Effects of Transformed Visual-Motor Spatial Mappings and Droplines on 3-D Target Acquisition Strategy and Performance

This study investigated effects of transformed visual-motor mappings and a depth cue dropline on a 3-D target acquisition task. A cursor and target were displayed within a 3-D reference framework “Box” and participants were instructed to move the cursor into the target as quickly and accurately as possible by manipulating a 3-D input device called a “Spaceball.” The Box was presented with several lateral orientations. By tying the Spaceball movements to the frame of reference defined by the Box, the visual-motor mapping was transformed. Additionally, a depth cue dropline was manipulated. With the transformed mappings, movement times and path lengths to acquire the targets increased as the Box rotation angle increased. Droplines reduced movement times and path lengths. Participants' general acquisition strategy was to sequentially acquire the azimuth, elevation, and then range dimensions of the target, i.e., first visually overlapping the target with the cursor, and then acquiring the target along the line of the sight.