Phonemic similarity effects and prelexical phonology.

Ten experiments were conducted on visually presented Serbo-Croatian words and pseudowords, comprising phonemically similar and dissimilar context-target sequences. There were five main results. First, phonemic similarity effects in both lexical decision and naming are independent of graphemic similarity. Second, phonemic similarity need not facilitate lexical decision; the direction of its effect depends on lexicality, target frequency, and type of similarity (specifically, the position of the phoneme that distinguishes context and target). Third, phonemic similarity expedites the naming of words and pseudowords, and to the same degree. Fourth, phonemic similarity is negated in naming, but not in lexical decision, when the visually presented context and target are stressed differently. Fifth, the phonemic similarity effect occurs even when the context is a masked pseudoword. These results are discussed in terms of a model in which word-processing units are activated routinely by phoneme-processing units, and in which compositionally similar word units, when activated, inhibit one another in proportion to each's familiarity. In this model, the phonemic similarity effect in naming is based on the states of phoneme units, whereas the phonemic similarity effect in lexical decision is based on the states of word units. Overall, the results comport with an account in which phonology is computed prelexically and automatically.