Direct access by spatial position in visual memory: 1. Synopsis of principal findings.

Changes in the internal representation of a visual display during the first second after presentation are among the earliest phases of human cognition where memory mechanisms may be investigated. The effect of array size (2-6 digits) on the latency to name a visually marked element in a brief display increases rapidly with marker delay, revealing such a change in representation. For early markers the effect is negligible, indicating direct access (and spatially-selective attention); for late markers the effect is a linear increase, indicating a failure of selective attention and suggesting search. Two alternatives to direct access (marker makes element visually distinctive; marker automatically attracts visual attention) are rejected, as tactile spatial markers produce similar effects.