Title: Investigating Visual and Motor Influences on Action Prediction of a Volleyball Set Action
Thesis Supervisor: Dr. Nicola Hodges
Committee members: Dr. Romeo Chua, Dr. Christian Vater
Defence Chair: Dr. Hyosub Kim
Abstract:
In high-performance sports, anticipating an opponent’s actions provides a significant advantage for fast and accurate responding. One proposed mechanism for this anticipatory process is internal action simulation, which enables athletes to predict actions by accessing motor representations. Previous research suggests that motor experience enhances anticipation by facilitating this simulation process (Aglioti et al., 2008). However, even in the absence of direct motor experience, individuals may still develop anticipatory skills through visual attunement to key kinematic cues, using the visual system as a static matching process in proxy of a dynamic simulation which functions with the motor experience (Mulligan et al., 2016b; Chen et al., 2017; Tomeo et al., 2013).
This study investigated how visual and motor experience contribute to action prediction in a volleyball set by comparing expert and intermediate volleyball players (N = 49). Three positional groups were tested: Setters (high motor experience setting, n = 15), Blockers (high visual experience responding to setting actions, n = 17), and Outside-hitters (lower experience responding to sets, n = 15). Using a temporal occlusion paradigm, participants viewed setting actions from either a first-person, setter perspective or third-person, blocker perspective, making predictions about set direction at varying occlusion points.
Results revealed that outside hitters were significantly less accurate than expert setters and blockers, but overall, expert setters and blockers did not differ. Skill-based differences emerged at -60ms before ball contact, with expert setters and blockers (~65-70% accuracy) outperforming their intermediate counterparts (~45-50%). However, prediction accuracy differences between skill groups were reduced at ball contact. This suggests that experts could extract and utilize early kinematic cues, whereas intermediates may have relied more on ball-flight cues that were unavailable at earlier occlusion points. Surprisingly, perspective did not significantly influence accuracy, contrary to predictions that setters and blockers would perform better from their dominant perspective. These data suggest that motor and visual experiences both contribute-somewhat equally to action prediction, challenging the idea that motor experience facilitates prediction accuracy. Although we did not have evidence for differences in mechanisms across the setters and blockers, recommendations for future work involve more mechanistic exploration, including perhaps measures of eye-tracking.