Effects of temporal scaling and attention on the asymmetrical dynamics of bimanual coordination

Handedness and attentional asymmetries in bimanual rhythmic coordination were examined as a function of movement speed. In an in-phase 1:1 frequency locking task, left-handed and right-handed subjects controlled the oscillations of either the right or the left hand so as to contact spatial targets. The task was performed at three frequencies of coupled movement. Coordination dynamics incorporating the body's functional asymmetry predicted that left-handers and right-handers would deviate from zero relative phase in opposite directions, that the deviation would be greater for preferred-hand targeting, and that this deviation would be greater at higher movement frequencies. The results confirmed the major predictions and suggested that asymmetry due to handedness is magnified by attention.