On the time-course of adjacent and non-adjacent transposed-letter priming

We compared effects of adjacent (e.g. atricle-ARTICLE) and non-adjacent (e.g. actirle-ARTICLE) transposed-letter (TL) primes in an event-related potential (ERP) study using the sandwich priming technique. TL priming was measured relative to the standard double-substitution condition. We found significantly stronger priming effects for adjacent transpositions than non-adjacent transpositions (with two intervening letters) in behavioural responses (lexical decision latencies), and the adjacent priming effects emerged earlier in the ERP signal, at around 200-ms post-target onset. Non-adjacent priming effects emerged about 50 ms later and were short-lived, being significant only in the 250- to 300-ms time-window. Adjacent transpositions on the other hand continued to produce priming in the N400 time-window (300- to 500-ms post-target onset). This qualitatively different pattern of priming effects for adjacent and non-adjacent transpositions is discussed in the light of different accounts of letter transpositi...