Ebbinghaus visual illusion: no robust influence on novice golf-putting performance.

Do visual illusions reliably improve sports performance? To address this issue, we used procedures inspired by Witt et al. (Psychol Sci 23:397-399, 2012) seminal study, which reported that putting on a miniature golf course was positively influenced by an increase in apparent hole size induced by the Ebbinghaus visual illusion. Because Witt et al.'s motor task-putting golf balls toward a hole from the distance of 3.5 m-was impossible for participants who were novices in golf (Experiment 1a), we decided to shorten the putting distance (i.e., 2 m instead of 3.5 m) in Experiment 1b. Otherwise, this second experiment closely followed every other aspects of Witt et al.'s procedure (i.e., one small or one standard golf hole surrounded by a ring of small or large circles). However, this attempt to replicate Witt et al.'s findings failed: the Ebbinghaus illusion significantly influenced neither hole perception nor putting performance. In two subsequent experiments, we encouraged the emergence of the effect of the illusion by simultaneously presenting both versions of the illusion on the mat. This major adaptation successfully modified the perceived size of the hole but had no impact on putting performance (Experiment 2), even when the putting task was made easier by shortening the putting distance to only 1 m (Experiment 3). In the absence of detectable effects of the illusion on putting performance, we conclude that the effects of visual illusions on novice sports performance do not represent a robust phenomenon.

Effects of dual tasking on postural and gait performances in children with cerebral palsy and healthy children.

Simultaneous execution of motor and cognitive tasks is embedded in the daily life of children. 53 children of 7-12 years and 22 adults (study 1), 20 healthy children and 20 children of 7-12 years with cerebral palsy (study 2) performed a Stroop-animal task simultaneously with a standing or a walking task in order to determine the attentional demand of postural control and locomotion. Dual-task cost decreased with advancing age in healthy children during balance. CP and healthy children were similarly affected by dual-task constraints during standing and walking. Children with diplegia were more affected by the DT during the postural task than children with hemiplegia. We found that adults could benefit from dual-tasking for standing. The integrated model of task prioritization might explain our results regarding postural reserve of each population.

Intact Procedural Knowledge in Patients with Alzheimer's Disease: Evidence from Golf Putting.

Can Alzheimer's disease (AD) patients efficiently learn to perform a complex motor skill when relying on procedural knowledge? To address this question, the authors compared the golf-putting performance of AD patients, older adults, and younger adults in 2 different learning situations: one that promotes high error rates (thus increasing the reliance on declarative knowledge) or one that promotes low error rates (thus increasing the reliance on procedural knowledge). Motor performance was poorer overall for AD patients and older adults relative to younger adults in the high-error condition but equivalent between similar groups in the low-error condition. Also, AD patients in the low-error condition had better performance at the final putting distance relative to those in the high-error condition. This performance facilitation for AD patients likely stems from intact procedural knowledge.

Attentional load of walking in children aged 7-12 and in adults.

The amount of attentional resources necessary to walk in children, and how they evolve during childhood remains unclear. This study examined children's gait parameters in different dual-task conditions. 53 children, divided into two age groups (7-9 and 10-12 years old), and 18 adults walked on a mat in three different cognitive conditions: watching a video (video condition), listening its soundtrack (audio condition), and without any additional task (control condition). Questions were asked at the end of the video and audio conditions to make sure that participants were paying attention to the stimuli. A GAITRite® system was used for recording the gait data. Results showed an increase of velocity and step duration, and a decrease of cadence and percentage of double limb support duration from 7 years of age to adulthood during dual-task walking compared with single-task walking. This improvement seemed to be linear from 7 years to adults' age. The interference of dual-task on gait was larger for the video than for the auditory task and decreased with age. We concluded that walking requires a significant amount of attentional resources in children and that children rely more than adults on visual processes for walking.

Visual illusions can facilitate sport skill learning.

Witt, Linkenauger, and Proffitt (Psychological Science, 23, 397-399, 2012) demonstrated that golf putting performance was enhanced when the hole was surrounded by small circles, making it look larger, relative to when it was surrounded by large circles, making it look smaller. In the present study, we examined whether practicing putting with small or large surrounding circles would have not only immediate effects on performance, but also longer-lasting effects on motor learning. Two groups of nongolfers practiced putting golf balls to a 10.4-cm circle ("hole") from a distance of 2 m. Small or large circles were projected around the hole during the practice phase. Perception of hole size was affected by the size of the surrounding circles. Also, self-efficacy was higher in the group with the perceived larger hole. One day after practice, participants performed the putting task, but without visual illusions (i.e., a retention test). Putting accuracy in retention was greater for the group that had practiced with the perceived larger hole. These findings suggest that the apparently larger target led to the more effective learning outcome.

Lost ability to automatize task performance in old age.

Can elderly adults automatize a new task? To address this question, 10 older adults each performed 10,080 training trials over 12 sessions on an easy but novel task. The psychological refractory period (PRP) procedure was then used to evaluate whether this highly practiced task, when presented as task 2 along with an unpracticed task 1, could proceed automatically. If automatic, task 2 processing should bypass the bottleneck and, therefore, not be delayed while central attention is devoted to task 1, yielding little dual-task interference. This is exactly what Maquestiaux, Laguë-Beauvais, Ruthruff, and Bherer (Memory and Cognition 36:1262-1282, 2008) previously observed for almost all younger adults, even with half the training on a more difficult task. Although extensive training reduced older adults' reaction times to only 307 ms, a value virtually identical to that attained by Maquestiaux et al.'s (Memory and Cognition 36:1262-1282, 2008) younger adults, the highly practiced task 2 was slowed by 485 ms in the dual-task PRP procedure. Such a large slowing in older adults is striking given the easy tasks and massive amounts of practice. These findings demonstrate a qualitative change with age, in which older adults lose the ability to automatize novel tasks, which cannot be attributed merely to generalized cognitive slowing.

Novice motor performance: better not to verbalize.

Offline verbalization about a new motor experience is often assumed to positively influence subsequent performance. Here, we evaluated this presumed positive influence and whether it originates from declarative or from procedural knowledge using the explicit/implicit motor-learning paradigm. To this end, 80 nongolfers learned to perform a golf-putting task with high error rates (i.e., explicit motor learning), and thus relied on declarative knowledge, or low error rates (i.e., implicit motor learning), and thus relied on procedural knowledge. Afterward, they either put their memories of the previous motor experience into words or completed an irrelevant verbal task. Finally, they performed the putting task again. Verbalization did not improve novice motor performance: Putting was impaired, overall, and especially so for high-error learners. We conclude that declarative knowledge is altered by verbalization, whereas procedural knowledge is not.

Age effects shrink when motor learning is predominantly supported by nondeclarative, automatic memory processes: evidence from golf putting.

Can motor learning be equivalent in younger and older adults? To address this question, 48 younger (M = 23.5 years) and 48 older (M = 65.0 years) participants learned to perform a golf-putting task in two different motor learning situations: one that resulted in infrequent errors or one that resulted in frequent errors. The results demonstrated that infrequent-error learning predominantly relied on nondeclarative, automatic memory processes whereas frequent-error learning predominantly relied on declarative, effortful memory processes: After learning, infrequent-error learners verbalized fewer strategies than frequent-error learners; at transfer, a concurrent, attention-demanding secondary task (tone counting) left motor performance of infrequent-error learners unaffected but impaired that of frequent-error learners. The results showed age-equivalent motor performance in infrequent-error learning but age deficits in frequent-error learning. Motor performance of frequent-error learners required more attention with age, as evidenced by an age deficit on the attention-demanding secondary task. The disappearance of age effects when nondeclarative, automatic memory processes predominated suggests that these processes are preserved with age and are available even early in motor learning.

[Use of nondeclarative and automatic memory processes in motor learning: how to mitigate the effects of aging]. / Utilisation des processus mnésiques non déclaratifs et automatiques dans l'apprentissage moteur: comment atténuer les effets du vieillissement.

Does normal aging inexorably lead to diminished motor learning abilities? This article provides an overview of the literature on the question, with particular emphasis on the functional dissociation between two sets of memory processes: declarative, effortful processes, and non-declarative, automatic processes. There is abundant evidence suggesting that aging does impair learning when past memories of former actions are required (episodic memory) and recollected through controlled processing (working memory). However, other studies have shown that aging does not impair learning when motor actions are performed non verbally and automatically (tapping procedural memory). These findings led us to hypothesize that one can minimize the impact of aging on the ability to learn new motor actions by favouring procedural learning. Recent data validating this hypothesis are presented. Our findings underline the importance of developing new motor learning strategies, which "bypass" declarative, effortful memory processes.