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

Abstract

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 transposition effects and the utility of drawing a distinction between positional flexibility and positional noise.

Keywords:

• ERPs
• Letter position coding
• Non-adjacent letters
• Sandwich priming
• Transposed-letter effects

This research was supported by the European Research Council advanced grant [grant number 230313] and NIH grants [grant numbers HD25889 and HD043251].

This research was supported by the European Research Council advanced grant [grant number 230313] and NIH grants [grant numbers HD25889 and HD043251].

Notes

¹ Note that the term “position” here refers to within-word letter position, independently of the location of the word with respect to eye fixation.

² The mean voltage value of the epoch starting 100-ms pre-target onset until 600-ms post-target onset was used as a baseline correction because the more conventional use of a pre-target interval resulted in differences between conditions upon target onset. This is probably due to the EEG activity induced by the successive presentation of the target and prime preceding target onset in the sandwich priming technique. It is important to note that the overall pattern of results was not altered by the application of the mean epoch as a baseline correction compared to when pre-target intervals were used.