title: The word-length effect in reading: a review.
abstract: The finding that visual processing of a word correlates with the number of its letters has an extensive history. In healthy subjects, a variety of methods, including perceptual thresholds, naming and lexical decision times, and ocular motor parameters, show modest effects that interact with high-order effects like frequency. Whether this indicates serial processing of letters under some conditions or indexes low-level visual factors related to word length is unclear. Word-length effects are larger in pure alexia, where they probably reflect a serial letter-by-letter strategy, due to failure of lexical whole-word processing and variable dysfunction in letter encoding. In pure alexia, the word-length effect is systematically related to mean naming latency, with the word-length effect becoming proportionally greater as naming latency becomes more delayed in severe cases. Other conditions may also generate enhanced word-length effects. This occurs in right hemianopia: Computer simulations suggest a criterion of 160 ms/letter to distinguish hemianopic dyslexia from pure alexia. Normal reading development is accompanied by a decrease in word-length effects, whereas persistently elevated word-length effects are characteristic of developmental dyslexia. Little is known about word-length effects in other reading disorders. We conclude that the word-length effect captures the efficiency of the perceptual reading process in development, normal reading, and a number of reading disorders, even if its mechanistic implications are not always clear.
authors.affiliation: a Departments of Medicine (Neurology) , Ophthalmology and Visual Sciences, University of British Columbia , Vancouver , BC , Canada.
authors.forename: Jason J S
authors.initials: JJ
authors.lastname: Barton
authors.forename: Hashim M
authors.initials: HM
authors.lastname: Hanif
authors.forename: Laura
authors.initials: L
authors.lastname: Eklinder Björnström
authors.forename: Charlotte
authors.initials: C
authors.lastname: Hills
mesh_terms: D020237:Alexia, Pure / Q000503:physiopathology*; D032882:Comprehension; D004192:Discrimination, Psychological; D004410:Dyslexia / Q000503:physiopathology*; D006423:Hemianopsia / Q000503:physiopathology*; D006801:Humans; D007802:Language; D010364:Pattern Recognition, Visual; D010775:Photic Stimulation; D011930:Reaction Time; D014825:Vocabulary
keywords: Alexia; Confusability; Hemianopia; Object recognition; Visual word