Featured here is the Vladmir Tsarkov, the “Electric Juggler,” who despite his stage name doesn’t feature electricity in his act. His act is impressive, and when he does mistime a catch, he graciously recovers–quite the showsman.
Asymmetric coordination, doing two different things simultaneously, is difficult for a lot of people, which explains the awe jugglers inspire by their masterful coordination. Turns out directing opposite hands to different tasks is hard not because the brain has to deal with 2 tasks instead of 1 but because the brain actually combines 2 distinct tasks into 1. Whether the asymmetric coordination is successful depends on how well the 2 tasks are combined.
Generally human movement is modeled using Fitts’s Law (mathematics below). In essence, how much time a task takes depends on the difficulty of the task.
Neurophysiologists out of the University of Connecticut postulate how multiple unconnected tasks fit in with Fitts’s Law. They suggest instead of multiple tasks being processed simultaneously and independently as traditionally thought, independent tasks are merged into a single compound task.
Researchers used moving targets of variable size and speed and had subjects point to 2 targets simultaneously using different hands. When one hand dealt with a difficult task (small target moving quickly), the other hand slowed down. Both hands reach peak acceleration simultaneously and committed motions are coordinated.
[The] brain produces simultaneity of action not by controlling each limb independently, but by organizing functional groupings of muscles that are constrained to act as a single unit.