Effects of integrated feedback and movement templates on discrete bimanual movements in simple reaction time

The purpose of the current study was to investigate whether integrated visual feedback and movement templates could facilitate bimanual movements with different patterns of spatiotemporal coupling and decoupling. Knowing when Lissajous feedback and movement templates improve bimanual movements, and when they do not, will help determine the mechanisms of task conceptualisation. We tested two bimanual asymmetric conditions where different movement templates were used to encourage the movements to travel different paths to the same targets. The asymmetric straight condition was the same as Shea, Boyle, and Kovacs (2012), and we predicted that we would replicate their results and find no temporal coupling. The novel asymmetric diagonal condition required movements with a 2:1 movement ratio (relative spatiotemporal coupling). Longer movement time and larger root-mean-square deviation of the trajectories suggested that asymmetric straight movements were more difficult than symmetric movements. Even longer movement times and fewer target hits suggested that asymmetric diagonal movements were more difficult than asymmetric straight movements. Lissajous feedback and movement templates made the difficult asymmetric movements possible. However, movements with relative spatiotemporal coupling were the most difficult and movements without temporal coupling were still more difficult than symmetric movements. We suggest that Lissajous feedback and movement templates improved the task conceptualisation, which eliminated or reduced the high-level cognitive constraints. The low-level neuromuscular constraints, however, persisted and these caused the increased difficulty for asymmetric movements. Improving the task conceptualisation can facilitate asymmetric movements. These asymmetric movements still have different difficulties and they are not as easy as symmetric movements.