Transposed Letter Effects in Prefixed Words: Implications for Morphological Decomposition.

A crucial issue in word encoding is whether morphemes are involved in early stages. One paradigm that tests for this employs the transposed letter (TL) effect - the difference in the times to process a word (misfile) when it is preceded by a TL prime (mifsile) and when it is preceded by a substitute letter (SL) prime (mintile) - and examines whether the TL effect is smaller when the two adjacent letters cross a morpheme boundary. The evidence from prior studies is not consistent. Experiments 1 and 2 employed a parafoveal preview paradigm in which the transposed letters either crossed the prefix-stem boundary or did not, and found a clear TL effect regardless of whether the two letters crossed the morpheme boundary. Experiment 3 replicated this finding employing a masked priming lexical-decision paradigm. It thus appears that morphemes are not involved in early processes in English that are sensitive to letter order. There is some evidence for morphemic modulation of the TL effect in other languages; thus, the properties of the language may modulate when morphemes influence early letter position encoding.