[PS-1.14] Length Effect in English Participants with Developmental Dyslexia

Provazza, S. 1 , Roberts, D. 2 , Giofre, D. . 3 & Adams, A. 1

1 Liverpool John Moores University, Liverpool, UK
2 Centre for Cognitive Neuroscience, Brunel University, London, UK
3 Department of Educational Sciences, University of Genova, Italy

Word length effect (WLE) is defined as an increment of the time taken to read as a function of word length. WLE predominantly have been investigated in transparent orthographies where reading impairment is characterized as slow and effortful. Recent literature suggests that WLEs might also be present in opaque orthographies (e.g., English), normally characterized by errors in accuracy due to the inconsistency of these languages. In the present study a sample of 18 adult participants with developmental dyslexia were compared to a matched sample of typical developing readers with the purpose to investigate whether the WLE is a critical aspect in developmental dyslexia even in English. We expected that the developmental dyslexia group would present with marked length effects, in both words and nonwords, compared to the typical developing readers group. Results confirmed our prediction, showing that the developmental dyslexia group presented with WLE. This effect was particularly strong in low frequency words and in nonwords as observed in reading speed. These findings have important theoretical implications for current understanding of developmental dyslexia. In particular, we demonstrated that the WLE could be found even in opaque orthographies.