Lexical factors in the word-superiority effect.
In the Reicher-Wheeler paradigm, fluent readers can identify letters better when they appear in a word than when they appear in either a pronounceable pseudoword (a lexicality effect) or a single letter (a word-letter effect). It was predicted that if both of these effects involve a lexical factor, then adult acquired dyslexic subjects whose deficit prevents access to visual word form should show disruptions of the normal effects on the Reicher-Wheeler task. The results were that dyslexic subjects as well as matched control subjects showed a lexicality effect; however, while the control subjects showed a normal word-letter effect, the dyslexic subjects showed a reverse letter-superiority effect. Both effects, however, showed a systematic variation: As performance on lexical decision improved, the subjects' performance on words in the Reicher-Wheeler task was better than that for all the other conditions. These subject correlations were replicated by using data from a second lexical decision experiment, which utilized the same words and pseudowords that were used in the Reicher-Wheeler task. In addition, an item analysis showed that the words that the subjects had discriminated correctly in lexical decision showed a significant advantage over those that they had not, as well as an improvement relative to the other 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 the manifestation of other competing factors.
Hildebrandt
N
N
Neuropsychology Lab, Massachusetts General Hospital, Boston 02114.
Caplan
D
D
Sokol
S
S
Torreano
L
L
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001288:Attention; D004193:Discrimination Learning; D004411:Dyslexia, Acquired / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009483:Neuropsychological Tests; D010153:Paired-Associate Learning; D010364:Pattern Recognition, Visual; D010700:Phonetics; D011930:Reaction Time; D011932:Reading; D012660:Semantics; D014706:Verbal Learning