SOME EFFECTS OF REPRESENTATIONAL FRICTION, TARGET SIZE, AND MEMORY AVERAGING ON MEMORY FOR VERTICALLY MOVING TARGETS

Observers viewed an animated ascending or descending target that varie d in size and velocity across trials and appeared either (a) in isolat ion, (b) to slide along one side of a single larger stationary object, or (c) to slide between two larger stationary objects. Targets vanish ed without warning, and displacements (i.e., differences between actua l and remembered final position) along the axis of motion and orthogon al axis were measured. Forward displacement (a) decreased with increas es in implied friction, (b) increased with increases in target size fo r descending targets, and (c) decreased with increases in target size for ascending targets. When a larger stationary object was to one side of the target, orthogonal displacement was toward that object; when n o object or objects on both sides were present, orthogonal displacemen t was near zero. Results are consistent with previous findings and spe culation on the effects of representational friction, memory averaging , and target size on memory.