This study investigated whether soccer penalty-takers can exploit predictive information from the goalkeeper’s actions. Eight low- and seven high-skilled participants kicked balls in a penalty task with the goalkeeper’s action displayed on a large screen. The goalkeeper initiated his dive either before, at or after the ball was struck. The percentage of balls shot to the empty half of the goal was not above chance when the participants could only rely on predictive information. Gaze patterns suggested that the need to fixate the target location to maintain aiming accuracy hindered perceptual anticipation. It is argued that penalty-takers should select a target location in advance of the run-up to the ball and disregard the goalkeeper’s actions.
Bert Steenbergen and John van der Kamp
We investigated attentional processes that support the performance of high-skilled soccer players with hemiparetic cerebral palsy. Participants (N = 10) dribbled a slalom course as quickly and accurately as possible under two attentional-focus manipulation conditions. In the task-relevant focus condition, they attended to the foot that was in contact with the ball, whereas in the task-irrelevant focus condition, they monitored a series of words played on a tape. The time taken to complete the slalom course was registered. Performances of individuals with left and right hemiparesis were compared to explore differential effects of hemispheric lesion. The high-skilled players with congenital hemiparesis showed similar attentional-focus effects as those previously reported in the literature for high-skilled players without neurological disorders (Beilock et al., 2002; Ford et al., 2005). Task-relevant focus increased dribbling time, whereas a task-irrelevant focus did not result in a significant change in dribbling time. These findings generalized to each of the five participants with left hemiparesis (i.e., damage to the right hemisphere). By contrast, the effects of a task-relevant focus were less consistent for participants with right hemiparesis (i.e., left-hemisphere damage). This corroborates suggestions that the reinvestment of procedural knowledge is a left-lateralized function. The implications for the training of individuals with congenital brain damage are discussed.
Femke van Abswoude, John van der Kamp and Bert Steenbergen
Effective learning methods are essential for motor skill development and participation in children with low motor abilities. Current learning methods predominantly aim to increase declarative knowledge through explicit instructions that necessitate sufficient working memory capacity. This study investigated the roles of declarative knowledge and working memory capacity in explicit motor learning of children with low motor abilities. We studied both acquisition performance (i.e., performance during practice) and learning (i.e., the improvement in performance from pretest to posttest). After practice with explicit instructions, children with low motor abilities showed significant learning, albeit that improvement was relatively small. However, working memory capacity and declarative knowledge did not predict learning. By contrast, working memory capacity and declarative knowledge did predict performance during practice. These findings suggest that explicit instructions enhance motor performance during practice, but that motor learning per se is largely implicit in children with low motor abilities.
Geert J.P. Savelsbergh and John Van der Kamp
The Smeets and Brenner view on grasping is simple: grasping is in fact pointing. In our comments we examine the model beyond the reach-to-grasp task namely, by grasping (without reaching) of moving objects and eating. The model fits the data of both tasks. Although generalization of a model to different tasks usually strengthens its acceptance, in the present case it reveals its shortcomings, namely, both tasks include a clear grasping component that is hard to accept as pointing.
Raimey Olthuis, John van der Kamp, Koen Lemmink and Simone Caljouw
By assessing the precision of gestural interactions with touchscreen targets, the authors investigate how the type of gesture, target location, and scene visibility impact movement endpoints. Participants made visually and memory-guided pointing and swiping gestures with a stylus to targets located in a semicircle. Specific differences in aiming errors were identified between swiping and pointing. In particular, participants overshot the target more when swiping than when pointing and swiping endpoints showed a stronger bias toward the oblique than pointing gestures. As expected, the authors also found specific differences between conditions with and without delays. Overall, the authors observed an influence on movement execution from each of the three parameters studied and uncovered that the information used to guide movement appears to be gesture specific.
Matt Dicks, Chris Pocock, Richard Thelwell and John van der Kamp
Wim H. van Lier, John van der Kamp and Geert J.P. Savelsbergh
We assessed how golfers cope with the commonly observed systematic overshoot errors in the perception of the direction between the ball and the hole. Experiments 1 and 2, in which participants were required to rotate a pointer such that it pointed to the center of the hole, showed that errors in perceived direction (in degrees of deviation from the perfect aiming line) are destroyed when the head is constrained to move within a plane perpendicular to the green. Experiment 3 compared the errors in perceived direction and putting errors of novice and skilled players. Unlike the perceived direction, putting accuracy (in degrees of deviation from the perfect aiming line) was not affected by head position. Novices did show a rightward putting error, while skilled players did not. We argue that the skill-related differences in putting accuracy reflect a process of recalibration. Implications for aiming in golf are discussed.
Martina Navarro, Nelson Miyamoto, John van der Kamp, Edgard Morya, Ronald Ranvaud and Geert J.P. Savelsbergh
We investigated the effects of high pressure on the point of no return or the minimum time required for a kicker to respond to the goalkeeper’s dive in a simulated penalty kick task. The goalkeeper moved to one side with different times available for the participants to direct the ball to the opposite side in low-pressure (acoustically isolated laboratory) and high-pressure situations (with a participative audience). One group of participants showed a significant lengthening of the point of no return under high pressure. With less time available, performance was at chance level. Unexpectedly, in a second group of participants, high pressure caused a qualitative change in which for short times available participants were inclined to aim in the direction of the goalkeeper’s move. The distinct effects of high pressure are discussed within attentional control theory to reflect a decreasing efficiency of the goal-driven attentional system, slowing down performance, and a decreasing effectiveness in inhibiting stimulus-driven behavior.
Geert J.P. Savelsbergh, John van der Kamp and Walter E. Davis
Twenty-one children with Down syndrome (DS) and 20 without disability, ages 3 to 11 years, completed the experiment in which they were asked to grasp and lift cardboard cubes of different sizes (2.2 to 16.2 cm in width). Three conditions were used: (a) increasing the size from the smallest to the largest cube, (b) decreasing the size from the largest to the smallest, and (c) a random order of sizes. Children with DS were found to have smaller hand sizes in comparison to age-matched children without DS. In addition, the shift from one-handed to two-handed grasping appeared at a smaller cube size for children with DS than for children without DS. However, when the dimensionless ratio between object size and hand size was considered, the differences between groups disappeared, indicating that the differences in grasping patterns between children with and without DS can be attributed to differences in body size.
Matthieu M. de Wit, Rich S.W. Masters and John van der Kamp
Based upon evidence that vision for action has quicker access to visual information than vision for perception, we hypothesized that the two systems may have differentiated visual thresholds. There is also evidence that, unlike vision for perception, vision for action is insensitive to cognitive dual-task interference. Using visual masking, we determined the visual thresholds of 15 participants in a perception task, an action task and an action plus concurrent cognitive secondary task. There was no difference in threshold between the perception task and the action task, but the action plus concurrent secondary task was accompanied by a greater visual threshold than both the perception task and the action task alone, indicating dual-task interference. The action task was thus most likely informed by vision for perception. The implications of these results are reviewed in the context of recent discussions of the two visual systems model.