Taft, M. & Nillsen, C.
School of Psychology. University of New South Wales. Sydney, Australia
Lexical decision to a nonword formed through transposition of internal letters (e.g., HPAPY from HAPPY) shows greater interference relative to a non-transposed item (e.g., ORTPY) than does a nonword formed by transposition of initial letters (e.g., AHPPY). If a prefixed word (like UNHAPPY) were recognized solely through its stem, one might expect the positional difference in the transposition effect to be maintained when a prefix is added to the transposed stem (i.e., UNHPAPY > UNAHPPY). However, both show equal interference (relative to UNORTPY). While this might then suggest that prefixed words are accessed through whole-word representations, it is necessary to show that the same thing does not happen when a prefix that is inappropriate to the base stem is added instead (i.e., REHPAPY vs REAHPPY vs REORTPY, where REHAPPY has no lexical representation). Because strong interference is observed even for REAHPPY, it is concluded that the positional difference in the transposition effect arises at a perceptual level and, importantly, that decomposition is obligatory.