Transsaccadic Memory for the Position of Stationary and Translating Biologicalmotion Walkers

Previous research demonstrated an advantage for translating objects over stationary objects in transsaccadic displacement detection. However, in some studies, this benefit was absent. The current study was designed in order to clarify the basis of these contradictory findings. To this end, the procedure of an experiment with a clear motion benefit was combined with the stimuli of a study in which the motion benefit was absent. Participants saccaded towards either a stationary or a translating point-light walker and had to detect the intrasaccadic displacement of either the saccade target or the saccade flanker. Intrasaccadic displacements of the translating walker were found to be easier to detect than displacements of the stationary walker. Furthermore, displacements of the saccade target walker were better detected than displacements of the flanking walker. Implications for the previously contradictory observations are discussed and an explanation is proposed emphasising the differential importance of spatiotopic coding when a viewer is engaged in smooth object pursuit rather than having a stable fixation before making a saccade towards a translating object.