How many letters in Bidwell's ghost? An investigation of the upper limits of full report from a brief visual stimulus

Abstract

When a display of 14 letters and digits was illuminated by a bright l-msec flash (not followed by a mask), practiced, dark-adapted subjects were able to report 12.4 of the items. This was their average full report, not an estimate from a partial report. This high level of performance documents the clarity of the long-lasting, positive afterimages originally reported in the last century and termed "the ghost" by S. Bidwell. It is thus possible for a full report of a brief visual display to contain far more than the usual estimate of 3 to 4 letters first reported by Sperling (1960). Several trials were recorded in which subjects were able to report all 14 letters. © 1980 Psychonomic Society, Inc.