Rapid Communication

Visual Words Differ from Nonwords: Electrophysiological Correlates of Implicit Processing for Bigram Familiarity

[Speaker] Kasai, Tetsuko:1
[Co-author] Uno, Tomoki:2, Urushihara, Ayaka:2, Makinae, Shiika:2
1:Hokkaido University (Japan), 2:Graduate School of Education, Hokkaido University (Japan)

Fluent reading requires implicit transformation of visually-grouped letters into phonological sequences. Previous studies have shown that scalp-recorded left-lateralized N170 of event-related potential (ERP) is associated with such a process, and its enhancement was based on letters/nonletters, rather than words/nonwords, during nonlexical tasks. This fact is contradictory to previous behavioral studies that suggested visual words as perceptual units. The present study examined N170 in response to words and nonwords written by Hiragana, Katakana, and mix of them, which consisted of two letters, while previous ERP studies generally used more than 4 letters. Hiragana words were orthographically most valid in this study. The stimuli were rapidly presented in random order and the task was to detect infrequent blue letters. We observed that left-lateralized N170 over posterior sites was enhanced only for Hiragana words.
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