Stimulus Position as an Encoding Variable in Brief Visual Presentations

Abstract

The present experiment investigated position factors in the recall of letters tachistoscopically exposed for 50-msec. durations. Using Sperling's (1960) probe technique, subjects recalled the letters from one of three rows of a stimulus array according to a pre-arranged tone signal. The interval between stimulus offset and tone was either 100 or 400 msec., permitting comparisons between the times when the perceptual trace was strong (100 msec.) and when the trace had weakened (400 msec.). The results indicated the presence of position effects while the perceptual trace persists strongly but not when the perceptual trace is weak. The relationship between encoding processes and iconic imagery was discussed.