Postural stability and hand preference as constraints on one-handed catching performance in children

Effects of postural state and hand preference as constraints on 1-handed catching performance were investigated in different ability groups of children aged 9-10 years. On the basis of pretest data, the authors classified 48 participants into groups of good, intermediate, and poor catchers (n = 16 in each) and asked them to perform 1-handed catches with their preferred and nonpreferred hands while standing and sitting. The good catchers' performance was not affected by the imposed postural constraints but did improve when they used the preferred hand. A similar effect of hand preference was evident in the intermediate and poor catchers, but there was also an effect of postural constraint. Independent of hand preference, intermediate catchers' performance while seated improved significantly compared with that during standing. For poor catchers, there was an interaction between hand preference and posture; significant improvement was evident only when they used the preferred hand in the sitting condition. The finding that manipulation of posture and hand preference affected performance outcomes indicates that perceptual skill is not the only influence on catching performance in children. Manipulation of those key constraints may facilitate the acquisition of catching skill, but more research is needed to determine the permanence of those effects.     

Postural Stability and Hand Preference as Constraints on One-Handed Catching Performance in Children

Effects of postural state and hand preference as constraints on 1-handed catching performance were investigated in different ability groups of children aged 9-10 years. On the basis of pretest data, the authors classified 48 participants into groups of good, intermediate, and poor catchers (n = 16 in each) and asked them to perform 1-handed catches with their preferred and nonpreferred hands while standing and sitting. The good catchers' performance was not affected by the imposed postural constraints but did improve when they used the preferred hand. A similar effect of hand preference was evident in the intermediate and poor catchers, but there was also an effect of postural constraint. Independent of hand preference, intermediate catchers' performance while seated improved significantly compared with that during standing. For poor catchers, there was an interaction between hand preference and posture; significant improvement was evident only when they used the preferred hand in the sitting condition. The finding that manipulation of posture and hand preference affected performance outcomes indicates that perceptual skill is not the only influence on catching performance in children. Manipulation of those key constraints may facilitate the acquisition of catching skill, but more research is needed to determine the permanence of those effects.     

Specificity of practice in a ball interception task.

Learning of an aiming task has been shown to be specific to the sources of afferent information available during practice. However, this has not been the case when a one-hand ball-catching task has been used. The goal of the present study was to determine the cause of these conflicting results. Participants practiced an interception task in either a normal vision condition or a ball-only condition. They were all then transferred to the ball-only condition, using either the same ball trajectories as in acquisition or different ones. Being transferred from a normal vision condition to a ball-only condition resulted in a significant increase in spatial interception errors, thus supporting the specificity of practice hypothesis. Using new ball trajectories in transfer caused a significant increase in error for all participants. The pattern of errors observed when new ball trajectories were used suggests that participants had difficulty correlating information about the location of their arm via proprioception and a combination of retinal and extra-retinal information about the ball trajectory.     

Contextual interference effects in sequence learning for young and older adults

Practice of different tasks in a random order induces better retention than practicing them in a blocked order, a phenomenon known as the contextual interference (CI) effect. Our purpose was to investigate whether the CI effect exists in sequence learning, such that practicing different sequences in a random order will result in better learning of sequences than practicing them in blocks, and whether this effect is affected by aging. Subjects practiced a serial reaction time task where a set of three 4-element sequences were arranged in blocks or in a random order on 2 successive days. Subjects were divided into 4 groups based on a 2-GROUP (young or old) by 2-ORDER (random or blocked practice) between-subject design. Three days after practice (Day 5), subjects were tested with practiced and novel sequences to evaluate sequence-specific learning. The results replicate the CI effect in sequence learning in both young and older adults. Older adults retained sequences better when trained in a random condition than in a blocked condition, although the random condition incurs greater task switching costs in older adults during practice. Our study underscores the distinction between age-related effects on learning vs. performance, and offers practical implications for enhancing skill learning in older adults.     

Retention of bilateral performance as a function of practice order

The purpose of this study was to investigate the effect of practice order and initial performance hand on the bilateral retention of a simple tracking skill for 44 undergraduate volunteers. The apparatus was a Lafayette Model 30014 photoelectric rotary pursuit. The circle template was employed with rotation speed set at 20 rpm. Subjects were given 20-sec. trials and required to reach a criterion of 70% time on target twice in succession with both hands. For original practice, subjects were randomly assigned to one of four practice groups: preferred serial, non-preferred serial, preferred sequence and non-preferred sequence. Subjects' performance was recorded as the number of trials required to achieve criterion for both hands. One month later subjects were retested and scored in the same manner. A 2 X 2 X 2 analysis of variance with repeated measures on the last factor was used to determine the effects of initial hand, order of practice, testing periods, and the appropriate interactions. The results indicated that subjects' performance for the two testing periods differed significantly; retest was superior. Order of practice was significant and the sequential order more efficient during both learning and retest.     

Intermittent vision and one-handed catching: the effect of general and specific task experience

In Experiment 1, 15 skilled and 15 less skilled participants performed 1-handed catching in 4 conditions. For both groups, catching performance deteriorated significantly when no visual information was available for 40 ms between 20-ms visual samples (20/40) and continued to decline with subsequent increases in the duration between visual samples (i.e., 20/80 and 20/120). In Experiment 2, 50 participants performed a pretest and a posttest in a 20/80 condition, separated by 4 blocks of practice (N=80). Participants who practiced with intermittent vision (20/40, 20/80, and 20/120) exhibited a significant improvement between pretest and posttest. Although general practice with intermittent vision enabled some adaptation, posttest performance did not equal performance in the 1st block of continuous vision.     

Effect of instructional units on the analysis of related and unrelated skills

84 majors in elementary education were divided into three groups, one control group and two experimental groups. The control group received no instruction in skill analysis while the experimental groups were instructed via videotape in either the instep kick in soccer or in throwing, catching, and striking skills. All three groups were given a skill-analysis test composed of throwing, catching, and striking skills. Statistical analysis yielded significant effect for those who viewed the throwing, catching, and striking videotape. No effect was found for the control group or the group who viewed the soccer-instep videotape. The results suggest specificity may be as important in skill analysis as in acquisition.     

The role of binocular information in ball catching

The role of binocular vision in a ball-catching task involving spatial uncertainty was examined in three experiments. In all three experiments, subjects' catching performance was evaluated during monocular and binocular viewing, in normal room lighting and in complete darkness with a luminescent ball. Subjects' performance was found to be significantly better with binocular than with monocular vision, especially under normal lighting conditions. In the second and third experiments, catching performance was evaluated in the presence of minimal visual frames, consisting of a series of light-emitting diodes (LEDs). In Experiment 2, the visual frame consisted of a single plane of LEDs, whereas in Experiment 3, the visual frame consisted of two planes of LEDs. Catching performance was found to be significantly better with the visual frame than in complete darkness, but this was true only for binocular viewing. This result supports the hypothesis that binocular convergence is used to scale perceived space and that this information enables subjects to contact the ball successfully. It was further found that postural sway varied between lighting conditions and that less sway was accompanied by higher performance. There was no effect of binocular viewing in this respect. In general, the results suggest two additive effects of viewing conditions: a direct effect of binocular vision on ball catching and an indirect effect of lighting on postural stability, which, in turn, affects catching performance.     

Effects of instruction and practice on ball catching skill: single-subject study of an 8-year-old.

An eight-year-old boy learned to make one-handed catches by involvement in three 30-min. periods of instruction and practice consisting of modelling, videotape-based performance feedback, and variable practice interspersed with videotaped assessments on seven consecutive days. An adult-like catching action (both hands) emerged in the second session and was used exclusively thereafter. Catching success at the second and third assessments improved from 40% (preferred hand) and 30% (non-preferred) to over 90% (both hands) on the final assessment. Following the intervention, success and the catching action were similar to those of skillful ten-year-old subjects observed in a previous study.     

Acquiring a cognitive skill with a new repeating version of the Tower of London task.

A computerized version of the Tower of London task was used to investigate cognitive skill learning. Thirty-six healthy volunteers were assigned to either a random condition (nonrecurring problems), or to a sequence condition in which, unbeknownst to the subjects, a repeating sequence of three problems was presented. Indices of execution, planning, and total time, as well as number of moves performed, were used to measure behavioural change. Subjects' performance improved in both conditions across blocks of practice. A distinct learning effect related to the repeating sequence was also observed. This suggests that a specific skill that reflects procedural learning of the strategies, rules, and procedures pertaining to repeating problems can develop over and above a more general skill at solving cognitive planning problems with practice.     

Contextual interference effect on acquisition and retention of pistol-shooting skills

The effects of contextual interference on learning pistol-shooting skills in a natural training environment were examined. The shooting skills consisted of three "stages" with different requirements for the skill variations commonly used in the field. 12 participants were randomly assigned into one of two practice conditions, blocked vs serial. Following a 20-min. safety and skill instructional session, Blocked group practiced 10 trials in a row at each stage, while Serial group performed 5 trials in a row for each of the three stages and then repeated the cycle. Both groups completed a total of 30 practice trials over the three stages. A 10-min. rest interval was provided prior to a retention test which included 9 trials (3 trials at each stage in a blocked format). Results based on the data of Stage III, the most complex skill among the three stages, showed a pattern consistent with previous findings that practicing in the serial schedule depressed performance during initial training but maintained the performance better at retention, relative to the blocked practice.     

Number of options in a movement sequence affects learners' behavior in a self-controlled practice condition

Self-controlling practice implies a process of decision making, which suggests that the options in a self-controlled practice condition could affect learners. The number of task components with no fixed position in a movement sequence may affect the way learners self-control their practice. A 200-cm coincident timing track with 90 light-emitting diodes (LEDs)--the first and the last LEDs being the warning and the target lights, respectively--was set so that the apparent speed of the light along the track was 1.33 m/sec. Participants were required to touch six sensors sequentially, the last one coincidently with the lighting of the target light (timing task). Group 1 (n = 55) had only one constraint, and were instructed to touch the sensors in any order, except for the last sensor which had to be the one positioned close to the target light. Group 2 (n = 53) had three constraints: the first two and the last sensor to be touched. Both groups practiced the task until timing error was less than 30 msec. on three consecutive trials. There were no statistically significant differences between groups in the number of trials needed to reach the performance criterion, but (a) participants in Group 2 created fewer sequences compared to Group 1, and (b) were more likely to use the same sequence throughout the learning process. The number of options for a movement sequence affected the way learners self-controlled their practice, but had no effect on the amount of practice to reach criterion performance.     

Imagery intervention in open and closed tennis motor skill performance

To assess use of imagery intervention in performance of two tennis motor skills the quasi-experimental design included a pre- and posttest and a control group. The tennis service shot and service receiving skill were selected as representative of open and closed skills, respectively. 48 subjects, male tennis players, whose ages ranged from 16 to 18 yr. (M = 17.2), were divided into two groups: (1) Technical practice only which was used as control group and (2) Imagery group who received both imagery and technical practice. Analysis of covariance showed a significant main effect for the imagery intervention on the closed skill (p = .002). Findings suggest that imaging a positive outcome may be more powerful in improving performance of closed skill movements than of open skill movements.     

The effects of reward and perception of competency upon intrinsic motivation

The effects of contingent and noncontingent reward upon subsequent performance on a decoding task were compared. The results indicated that reward had an overall detrimental effect. There was some evidence that contingent reward was more detrimental than noncontingent reward. The informational aspect of the reward was also varied. Subjects were made to feel either more competent than, equal to, or less competent than the average student. The competency manipulation did not affect subsequent performance. It did affect subjects' willingness to participate in a similar experiment in the future.     

Skill acquisition in music performance: relations between planning and temporal control

We investigated the acquisition of music performance skills in novice and expert pianists. Temporal disruptions in novice performances coincided with constraints in planning capacities. Child and adult pianists ranging in age (9-26 years), training (3-15 years) and sight-reading ability learned to perform a novel musical piece in eleven practice trials. Computer-detected pitch and timing errors revealed: (1) gradual improvements in performance tempo and pitch accuracy with skill level and practice, generally fitting a power function; (2) a relative-timing/pitch accuracy trade-off and high incidence of simultaneous pitch/time errors; (3) improvements in relative timing (temporal continuity, underlying beat, metrical structure) with skill and practice; and (4) increased anticipatory behavior and a greater range of planning with skill and practice. A strong positive relationship between the mastery of temporal constraints and planning abilities within performance suggests that these two cognitive indicators are closely related and may arise from segmentation processes during performance. Examination of sequence timing may explicate planning abilities that underlie many complex skills.     

材料呈现方式对初中生和大学生分类的影响

以初中和大学各60名学生为被试,a、b、c三套图片为材料,用A、B、C三种材料呈现方式,以分类的结果和解释的理由为依据,用一维特征、整体相似性、两阶段策略和其它分类作为因变量指标,采用混合设计,用SPSS对实验结果进行χ²检验。结果发现:(1)材料呈现方式对大学生分类结果影响显著,对初中生分类结果影响不显著;(2)初中生和大学生分类结果之间在B、C两种方式下,差异显著,在A方式下,差异不显著。     

Feedback and fidelity: Effects of contingent consequences on accuracy of imitation

Accuracy of imitation by sixty kindergarten subjects was examined using a task in which a female adult modeled a series of pegboard patterns and delivered accuracy-contingent feedback. Four methods of feedback and a nofeedback control were compared. All four feedback groups were more accurate than the control group. The feedback conditions were: positive only, negative only, positive and negative, and negative with correction. The last condition resulted in greater accuracy than the others, which did not differ. All groups, including the control, improved significantly over trials. Accuracy of performance on interspersed, nonfeedback trials was maintained by feedback to the other patterns. Finally, imitation of repeating stimulus patterns did not differ from performance with nonrepeating patterns.     

Effects of imposed delay of response and item complexity on auditory comprehension by aphasics

Ten aphasic and five control subjects were administered an auditory comprehension task similar to Levels I-IV of the Revised Token Test under conditions of 0, 5, 10, and 20 sec of imposed response delay. Responses were evaluated in terms of performance accuracy and response time. Aphasic subjects' response accuracy was significantly effected by an interaction between the length of delay imposed and the complexity of the stimulus. The aphasic group also demonstrated a significant main effect for item complexity. Control subjects' accuracy was not influenced by the treatment conditions. Latency measures indicated the aphasic subjects were slower to respond across all treatment conditions. Both groups' latency scores were significantly effected by item complexity. A comparison of mean latencies by condition did, however, suggest different patterns of response for the two groups. Results are discussed in terms of theoretical and clinical implications for the auditory comprehension deficits of aphasia.     

The effect of tire grip on learning driving skill and driving style: A driving simulator study

There is a need for training methods that improve the driving skill and driving style of novice drivers. Previous research in motor learning has shown that degrading the task conditions during practice can enhance long-term retention performance. Inspired by these findings, this study investigated the effects of the tire-road friction coefficient on learning a self-paced lane-keeping task in a driving simulator. A sample of 63 young and inexperienced drivers were divided into three groups, low grip (LG), normal grip (NG) and high grip (HG), who practiced driving with a friction coefficient of 0.45, 0.90, and 1.80, respectively. All groups drove six 8 min sessions on a road with curves in a rural environment: four practice sessions, an immediate retention session, and a delayed retention session on the next day. The two retention sessions were driven with normal-grip tires. The results show that LG drove with lower speed than NG during practice and retention. Transferring from the last practice session to the immediate retention session, LG’s workload decreased, as measured with a secondary task, whereas HG’s workload increased. During the immediate retention session, LG had less road departures than HG, but HG drove closer to the lane center in curves than the other two groups. HG reported elevated confidence during practice, but not in retention. In conclusion, this simulator-based study showed that practicing with low-grip tires resulted in lower driving speeds during retention tests, an effect which persisted overnight. These results have potential implications for the way drivers are trained.     

Constant or variable practice: recreating the especial skill effect

An especial skill occurs when performance of a single action from within a class of actions produces an advantage in performance. This advantage in a single action over others in the class is presumed to result from large amounts of practice performing the specific action (Keetch, Schmidt, Lee, & Young, 2005). In an experiment involving the learning of a basketball set shot, practice was manipulated to identify whether an especial skill effect emerges at the free-throw line as a result of constant practice conditions in novice performers. After a pretest, which involved set shots across five distances, participants were randomly assigned to one of two intervention groups. A constant practice group (n=10) performed 300 trials of the set shot at the 15 ft free throw line only, whereas a variable practice group (n=10) performed 300 trials across five distances. Shot accuracy increased for both groups as a result of practice at the 15' distance. However, on the posttest, a significant difference was reported between actual and expected scores for the constant practice group only. This finding provided evidence that an effect similar to that seen for especial skills emerges as a result of constant practice. Although an especial skill effect could result from massive amounts of practice, we show it can emerge as a result of short term repetitive practice, indicating that the type, rather than amount, of practice is important.