Monday, 26 March 2012

Kovacs, A. J., Buchanan, J. J., & Shea, C. H. (2009a). Bimanual 1:1 with 90° continuous phase

Kovac et al (2009a) performed a study looking at the effects of Lissajous feedback. 20 participants were asked to perform a 1:1 bimanual coordination task with a 90° relative phase. While doing this the participants received constant Lissajous feedback. This feedback was in the custom of a cursor signifying the joint position of the two limbs put over on a Lissajous template portraying the necessary phase relation between the limbs. When the left limb moved it moved the cursor vertically and when the right limb moved it moved the cursor horizontally. The results showed that the participants were reasonably effective in executing the coordination pattern that was required (variability and relative phase errors low), after only having 5 minutes of practice. When compared with results from participants who had many days of practice, the level of relative phase errors and variability was in fact lower. In this experiment an auditory metronome was not included and vision of the limbs was not allowed. When a metronome was introduced performance decreased as variability and relative phase errors increased considerably.

Other work by Kovac in 2009 (Kovac et al 2009b) showed that when participants are provided again with constant Lissajous feedback, they can successfully perform relative phases between 30° and 150° using only four minutes of practice at both separate relative phases. This and the study previously discussed, seems to suggest that Lissajous feedback inhibits a faster way of learning.

However a problem with the Kovac studies is that it was proved that participants became too heavily dependent on the Lissajous feedback. When the Lissajous feedback was removed performance decreased as there was higher relative phase error and variability. This outcome proposes that the Lissajous plot with cursor and template provided participants a platform by which they were able to notice their coordination mistakes and perform the required adjustments. This decrease in performance when the Lissajous feedback had been removed suggested that participants had not actually learnt the relative phase but instead had learned to use the constant information provided to perform the necessary coordination patterns. Participants had not developed an internal depiction of the task and therefore were reliant on the constant feedback and when that was removed they struggled with the task. This therefore suggests that constant feedback could indeed hinder learning.

No comments:

Post a Comment