Detection of single letters and letters in words with changing vs unchanging mask characters

With a forced-choice procedure and tachistoscopic displays, accuracy of identification was compared for letters presented alone vs the same letters embedded in words or in nonword letter strings. The advantage for single letters over letters embedded in words or nonwords was found to depend jointly upon characteristics of the pre- and postmasks and change vs no change in mask characters in nontarget locations at the onset of single letter displays.