Gradients versus dichotomies: How strength of semantic context influences event-related potentials and lexical decision times

2013 ◽  
Author(s):  
Barbara J. Luka ◽  
Cyma Van Petten
Keyword(s):  
Lexical Decision ◽  
Event Related Potentials ◽  
Semantic Context ◽  
Related Potentials ◽  
Decision Times

scholarly journals Are Vowels and Consonants Processed Differently? Event-related Potential Evidence with a Delayed Letter Paradigm

2009 ◽  
Vol 21 (2) ◽  
pp. 275-288 ◽  
Author(s):  
Manuel Carreiras ◽  
Margaret Gillon-Dowens ◽  
Marta Vergara ◽  
Manuel Perea
Keyword(s):  
Word Recognition ◽  
Lexical Decision ◽  
Response Times ◽  
Event Related Potentials ◽  
Simultaneous Presentation ◽  
Event Related Potential ◽  
Baseline Condition ◽  
Decision Task ◽  
Related Potentials ◽  
Processing Event

To investigate the neural bases of consonant and vowel processing, event-related potentials (ERPs) were recorded while participants read words and pseudowords in a lexical decision task. The stimuli were displayed in three different conditions: (i) simultaneous presentation of all letters (baseline condition); (ii) presentation of all letters, except that two internal consonants were delayed for 50 msec (consonants-delayed condition); and (iii) presentation of all letters, except that two internal vowels were delayed for 50 msec (vowels-delayed condition). The behavioral results showed that, for words, response times in the consonants-delayed condition were longer than in the vowels-delayed condition, which, in turn, were longer than in the baseline condition. The ERPs showed that, starting as early as 150 msec, words in the consonants-delayed condition produced a larger negativity than words in vowels-delayed condition. In addition, there were peak latency differences and amplitude differences in the P150, N250, P325, and N400 components between the baseline and the two letter-delayed conditions. We examine the implications of these findings for models of visual-word recognition and reading.

The Speed of Orthographic Processing during Lexical Decision: Electrophysiological Evidence for Independent Coding of Letter Identity and Letter Position in Visual Word Recognition

2008 ◽  
Vol 20 (7) ◽  
pp. 1283-1299 ◽  
Author(s):  
Marina Mariol ◽  
Corentin Jacques ◽  
Marie-Anne Schelstraete ◽  
Bruno Rossion
Keyword(s):  
Lexical Decision ◽  
Time Course ◽  
Event Related Potentials ◽  
Letter Position ◽  
Decision Task ◽  
Letter Identity ◽  
Two Factors ◽  
Related Potentials ◽  
Open Question ◽  
Double Letters

Adults can decide rapidly if a string of letters is a word or not. However, the exact time course of this discrimination is still an open question. Here we sought to track the time course of this discrimination and to determine how orthographic information—letter position and letter identity—is computed during reading. We used a go/no-go lexical decision task while recording event-related potentials (ERPs). Subjects were presented with single words (go trials) and pseudowords (no-go trials), which varied in orthographic conformation, presenting either a double consonant frequently doubled (i.e., “ss”) or never doubled (i.e., “zz”) (identity factor); and a position of the double consonant was which either legal or illegal (position factor), in a 2 × 2 factorial design. Words and pseudowords clearly differed as early as 230 msec. At this latency, ERP waveforms were modulated both by the identity and by the position of letters: The fronto-central no-go N2 was the smallest in amplitude and peaked the earliest to pseudowords presenting both an illegal double-letter position and an identity never encountered. At this stage, the two factors showed additive effects, suggesting an independent coding. The factors of identity and position of double letters interacted much later in the process, at the P3 level, around 300–400 msec on frontal and central sites, in line with the lexical decision data obtained in the behavioral study. Overall, these results show that the speed of lexical decision may depend on orthographic information coded independently by the identity and position of letters in a word.

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