Perception
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A human observer can smoothly pursue her/his own voluntarily moved hand with the eyes in total darkness. The effects of a perceived stationary surface during ocular pursuit of the invisible hand were investigated. ⋯ It was found that smooth pursuit of the invisible hand occurred in the Ganzfeld as well as in total darkness, but was replaced by frequent saccades when a stationary surface was perceived through either the visual or the tactile sense. The results obtained with a Ganzfeld suggest that light alone does not prevent smooth pursuit of the invisible hand, and those obtained with a stationary surface suggest that perception of such a surface prevents smooth pursuit of the invisible hand and evokes saccades, regardless of the sense modality.