Skill acquisition as a function of age, hand and task difficulty
The relationship between motor performance and sequence learning were examined.
Experiment 1 established that older adults were worse at learning the serial order of a complex sequence. Experiment 2 found that participants showed impaired motor learning when the non-preferred hand was used. Experiment 3 confirmed that a detrimental effect on serial order learning occurs when motor demands increase (as the model predicted). These results suggest that sequence learning is constrained by an individual’s cognitive capacity but is also influenced by sensorimotor bandwidth.
Experiment 1 - A motor learning task was created using ‘KineLab’). Participants used a tablet PC and standard computer mouse to learn a sequence of movements each made between the centre and one of eight target locations on the screen. The task consisted of a series of ‘training’ and ‘test’ trials that alternated to allow 14 opportunities each for participants to practice and then reproduce the sequence (i.e. training trial, test trial x 14 repetitions = 28 trials in total). The same sequence was used across all the participants to ensure that there were no confounding effects created by sequences of differing difficulty.
Data: The following measures were calculated to examine speed and accuracy of recall (i.e. motor learning) in the test trials, and level of motor performance in the training trials.
(i) Recall during test trial measures: Number of moves recalled in the correct sequential order (Correctly Recalled; CR), with a maximum score of 30 (points were not deducted for incorrect moves but in the majority of cases the first error in the sequence marked the end of successful recall); Recall Movement Time (MTr) was the mean time (s) taken to move the mouse from the centre to a target box when recalling the sequence (i.e. a measure of recall speed).
(ii) Training trial measures: Path Length (PL) indicated the length of the path (mm) taken by participants throughout an entire training trial, thus providing a marker of movement accuracy (i.e. straight paths will be shorter) with longer paths suggesting the presence of error corrections; Training Movement Time (MTt) was the time (s) taken to complete a training trial from start to finish.
For the analysis of data from the test trials, mean values for CR and MTr across the first five trials (F5) and last five trials (L5) were calculated. These data were input into two separate mixed-model ANOVAs to compare speed and accuracy of sequence recall between the beginning and end trial blocks (i.e. to identify progression of learning from the first to second half of the task), and between the older and younger age groups. For the training trials, mean values for PL and MTt across the L5 trials were used as a baseline measure of motor performance.
Experiment 2 Analysis : Outcome measures were identical to those used in Experiment 1 (CR, MTr, PL and MTt). For the test trial analysis, mean scores across the L5 trials were calculated and two separate mixed-model ANOVAs applied in order to examine age and hand differences in motor learning (CR and MTr). Two further ANOVAs were carried out to identify the effects of hand and age on motor performance during the L5 trials of training (PL and MTt).
Experiment 3 Analysis : Outcome measures were identical to those used
in Experiments 1 and 2 (CR, MTr
for the recall at test analysis; PL and MTt
for the training trial analysis). For recall during test trials, mean scores
for CR and MTr across
the last five (L5) trials were calculated, and a One-Way ANOVA was performed on
each recall measure, to examine the effect of mouse orientation (R vs. S) on
motor learning. A One-Way ANOVA was also completed to identify the effects of
mouse orientation on motor performance during the L5 training trials (one for
each training measure: PL and MTt).