Examining Activation of Lexical and Semantic Representations Without Intention: Evidence from Event-Related Potentials

• Author / Creator

  Anton, Kathryn F.

• Background. According to dual-route models of reading, there are two pathways with which words can be read: an orthographic-lexical pathway used to read familiar regular words and exception (EXC) words, and a grapheme-to-phoneme-conversion (GPC)-sublexical pathway used to read unfamiliar regular words, pseudohomophones (PHs), and nonwords. A recent debate in the reading literature has centered on whether individuals access lexical and semantic representations of letter strings similarly depending on which reading pathway is used. This has been explored via the Stroop paradigm (Stroop, 1935/1992), in which participants name the font colours of words while ignoring what the words say (i.e., reading without intention). We extend previous research by measuring an event-related potential (ERP), the N400, a brain waveform that has been suggested to be involved in the processing of semantic information. Method. The present study explored lexical-semantic access while participants read without intention, using four different types of stimuli that forced readers to use the orthographic-lexical or GPC-sublexical pathways. The experiment examined twenty-four neurologically normal individuals. The amplitude and latency of the N400 were measured using electroencephalography (EEG), and response time and error rate were also measured behaviourally. Results. In the behavioural data, evidence was found of a significant Stroop effect whereby readers were faster to identify the colour of congruent letter strings compared to incongruent letter strings. In the ERP data, the N400 was found as hypothesized. However, contrary to previous findings in the N400 literature, congruent trials exhibited greater negative peak amplitudes then incongruent trials in several different time windows. Conclusions: Both the behavioural data and the finding of an N400 suggest that individuals access lexical and semantic representations without intention regardless of the reading pathway being used. As literacy and the ability to read play a large role in Western society, the results of the current study have important implications as they provide new information on how orthographic-lexical and GPC-sublexical reading processes operate in skilled readers, with possible ramifications for individuals with reading impairments. Thus, the results have theoretical implications not only for cognitive models of reading, but also for improving our understanding of how to help people with developmental and acquired reading disorders.

• Subjects / Keywords

  • N400
  • Reading
  • Lexical
  • Sublexical
  • Stroop
  • Electroencephalography

• Graduation date

  Spring 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R31V5BQ83

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.