Dual route

• Dual route theory - Coltheart 1978, 1993, 2001 -

  • assembled route evidence - Van Orden 1987
  • both routes available - which use?
  • determine if target word belonged to given category - some homophones
  • results showed processing homophones = more difficult, particularly for low-frequency words
  • = assembled route used for less familiar words = support existence of multiple reading pathways
• Dual route theory - Coltheart 1978, 1993, 2001 -

  Dual route evidence

  • Homophone effect occurs mainly in low frequency words (Jared & Seidenburg, 1991)
  • found homophone effect - similar -sounding words cause difficulty in word recognition - mainly low-frequency words
  • Low-frequency = processed through assembled route
  • high-frequency words primarily use direct route
• Dual route evidence - Jared & Seidenburg 1991 - suggests

  • low-frequency words with regular spelling-to-sound rules recognized faster irregular patterns
  • = suggests word recognition involves competition between routes -
  • direct route typically prevailing for high-frequency words
  • assembled route for low
• Dual route model - Coltheart 2001 


  • bulk of recognition takes direct route (quickly accessing stored information about familiar words) - weak phonological theory
  • rule based translation - slow, activates wrong phonology for irregular words
• Dual route model - Ferrand & Grainger 1994

  • evidence masked phonological & orthographic priming
  • higher facillitation for orthographic priming with small exposure (20 msec)
  • same at 30
  • significantly higher facillitation for phonological priming at larger exposure (60)
• Dual route model - Ferrand & Grainger 1994 - suggests

  • duration of exposure to phonological & orthographic primes influences facilitation effects on processing
  • visual representation of word forms may play crucial role in early stages of word recognition
  • highlights importance of phonological representations in later stages of word recognition
  • phonological processing may require more time for effective integration into cognitive processes
• Dual route model - Ferrand & Grainger 1994 - dual-lexicon interactive activation model - p1


  
  

  • Dual-Lexicon Model - 2 separate mental lexicons for written & spoken word processing
  • Interactive Activation - Bidirectional activation spread between different processing levels
• Dual route model - Ferrand & Grainger 1994 - dual-lexicon interactive activation model - p2


  • Sublexical Units: Small language processing units; orthographic units activated by visual input, phonological units by auditory input.
  • Mutual Facilitation: Activation of orthographic units facillitates phonological units, and vice versa
• Dual route model - Ferrand & Grainger 1994 - dual-lexicon interactive activation model - p3 


  • Lexicons: Separate repositories of word representations - orthographic and phonological
  • Connections: Inhibitory connections within each lexicon, inhibiting competing units; excitatory connections between orthographic and phonological representations of same word
• dual route theories & dyslexia - Dyslexia or Specific Reading Disability

  
  

  
  

  • No obvious cause for lack of reading mastery
  • Not general intellectual impairment, poor vision, lack of opportunity or motivation
  • 4% of population diagnosed with developmental dyslexia

  Common view that dyslexia due to visual processing problems

  • Information “turned around” – seeing or producing reversed letters
  • Not a good cue for dyslexia
• Dual route theories & dyslexia - what can dual route theories tell us about dyslexia

  • 2 primary kind - some mixed

  Phonological - 60%

  • Trouble with assembled route
  • Normal reading of high-frequency words
  • Very poor on low-frequency words
• Dual route theories & dyslexia - Case study (Snowling et al., 1994)

  • Adolescent boy
  • Normal for high frequency words
  • Much worse for lower frequency words
  • Treatment: intensive training in spelling -to- sound rules
• Dual route theories & dyslexia - Surface

  • 40%
  • Sound out all words laboriously – as beginning readers
  • Problems in visual perception or memory prevents bottom-up visual processing of characters