Change in effects of motor preparation due to priming as a function of the amount of practice]

The goal of the present experiment is to assess the effects of motor preparation on reaction time (RT) as a function of practice. We used a priming procedure to induce different levels of motor preparation. In reaction to a visual signal, the 16 participants had to respond with a flexion or an extension of the right or left wrist. Each participant performed 6120 successful trials divided into 34 experimental series. The first analysis of RT as a function of the type of cue (valid, neutral, or invalid) suggested that the time needed (a) to inhibit the prepared response and (b) to program the required one, remains stable throughout practice. A second analysis on the amount of information to be processed according to type of cue (0.42, 2.00, and 3.58 bits) indicated that central processing speed did not vary with practice. Indeed, only RT for the 0 bit condition decreased during the first 720 trials, suggesting that only the peripheral processes were influenced in early learning.     

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.     

Transfer of short-term motor learning across the lower limbs as a function of task conception and practice order

Interlimb transfer of motor learning, indicating an improvement in performance with one limb following training with the other, often occurs asymmetrically (i.e., from non-dominant to dominant limb or vice versa, but not both). In the present study, we examined whether interlimb transfer of the same motor task could occur asymmetrically and in opposite directions (i.e., from right to left leg vs. left to right leg) depending on individuals’ conception of the task. Two experimental conditions were tested: In a dynamic control condition, the process of learning was facilitated by providing the subjects with a type of information that forced them to focus on dynamic features of a given task (force impulse); and in a spatial control condition, it was done with another type of information that forced them to focus on visuomotor features of the same task (distance). Both conditions employed the same leg extension task. In addition, a fully-crossed transfer paradigm was used in which one group of subjects initially practiced with the right leg and were tested with the left leg for a transfer test, while the other group used the two legs in the opposite order. The results showed that the direction of interlimb transfer varied depending on the condition, such that the right and the left leg benefited from initial training with the opposite leg only in the spatial and the dynamic condition, respectively. Our finding suggests that manipulating the conception of a leg extension task has a substantial influence on the pattern of interlimb transfer in such a way that the direction of transfer can even be opposite depending on whether the task is conceived as a dynamic or spatial control task.     

Retrieval practice in motor learning

In this study we sought to determine whether testing promotes the generalization of motor skills during the process of encoding and/or consolidation. We used a dynamic arm movement task that required participants to reproduce a spatial-temporal pattern of elbow extensions and flexions with their dominant right arm. Generalization of motor learning was tested by the ability to transfer the original pattern (extrinsic transformation) or the mirrored pattern (intrinsic transformation) to the unpractised left arm. To investigate the testing effects during both encoding and consolidation processing, participants were administered an initial testing session during early practice before being evaluated on a post-practice testing session administered either 10 min (Testing-Encoding group) or 24 hr apart (Testing-Consolidation group), respectively. Control groups were required to perform a post-practice testing session administered after either a 10-min (Control-Encoding group) or 24-hr delay (Control-Consolidation group). The findings revealed that testing produced rapid, within-practice skill improvements, yielding better effector transfer at the 10-min testing for the Testing-Encoding group on both extrinsic and intrinsic transformation tests when compared with the Control-Encoding group. Furthermore, we found better performance for the Testing-Consolidation group at the 24-hr testing for extrinsic and intrinsic transformations of the movement pattern when compared with the Control-Consolidation group. However, our results did not indicate any significant testing advantage on the latent, between-session development of the motor skill representation (i.e., from the 10-min to the 24-hr testing). The testing benefits expressed at the 10-min testing were stabilised but did not extend during the period of consolidation. This indicates that testing contributes to the generalisation of motor skills during encoding but not consolidation.