Dependence of asymmetrical interference on task demands and hand dominance in bimanual isometric force tasks

This study investigated the asymmetry of bilateral interference in a bimanual isometric force pulse task and the relation of the degree of interference with the asymmetry of the force levels and the hand dominance. One hand produced force pulses with the same peak force target, while the other hand produced different peak forces in blocked conditions with force target ratios between the hands that ranged from 1:1 to 16:1. There was asymmetric interference between the hands in that the hand performing the same peak forces showed stronger (i.e., higher bias and variable error) interference with the hand performing the different peak force than vice versa. The force-time properties also correlated more strongly when the different peak forces were generated by the left non-dominant than the right dominant hand. With increasing peak force ratios, the extent of interference became stronger and plateaued around the force ratio of 8:1 indicating a boundary condition to the asymmetric interference between hands. The results extend to bimanual isometric force control the dependence of bilateral asymmetric interference on task demands and hand dominance and provide further evidence on the degree of bilateral interference with task asymmetry.