illustrates the experimental procedure.
The tested motor task was a visuomotor adaptation of handball free throws with prismatic glasses. Handball players (experts) and subjects without experience in ball sports (novices) were equally divided into two groups, a group receiving visual vector error feedback and binary error feedback (VE+BE), and a group receiving binary error feedback (BE), in a distinct phase of the experiment. The reduction to BE was made possible by shutter glasses obstructing vision. The visual shift induced by the prismatic glasses is indicated with dotted arrows for every phase of the experiment. The resultant throwing directions throughout the phase are displayed with the solid arrows. Starting with a series of baseline throws, all subjects first adapted to 16.7° visual displacement. Thereafter, this adaptation was reinforced in subjects with BE through auditory feedback about task success (binary error, BE). Subjects with VE+BE received full visual feedback about vector error (VE) and task success (BE) in this phase of the experiment. Adaptation to additional visual displacement of 5.1° (to a total displacement of 21.8°) followed for all subjects, prior to the no-vision phase and washout of the adaptation.