Response time, visual search strategy, and anticipatory skills in volleyball players

Abstract

This paper aimed at comparing expert and novice volleyball players in a visuomotor task using realistic stimuli. Videos of a volleyball setter performing offensive action were presented to participants, while their eye movements were recorded by a head-mounted video based eye tracker. Participants were asked to foresee the direction (forward or backward) of the setter's toss by pressing one of two keys. Key-press response time, response accuracy, and gaze behaviour were measured from the first frame showing the setter's hand-ball contact to the button pressed by the participants. Experts were faster and more accurate in predicting the direction of the setting than novices, showing accurate predictions when they used a search strategy involving fewer fixations of longer duration, as well as spending less time in fixating all display areas from which they extract critical information for the judgment. These results are consistent with the view that superior performance in experts is due to their ability to efficiently encode domain-specific information that is relevant to the task.

Figure 1

Viewpoint of the participant showing the setter's hands-ball contact. White lines delineate the interest areas. A = IA-1, coach; B = IA-2, ball trajectory; C = IA-3, setter's hands; D = IA-4, setter's trunk; and E = IA-5, setter's legs. Areas external to the contours are considered as out.

Figure 2

A lateral view of the experimental setup.

Figure 3

Correlation between gaze parameter and response time in experts' correct responses. Dots represent all participants' mean value for each correct trial. The line represents the regression coefficient (r = −.22,  P < .001) for expert groups.

Figure 4

Mean percentage of time spent by subjects viewing each fixation location for the correct and incorrect responses across groups. Black lines = experts; gray lines = novices. Asterisks show significant differences (P < .001).

Figure 5

Mean percentage of time spent by experts (a) and novices (b) viewing each location for the backward (black lines) and forward (gray lines) settings on the left chart and incorrect (black lines) and correct (gray lines) responses to the right chart. Asterisks show significant differences (P < .001).