Identification of letters in words and of single letters with pre- and postknowledge vs. postknowledge of the alternatives

Two experiments were conducted to test how the “word letter phenomenon” (WLP)—a letter is better identified when embedded in a word than when presented alone—is affected by prior knowledge of the alternatives in a forced choice paradigm with tachistoscopic exposures. In Experiment 1, one group of subjects, who were given knowledge of the alternatives after the display, showed the usual WLP. The WLP was eliminated in a second group of subjects who were given knowledge of the alternatives both before and after the display. In Experiment 2, the same subjects were either precued or not precued on alternating trials of each block. It appeared that the WLP suppression with precuing resulted from a decrease in word performance whereas letter performance was unaffected by precuing. It is suggested that precuing exerts a detrimental effect, because, instead of attending to the word as a whole, subjects search for where in the word the forced choice would be plausible.