of error analysis was adopted the characteristic earlier extraction of information and greater utilization of arm cues by experts again emerged, suggesting that the proficiency-related differences observed in Experiment 1 were robust ones