LEXICAL FACTORS IN THE WORD-SUPERIORITY EFFECT

In the Reicher-Wheeler paradigm, fluent readers can identify letters b etter when they appear in a word than when they appear in either a pro nounceable pseudoword (a lexicality effect) or a single letter (a word -letter effect). It was predicted that if both of these effects involv e a lexical factor, then adult acquired dyslexic subjects whose defici t prevents access to visual word form should show disruptions of the n ormal effects on the Reicher-Wheeler task. The results were that dysle xic subjects as well as matched control subjects showed a lexicality e ffect; however, while the control subjects showed a normal word-letter effect, the dyslexic subjects showed a reverse letter-superiority eff ect. Both effects, however, showed a systematic variation: As performa nce on lexical decision improved, the subjects' performance on words i n the Reicher-Wheeler task was better than that for all the other cond itions. These subject correlations were replicated by using data from a second lexical decision experiment, which utilized the same words an d pseudowords that were used in the Reicher-Wheeler task. In addition, an item analysis showed that the words that the subjects had discrimi nated correctly in lexical decision showed a significant advantage ove r those that they had not, as well as an improvement relative to the o ther conditions. These results suggest that there is a lexical factor underlying the lexicality and word-letter effects, and it is proposed that the abnormal letter-superiority effect can be accounted for as th e manifestation of other competing factors.