Are Transposed-Phoneme Effects Observed When Listening to Sentences?

In the present study, we asked a simple question: Can transposed-phoneme effects, previously found with nonwords presented in isolation, be observed when the transposed-phoneme nonwords are embedded in a sequence of spoken words that, apart from the transposed-phoneme nonwords, formed a correct sentence? The results are clear-cut. We found no evidence for a transposed-phoneme effect during spoken sentence processing either in a nonword detection task (Experiments 1-3) or in a correct/incorrect decision task (Experiment 4), where "correctness" could either concern individual words (i.e., the presence of a nonword in the sequence) or the entire sequence (i.e., a grammatical decision). Hence, the presence of nonwords in spoken sentences was not harder to detect whether they were created by transposing (e.g., /ʃoloka/) or substituting (e.g., /ʃoropa/) two consonants in the corresponding base-words (e.g., /ʃokola/ chocolat "chocolate"). In contrast, a robust transposed-letter effect was observed during sentence reading (Experiment 5), using the same word/nonword sequences and the same correct/incorrect decision task as in Experiment 4. We discuss the possibility that the greater seriality imposed by spoken sentences in the processing of spoken words leads to a more precise encoding of phoneme order, thus cancelling the transposed-phoneme effect. Sentence reading, on the other hand, would involve more parallel processing, hence the robust transposed-letter effect found with written sentences.