Fig. 5.

Results for one representative participant in the supplemental experiment that used a mixed design. Horizontal and vertical saccade amplitudes for one participant are plotted along with the fitted value of the multivariate linear model. Top, results for the control condition (with no internal motion); bottom, results for the double-drift condition (where the physical path was tilted to the left and the perceived path was vertical). Left panels correspond to the interceptive condition, and right panels correspond to the 1-s delay. The angle of the deviation of the recovered path from vertical (α) is indicated in each graph. For this participant, the orientation of the double-drift path that appeared vertical in the perceptual test was 50°. In the control condition, the angle of the recovered path is similar for the interceptive condition and the 1-s delay (60.1° and 63.7°, respectively) and is relatively close to the real angle of the physical path (50°). In the double-drift condition, there is a difference between the interceptive condition and the 1-s delay. In the interceptive condition, the angle of the recovered path (64.7°) is also close to the angle of the physical path (50°), whereas in the memory conditions, the angle of the recovered path (23.4°) is closer to vertical.