Gaze behavior and decision-making in simulated defensive situations for baseball fielders using a head-mounted display

• Baseball fielders viewed simulated defensive scenes using an HMD and decided where to throw. • Decision accuracy peaked with an intermediate number of visual fixations per trial. • Gaze away from the ball delayed decisions; gaze at irrelevant areas reduced accuracy. • Participants who viewed the ball longer tended to make more assertive throw decisions. • Efficient decision-making during baseball defense depends on optimal gaze behavior. Decision-making in baseball fielding requires fast and accurate assessments of multiple visual cues, including ball trajectory and runner movement. This study investigated the relationship between gaze behavior and decision-making performance during defensive plays, specifically focusing on the selection of the appropriate base to throw to. Twenty collegiate baseball fielders participated in a video-based decision-making task using a head-mounted display. Participants viewed first-person perspective videos simulating a defensive situation with one out and a runner on third base and were asked to decide whether to throw to first base or home plate. Decisions were made by pressing a button during the interval between bat–ball contact and ball capture, reflecting the real-time constraints of actual gameplay. Decision accuracy, decision time, and response bias were measured. Eye-tracking data were also collected to analyze gaze behavior such as the number of fixations and gaze transitions between areas of interest. Results revealed that decision accuracy peaked when participants made an intermediate number of fixations per trial. Gaze transition patterns showed that participants initially fixated on the ball in most trials. Trials in which participants gazed at home plate, runner, or other areas were associated with significantly longer decision times. Moreover, trials involving gaze transitions to other areas were associated with significantly lower decision accuracy. Regarding response bias, participants who spent more time viewing the ball were more likely to make assertive throw decisions by choosing home plate, whereas those who made more gaze transitions between areas of interest tended to make more conservative choices, such as selecting first base. These findings suggest that efficient gaze behavior, characterized by an optimal number of fixations and appropriate allocation of gaze, are crucial for making fast and accurate decisions during defensive plays in baseball.