Do transposed-letter similarity effects occur at a syllable level?

One key issue for any computational model of visual word recognition is the choice of an input coding scheme for assigning letter position. Recent research has shown that transposed-letter similarity effects occur even when the transposed letters are not adjacent (caniso-casino; Perea & Lupker, 2004, JML). In the present study we conducted two single-presentation lexical decision experiments to examine whether transposed-letter effects occur at a syllable level. We tested two types of nonwords: (1) nonwords created by transposing two internal CV syllables (PRIVEMARA; the base word is primavera, the Spanish for spring) and (2) nonwords created by transposing two adjacent bigrams that do not form a syllable (PRIMERAVA). We also created the appropriate orthographic control conditions, in which the critical letters were replaced instead of being switched. Results showed that the transposition of two syllables or two adjacent bigrams produced a quite robust (and similar) transposed-letter effect. Thus, transposed-letter effects seem to occur at an early orthographic, graphemic level, rather than at a syllable level. We examine the implications of the observed results for the input coding schemes in visual word recognition.