Aging affects attunement in perceiving length by dynamic touch

Earlier studies have revealed age-dependent differences in perception by dynamic touch. In the present study, we examined whether the capacity to learn deteriorates with aging. Adopting an ecological approach to learning, the authors examined the process of attunement—that is, the changes in what informational variable is exploited. Young and elderly adults were trained to perceive the lengths of unseen, handheld rods. It was found that the capacity to attune declines with aging: Contrary to the young adults, the elderly proved unsuccessful in learning to detect the specifying informational variables. The fact that aging affects the capacity to attune sets a new line of research in the study of perception and perceptual-motor skills of elderly. The authors discuss the implications of their findings for the ongoing discussions on the ecological approach to learning

The Role of Task Difficulty in Learning a Visuomotor Skill

NTRODUCTION: Task difficulty affects the amount of interpretable information from a task, which is thought to interfere with motor learning. However, it is unclear whether task difficulty in itself is a stimulus for motor learning because the experimental evidence is mixed in support of the optimal challenge point framework that predicts one specific level of task difficulty to produce the greatest magnitude of motor learning. PURPOSE: We determined the effects of functional task difficulty on motor skill acquisition, retention, and transfer. METHODS: Healthy young participants (N = 36) learned a mirror star-tracing task at a low, medium, or hard difficulty level defined by the bandwidth of the star. We measured skill acquisition, retention, and transfer to untrained difficulty levels, as well as the perceived mental workload during the task. RESULTS: Task difficulty affected motor performance, but did not affect motor learning and transfer. For the groups that practiced the task at the medium and hard but not at the low difficulty level, initial skill level correlated with the magnitude of learning. CONCLUSIONS: The optimal challenge point framework does not capture the complex relationship between task difficulty and motor learning. Previously reported effects of task difficulty on the magnitude of motor learning are probably mediated by perceived mental workload. Task difficulty did not affect the magnitude of visuomotor skill learning but it affected how learning occurred. The data have implications on how athletes learn new motor skills and patients relearn injury-impaired motor skills during rehabilitation

An Examination of the International Problems within “Tsūshōshi” Policy : Focusing on the Matter of Niigata

論文Article

People favour imperfect catching by assuming a stable world

The visual angle that is projected by an object (e.g. a ball) on the retina depends on the object's size and distance. Without further information, however, the visual angle is ambiguous with respect to size and distance, because equal visual angles can be obtained from a big ball at a longer distance and a smaller one at a correspondingly shorter distance. Failure to recover the true 3D structure of the object (e.g. a ball's physical size) causing the ambiguous retinal image can lead to a timing error when catching the ball. Two opposing views are currently prevailing on how people resolve this ambiguity when estimating time to contact. One explanation challenges any inference about what causes the retinal image (i.e. the necessity to recover this 3D structure), and instead favors a direct analysis of optic flow. In contrast, the second view suggests that action timing could be rather based on obtaining an estimate of the 3D structure of the scene. With the latter, systematic errors will be predicted if our inference of the 3D structure fails to reveal the underlying cause of the retinal image. Here we show that hand closure in catching virtual balls is triggered by visual angle, using an assumption of a constant ball size. As a consequence of this assumption, hand closure starts when the ball is at similar distance across trials. From that distance on, the remaining arrival time, therefore, depends on ball's speed. In order to time the catch successfully, closing time was coupled with ball's speed during the motor phase. This strategy led to an increased precision in catching but at the cost of committing systematic errors

The time course of amplitude specification in brief interceptive actions

The interception of fast moving objects typically allows the object to be seen for only a short period of time. This limits the time available to prepare the movement. To deal with short preparation intervals, performers are likely to prepare a motor program in advance. Although motor preparation may begin before the target is seen, accuracy requires that certain program parameters are determined from observations of the target. In the experiments reported here we sought to determine the last moment at which information about the distance to move (amplitude) can be incorporated into a program. We employed an empirical protocol that allowed us to examine whether new amplitude information is incorporated discretely or continuously into the program during short intervals prior to movement onset (MO)-the preparation interval. Participants were trained to hit targets at two different distances with movements of a specific duration (180 ms): targets were moving in "Experiment 1" and stationary in "Experiment 2". This method permitted an estimate of MO time. Preparation intervals were manipulated by delivering a stimulus cue for movement amplitude at varying times prior to the estimated MO. Results demonstrated that amplitude information could be effectively incorporated into the program provided the preparation interval was greater than about 200 ms. In addition, the results indicated that amplitude was specified predominantly in a discrete manner, though the number of responses directed towards a central default amplitude suggest that the distance between targets was near to a threshold for continuous specification