Orthographic neighbourhood & N400

• N400

  • negative component
  • peak latency around 400ms
  • bi-lateral slightly posterior distribution - both hemispheres

  N400 effect (amplitude modulation)

  • (mis)match of word meaning with preceding context
  • semantic priming
• N400: Sensitive to organisation of semantic knowledge? Federmeier & Kutas (1999) - predictions 


  • If N400 sensitive to organization of semantic knowledge = will differ for within-category to between-category violations
  • If not sensitive = same N400 for both kinds of violation
• N400: sensitive to organisation of semantic knowledge? - Federmeier & Hutas 1999


  • Recorded EEG data while participants viewed sentences with semantic violations
  • N400 = sensitive
  • Within-category violations elicited larger N400 amplitudes / responses compared to between-category violations.
• Orthographic neighbourhood - Coltheart, Davelaar, Jonasson & Besner, 1977


  Non-words with low lexical neighbourhood recognised as words more quickly than those from large lexical neighbourhoods

  • inhibitory effect of neighbourhood in non-words
• Orthographic neighbourhood - Andrews, 1989

  Words with large lexical neighbourhood recognised as words more quickly than those from low lexical neighbourhoods

  • Facilitatory effect of neighbourhood in words
• Orthographic neighbourhood - partial activation of all neighbourhood words - Grainger & Jacobs, 1996


  • Lexical decision based upon activation level of individual word

  or

  • Lexical decisions based upon global lexical activity
• Orthographic neighbourhood & N400 - Halcomb, Grainger, O'Rourke 2002 


  • N400 sensitive to semantic aspects of word processing For words and non-words
  • N400 larger when word has more semantic association (Kounios & Holcomb, 1992)
• Orthographic Neighbourhood and the N400 Holcomb, Grainger, & O’Rourke, 2002


  partial activation of orthographic neighbours =

  • Larger semantic activation with larger neighbourhoods
  • Difference in total semantic activation reflected in size of N400
  • Predicts: Larger N400 for larger neighbourhoods - words & non-words