Quiet eye gaze behavior of expert, and near-expert, baseball plate umpires

The psychophysics of home plate umpire calls

We analyze the visual perception task that home plate umpires (N = 121) perform calling balls and strikes (N = 3,001,019) in baseball games, focusing on the topics of perceptual learning and bias in decision-making. In the context of perceptual learning, our results show that monitoring, training, and feedback improve skill over time. In addition, we document two other aspects of umpires' improvement that are revealing with respect to the nature of their perceptual expertise. First, we show that biases in umpires' decision-making persist even as their overall accuracy improves. This suggests that bias and accuracy are orthogonal and that reduction of bias in decision-making requires interventions aimed specifically at this goal. Second, we measure a distinct difference in the rate of skill improvement between older and younger umpires. Younger umpires improve more quickly, suggesting that the decision task umpires engage in becomes routinized over time.

The Defender's Vision-Gaze Behavior of One-on-One Defenders in Basketball

In fast-paced team sports, anticipation is one important element in defense strategies. The primary objective of this study was to examine the recommendation for action and use of defensive gaze strategies by defensive players in basketball. Four national-level expert-basketball coaches were interviewed and a field study with mobile eye-tracking devices was conducted on 16 expert and 16 novice players defending in a one-on-one situation. Differences in relative fixation times between experts and novices were elaborated for the predetermined gaze zones-head, ball, torso, and feet-as given by the expert coaches. This was done for three phases of the movement sequence: receiving, dribbling, and shooting. The results of the interviews with expert coaches indicated that the existing coaching doctrine instructs players to look at the torso of an opponent to avoid being vulnerable to fakes. Surprisingly, our findings with the players showed a discrepancy in the evaluated gaze behavior of the experts and novices. For the receiving and dribbling phase, experts mainly fixated their gaze on the head while novices focused on the ball. For the final shooting phase, both the groups mainly fixated their gaze on the ball. Fixating the gaze on the ball or head makes the player potentially vulnerable to deceptive movements, as video-based research has shown. Expert coaches also indicated that peripheral vision is of importance to defenders, contradicting the existing assumption in the literature that focusing on the task-relevant areas is key for anticipation performance.

Approximate Target Pre-Cueing Reduces Programming Quiet Eye and Movement Preparation Time: Evidence for Parameter Pre-Programming?

Purpose: We examined the effect of target pre-cues on quiet eye duration (QED). If quiet eye (QE) represents the initial and only period for the programming of movement parameters, then the precision of target pre-cues should not affect QED. In contrast, shorter QED after pre-cueing of targets implies some initial programming process to have occurred before QE. Method: Sixteen participants threw darts at targets projected onto a soft screen. We manipulated the precision of target pre-cues by highlighting an area within which the target would appear. These pre-cued areas were either the full screen (i.e., no cue), any half, quarter, or sixteenth of the screen. Participants threw eight times in each condition. Dependent measures included QED (programming and online segments), movement preparation time (MPT; from target presentation to initiation of movement), and radial error (cm). Results: Analysis revealed that programming QE was shorter when the target was pre-cued in the most precise sixteenth condition, compared to the no cue condition. Also, MPT was shorter when pre-cued in the sixteenth condition than in either the no cue or half screen conditions. Target pre-cueing conditions did not affect the other dependent variables. Conclusions: Shorter PQE following the most precise target pre-cueing implies that some pre-programming occurred before QE, perhaps through inhibition, but only when the pre-cue was specific enough to make pre-programming possible.

Visuospatial Attention and Motor Skills in Kung Fu Athletes

The present study compared the performance of a group of sixteen kung fu athletes with that of a control group of fourteen nonathletes on a speeded visuospatial task and a hand-tapping motor task. In the visuospatial task the results showed that athletes were faster than the control participants when stimuli were presented at the periphery of the visual field at a middle and high presentation speed with short interstimulus intervals. Athletes were also significantly faster than nonathlete participants when performing motor actions such as hand-tapping with their dominant hand but groups did not differ with the nondominant hand. These results support the view that athletes perform some speeded visuospatial and motor tasks faster than nonathletes under certain conditions. The findings suggest that, after several years of practice, kung fu athletes develop certain skills that allow them to perform motor speed maneuvers under time pressure conditions.