The quiet clam is quite calm: transposed-letter neighborhood effects on eye movements during reading.

In responses time tasks, inhibitory neighborhood effects have been found for word pairs that differ in a transposition of two adjacent letters (e.g., clam/calm). Here, the author describes two eye-tracking experiments conducted to explore transposed-letter (TL) neighborhood effects within the context of normal silent reading. In Experiment 1, sentences contained a target word that either has a TL neighbor (e.g., angel, which has the TL neighbor angle) or does not (e.g., alien). In Experiment 2, the context was manipulated to examine whether semantic constraints attenuate neighborhood effects. Readers took longer to process words that have a TL neighbor than control words but only when either member of the TL pair was likely. Furthermore, this interference effect occurred very late in processing and was not affected by relative word frequency. These interference effects can be explained either by the spreading of activation from the target word to its TL neighbor or by the misidentification of target words for their TL neighbors. Implications for models of orthographic input coding and models of eye-movement control are discussed.