Subjects discriminate letters in words better than letters in nonwords
. The sophisticated guessing hypothesis attributes this word advantage
to a guessing strategy. In words, the possible letters at each letter
position are constrained by letters at other positions, whereas lette
rs in nonwords are not restricted in this manner. A critical test of t
his hypothesis is that if subjects are given explicit knowledge of the
letters in nonwords before the trial, the word advantage would disapp
ear. We investigated the effect of preknowledge of the alternatives in
the word-detection effect. In the word-detection effect, subjects dec
ide which of two character strings contains letters and which contains
pseudoletters. In four experiments, subjects were more accurate with
words than with nonwords, and subjects were more accurate when they we
re told the word or nonword before the trial. However, even with forek
nowledge of the alternatives, subjects were more accurate with words t
han with nonwords.