Figure 3.

Movement initiation times and directions recorded from a single subject (CK) for all trials in a session of experiment 2. Dashed lines indicate the normalized direction of the causal (0°) and noncausal (90°) trajectory, and the gray shaded region indicates the defined predictive zone. The launch target collided with the tool and the reaction target started moving at time 0. Note the scale difference between the left and right side panels. A, Smooth pursuit onset times during standard trials. The vast majority of movements began in the predictive zone. Note that the direction cluster is noticeably closer to 0 than 90°. B, Pursuit onset times during control (no-tool) trials. The direction bias evident in the standard trials is absent. C, Saccade onset times during standard trials. Early saccades (< −100 ms) were often refixations with randomly distributed directions, while late saccades (> 100 ms) were usually visually guided and directed toward the reaction target. Note that late saccades in the causal direction tended to begin slightly earlier. D, Saccades during no-tool trials. The early movement bias in the causal direction is no longer present, but otherwise the pattern of movements is similar to that of the standard trials.