N250 effects for letter transpositions depend on lexicality: 'casual' or 'causal'?

We examined the electrophysiological correlates of one of the most influential orthographic effects: the transposed-letter-masked priming effect. Transposed-letter nonword-word pairs ('jugde-judge'), as well as transposed-letter word-word pairs ('casual-causal') were included to investigate the influence of prime's lexicality in the transposed-letter effect. The results showed that when compared with the substituted-letter control conditions ('jugde-judge' vs. 'jupte-judge'), transposed-letter primes produced a lower negativity in the N250 component. In contrast, no differences were obtained between the two word-word priming conditions ('casual-causal' vs. 'carnal-causal'). The influence of lexicality in the transposed-letter effect is discussed according to the models of visual word recognition and previous evidence from event-related potentials.