The effects of incongruent feedback on bimanual task performance

Previous studies analyzing the effects of incongruent visual and haptic feedback have found differences in the perceived stiffness of an object depending on what modality was delayed. These studies required only unilateral performance of the individual and did not measure functional task completion. Our study evaluated the effects of incongruent visual and haptic feedback during a bimanual pick and place task within a virtual environment using two Phantom Omnis. Subjects were asked to place three different colored spheres into matching colored baskets under various testing conditions. The testing conditions included various temporal delays in either the haptic feedback, visual feedback or both feedback modalities simultaneously. The amount of time required to complete the task as well as the number of spheres broken were recorded for each trial. The results show that delays in either or both of the feedback modalities had a negative effect on the subject´s ability to complete the task. The most detrimental effects on task performance were observed when both feedback modalities were simultaneously delayed 133 ms for both the completion time and number of broken spheres.