Bigram frequency, number of syllables and morphemes and their effects on lexical decision and word naming.

There has been an increasing volume of evidence supporting the role of the syllable in word processing tasks. Recently it has also been shown that orthographic redundancy, related to the pattern of bigram frequencies, could not explain the syllable number effect on lexical decision times. This was demonstrated on a large sample of words taken from the British Lexicon Project. In this study we extend this research by examining both lexical decision and word naming times taken from the English Lexicon Project. There was a syllable number effect for both tasks in the expected direction, and this effect was independent of the presence of a bigram trough. The research also examined the role of other bigram related variables and the number of morphemes on lexical decision and word naming times. The number of morphemes had a significant effect on both word processing tasks, with words with more morphemes producing faster reaction times and also fewer errors. This pattern was reversed for nonword lexical decision times. The results are discussed in the light of recent developments in models of reading.