Brief bimanual force pulses: Correlations between the hands in force and time

Three experiments assessed coupling phenomena in the coordination of bimanu al force pulses. Experiment 1 required symmetric force pulses (equal target forces and rise times for both hands) using the index finger of each hand. As the authors expected, on the basis of bimanual pointing movement result s, this experiment revealed positive correlations between both the force ri se times and the force amplitudes of the two hands. Experiments 2 and 3 inc luded asymmetric conditions with different target force amplitudes (Experim ent 2) or target rise times (Experiment 3). In Experiment 2 force amplitude s but not rise times were fully decoupled in the asymmetric condition. In t he asymmetric condition of Experiment 3, however, neither rise times nor fo rce amplitudes were fully decoupled. The results suggest a hierarchical con trol structure with temporal control dominating nontemporal control of bima nual force coordination.