This study is focused on the attainment and retention of coordinated rhythmic movements. Specifically, the study assesses the effect of perceptual learning in relation to the demonstration of the movement. Through previous studies, researchers have proved that movements at 0 º and 180 º are stable and can be spontaneously performed without much occurrence of phase variability. Movements at 90 º however, have exhibited an unstable result, concluding that this movement would have to be learned before attainment could be achieved.
The learning of a novel movement based on its stability is not simply attained through physical practise, relying solely on the limbs experience of the movement. Instead, perceptual consequences of the coordinated movement along with transformed feedback results in a non-0 º coordinated movement to be stabilised. Reasons as to why performance at 0 º is easily performed as opposed to other relative phases is due to the essential information being detected more promptly. Therefore, improvement in stability in novel coordination is the participants’ ability to detect essential information through his/her perceptual ability. This study’s prediction is that if the participant is able to improve his/her ability at detecting the essential information then an improvement in stability at 90 º will occur.
12 participants (22-54 years old), half of which were assigned to an experimental group and the other to a controlled group. There were two experimental tasks: two alternative forced choice judgments and coordinated rhythmic movement. Also included were assessment and training sessions. The assessment session included judgment trials and movement trials without feedback; and the training session consisted only of judgement trials with feedback. The controlled group did not participate in the training sessions and received no feedback. There were 21 different trial types regarding judgement trials- 10 different differences x 2 orders and a catch trial. Demonstration was given at the start of the assessment, without feedback throughout session. During the training session participants performed 12 blocks of “choose 90 º” with feedback; these were compared to four other phases. As sessions progressed, discrimination was made harder. If response was correct, they were told; if incorrect, they were given an example of 90 º. Performance during training determined whether participants progressed to a harder training session; however, after four repetitions, they were automatically progressed. During movement trials, force feedback feature was disabled and participants were seated comfortably controlling joystick without actually seeing it. To dots were displayed on the computer screen; top dot was under control of the computer and the bottom dot was controlled by the participant. The computer recorded joystick and computer controlled dots.
Repeated measures ANOVA of the judgement results revealed that participants learned as a result of the training they had received; showing that there was a significant difference for baseline vs. post training at 90 º, however, there was no significant difference when analysing 180 º. A repeated ANOVA was performed on the median proportion of time on task with the tolerance set at 20 º (movement task); two within subject factors were noted: phase levels and session levels. The study found that stability at 90 º improved for the experimental group after training was given. The experimental group showed a main effect of phase as well as an interaction between phase and session while the control group only showed an effect of phase.
This experiment shows that the perception-action couples aid the learning of a coordinated novel movement. This was determined through thorough testing on the experimental and control groups in which the control group exhibited no significant result without perceptual training. The study showed that once perceptual ability was improved, movement stability had been increased, which strongly supports the hypothesis that movement stability is a function of perceptual ability. Perception-action is a system in which there are informational and motor components which contribute towards the overall behaviour of the system.