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[Q:] When would you prefer a SOSSAGE to a SAUSAGE? [A:] At about 100 ms. ERP correlates of orthographic typicality and lexicalityin written word recognition.
Authors:
HAUK, O., ROGERS, T.T., WOOLLAMS, A., PULVERMULLER, F., Watling, L. & PATTERSON, K.
Reference:
Society for Psychophysiological Research, 45th Annual Meeting, Session 6/35
Year of publication:
2005
CBU number:
6172
Abstract:
Visual word recognition is differentially affected by the orthographic typicality (frequency of letter combinations) and the lexicality (words vs. pseudowords) of letter strings. This study used 64-channel ERPs combined with minimum norm source estimation to investigate the processing stages that are modulated by these variables. The stimuli (n=200 letter strings) for a yes/no visual lexical decision task (n=14 subjects) consisted of matched words and pseudowords with either typical orthography (e.g. LACKEY/KACKEY) or atypical orthography (KHAKI/LHAKI). A main effect of typicality at around 100ms (atypical items producing larger amplitudes than typical ones; main source in left inferior temporal cortex) was followed by an interaction of typicality-by-lexicality at 158ms (due to a bigger word/pseudoword difference for typical strings; distributed sources bilaterally including left anterior temporal cortex), succeeded by a main effect of Lexicality at 210ms and 240ms (pseudowords producing more negative amplitudes than words at posterior electrodes; main source in left inferior temporal cortex). The results indicate distinct but interactive processing stages in word recognition, with the typicality-by-lexicality interaction suggesting integration of information from the early form-based system and lexico-semantic processes. This interaction and its source estimate are of particular interest in light of patients with semantic dementia, whose word recognition is abnormally affected by typicality and whose lesions are in anterior temporal cortex.
