Direct Access by Spatial Position in Visual Memory. 2. Visual Location Probes.

This report continues our series on the short-term dynamics of human visual memory. We summarize the history of the problem, discuss some properties that define a representation as being visual, outline a new approach embodied in four experimental procedures, consider some general issues of design and analysis in assessing an array-size effect, and report on findings from a set of experiments using the spatial-probe procedure with a visual marker as probe. The principal phenomenon is an effect of array size 3-6 digit elements on the time to name a visually marked element in a brief visual display that increases rapidly with marker delay, revealing a transformation of the internal representation of the array that is completed within a second. For early markers the effect of array size is negligible, indicating a property of direct access by spatial location. For late markers the effect of array size on mean reaction time is a linear increase. Keywords Reaction-time Psychology Perception Visual Memory.