Effects of word-length and word-frequency in dyslexic people: Evidenced through a progressive demasking word identification task

Abstract

People with dyslexia have difficulties in the phonological/lexical level of analysis, given that dyslexic group showed longer reaction times (RT) to long words and low frequency words compared to age-matched controls in tasks as reading aloud isolated words and lexical decision. The present study compared the performance of dyslexic and non-dyslexic readers in a different experimental paradigm of visual word recognition with speeded identification: progressive demasking task. Also, it examined the word-frequency and word-length effects in Spanish language. The results showed faster RT in word identification for the control group compared to the dyslexic group and a significant effect of frequency in the RT. The effect of word-length was not evident; however, RT were slower for the dyslexic group in the low frequency words and long words. The present study provides the following evidence: 1) progressive demasking task showed the same sensitivity as other tasks of word recognition for factors affecting the early stages of visual word recognition (as frequency effect); 2) the dyslexic group had greater difficulty in identifying words in comparison to the control group, as dyslexic group?s word decoding skills were somewhat below the level of the non-dyslexic comparison group (i.e. increased RT for low frequency words and long words); 3) for both groups, we were able to establish highly reliable word-frequency effects; this is compatible with the view that word-frequency influences a relatively early stage of word processing.