Do transposed-letter effects occur across lexeme boundaries?

A masked priming lexical decision experiment was conducted to examine whether or not assignment of letter position in a word can be influenced by lexeme boundaries. The experiment was run in Basque, which is a strongly agglutinating language with a high proportion of inflected and compound words. Nonword primes were created by transposing two nonadjacent letters that crossed or did not cross morphological boundaries. Specifically, we compared morphologically complex prime-target pairs (e.g., arbigide-ARGIBIDE) with orthographic controls (e.g., arkipide-ARGIBIDE; note that ARGIBIDE is a compound of ARGI + BIDE) and noncompound pairs (e.g., ortakila--ORKATILA) with orthographic controls (e.g., orbahila-ORKATILA). Results showed that transposed-letter effects were virtually the same for compound and noncompound words, both when the orthographic control condition was used as a baseline and when the identity condition was used as a baseline. Thus, transposed-letter similarity effects seem to be orthographic in nature. We examine the implications of these results for the models of visual word recognition.