Anticipatory spatial representation of natural scenes: Momentum without movement

Does mental representation of the immediate past contain anticipatory projec-tions of the future? In cases of representational momentum (RM), the last remem-bered location of a moving object is displaced farther along its path of motion. In boundary extension (BE), the remembered view of a scene expands to include a region just outside the boundaries of the original view. Both are “errors”, yet they make remarkably good predictions about the real world. The factors affecting these phenomena, the boundary conditions for their occurrence, and their gener-ality to non-visual senses (audition or haptics) are reviewed to determine if RM and BE are fundamentally related. In contrast to Hubbard’s (1995b) suggestion that they may share a common underlying mechanism, it is proposed instead that RM and BE are related in a more general sense and may be different instantiations of the dynamic nature of mental representation. A powerful means of exploring the nature of mental representation is to study the errors that perceivers share in common; representational momentum (RM) and boundary extension (BE) are two such errors and provide opportunities for understanding the mental representation of events that unfold over time. What is particularly interesting about these phenomena is that although in one sense they are errors (i.e., they differ from the physical stimulus), in another sense they provide remarkably accurate predictions about characteristics of the world that have not yet been perceived. In the case of RM, when a moving object vanishes, within moments, observ-ers misreport its last seen position as being farther along the path of motion than it actually was (Finke & Freyd, 1985; Freyd & Finke, 1984). In the case of BE