Horizontal saccades to dichoptically presented targets of differing disparities

Horizontal saccades were elicited to targets of various disparities displayed dichoptically. When the left eye and right eye targets were in the same hemifield, the resulting saccade demonstrated spatial averaging (42%, where 50% represents perfect averaging) between the left and right eye target positions. When the left eye and right eye targets were in opposite hemifields, the saccade was directed to one of the stimuli and was only minimally influenced by the presence of the other. This pattern is similar to that obtained when saccades are made to double targets, both of which are visible to both eyes. These data are discussed in terms of an ecological role for the global effect.