week three

what is the word superiority effect

The tendency for people to recognise a letter more accurately and quickly when it appears within a real word than when it appears alone or in a random string of letters. This suggests that word-level knowledge helps letter recognition.

what are regular words

Words that follow common spelling-to-sound (grapheme-to-phoneme) rules, making pronunciation predictable.

what are irregular words

 Words that do not follow standard spelling-to-sound rules and must be recognised from memory.

what is a grapheme

The smallest unit of written language that represents a sound (phoneme).

what is a phoneme

The smallest unit of sound in a language that can distinguish meaning.

what is a semantic paralexia

A reading error in which a person reads a word as another word that is semantically related (similar in meaning).

what is the first stage of reading process

letters to meaning of words through mental lexicons activating the intended word

• Orthography -> phonology -> semantics

what factors affect word recognition speed

• frequency

• age of acquisition effect

• orthography

• morphology

• semantics

how does frequency affect word recognition speed

• High frequency words recognised fast then low

• More frequent -> faster/more accurate

• General information retrieval mechanism

• Less frequent words tend to be less familiar, less meaningful

how does age of acquisition effect (AoA) affect word recognition speed

• Words that are learned at a younger age are recognised faster

how does orthography affect word recognition speed

• Transposed letters - same letters of the words but switched

• Substituted letters - different letters

• Parafoveal processing of letter information leads to a boundary change paradigm

  • Parafoveal processing: processing is complete even before we look at a word

how does morphology affect word recognition speed

• Morphemes: the smallest meaningful unit of a language

  • Can be a word itself or part of a word

  • Made up of roots and affixes (prefixes and suffixes)

• Compound decomposition

• Pseudo-affixes: look like they have an affix

how does semantics affect word recognition speed

• Words that are recognised faster are semantically richer

• More semantic features -> more semantic neighbours -> higher imageability -> more concrete -> easier to bodily interact with

• Degree of emotional valence (positive/negative/neutral) and a degree of arousal (high/low)

what do models of word recognition look at

1. How words are searched in the mental dictionary

   • Word entries are searched one at a time

     • In series

   • Word entries are search all at once

     • In parallel

2. How information flows

   • Strictly one way

     • Letters -> words

   • Interactive

     • Letters <-> words

what are the models of word recognition

1. Foster’s search model

2. Morton’s logogen model

3. R&M interactive activation model

what is Foster’s search model

• Recognise letters -> access unit -> get some initial units -> chooses a 'bin' -> once in a 'bin' entries are searched one by one

• Bins are ordered by frequency

• Several units are possible

• word entries are search one by one - serial

• there is a parallel search phase to decide which bin to search

• simple model

what is Morton’s Logogen model

• sends information about letters to all word detectors (logogens) at once - parallel

• information only feeds forward from letters to words

• each logogen has a threshold value based on factors (eg frequency)

• when activation passes threshold → fire → word recognised

what is the logogen system

• information accumulates from bottom up in one direction

  • features → letters → words

• When enough information has accumulated a threshold is passed and the letter is recognised

• If not enough information accumulates it's not recognised

• High frequency words have lower thresholds for recognition as are recognised faster 

what is the R&M Interactive Activation and Competition model

• Parallel activation of letters and words

• Feedback from words to letters

• High frequency words have higher resting levels of activation

• All words have the same threshold to cross for recognition

what is the Dual Route Model

• Word and letter recognition

• Reading regular words out loud

  1. Regular words: use most predictable pronunciation based on spelling

• Reading irregular words out loud

  1. Irregular words: pronunciation is not predictable based on how the word is spelled

• Reading new words

  • 'nonwords' used in experiments (strings of letters)

what happens if there is damage to the lexical system

• Leads to difficulty in reading all words but specifically irregular words

  • Reading occurs via Grapheme Phoneme Conversion

• Ability to read non-words will remain normal

• Expected errors - impairment of irregular words 

  • Percent correct - non-word/regular word reading is good

  • Regularisation errors

what are the types of dyslexia

1. Surface dyslexia: an acquired type resulting from a brain injury

2. Phonological dyslexia: acquired from a brain injury

3. Deep dyslexia: semantic paralexia and damage to semantic system

4. Developmental dyslexia: learning difficulty affecting skills involved in accurate and fluent word reading and spelling

what are the features of developmental dyslexia

• Poor reading - slow and inaccurate

• Poor spelling

• Poor comprehension

  • A secondary consequence - due to not being able to read fluently

  • Reading reducing experience

• A continuum

• Not related to intelligence

• Has common co-occurring conditions - ADHD, dyscalculia

• 10% world-wide, occurs in all languages

  • Can be more apparent in languages inconsistent with orthographies (eg English)

what is the aetiology of developmental dyslexia

• Neurobiological origin

• Moderate heritability

• Twice as common in males

• Cause - multifactorial, associated with multiple genes and environmental risk factors

• Children at genetic risk who later become dyslexic look at less books and avoid reading

how can developmental dyslexia be treated

• Intensive instruction in phonics, phoneme awareness, word analysis and reading

• Intervention better than remediation

• Alternative therapies lack evidence on effectiveness

what are the theories of developmental dyslexia

1. phonological deficit theory

2. double deficit theory

3. magnocellular deficit

4. cerebellar deficit

what is the phonological deficit theory

dyslexia stems from poorly specified phonological representations, making it hard to map letters to sounds

• Most widely accepted

• Poor phonological awareness (ability to manipulate sounds)

• Poor verbal short term memory - remembering sequences of sounds or letters

• Slow lexical retrieval - ability to name aloud letters or objects rapidly

• weakness - some children with reading problems show no clear phonological deficit, phonological problems also

  occur without dyslexia. Difficult to explain speed deficits (

what is the double deficit theory

phonological deficits and slow naming speed are seperable sources of reading difficulty, and children with both are most impaired

• Extension of phonological

• 2 deficits

  • Phonological deficit - related to accuracy

  • Naming speed deficit - related to fluency

    • Naming speed measured by Rapid Automatized Naming

    • Used to diagnose children

• weakness - RAN partly indexes phonological access

what is the magnocellular deficit theory

• Dyslexia results from reduced sensitivity in neural pathways of visual system

  • Magnocellular pathway: fast transmission from retina to occipital and parietal brain regions

  • Visual stress

• weakness - struggles to explain the strong phonological findings, no good evidence

what is the cerebellar deficit

• Cerebellum not only for motor skills but also cognitive, including language

• Reduced activation in right cerebellum

  • Temporal processing deficit

  • Poor naming speed, time estimation, balance

• weakness - motor deficits are not found in all dyslexics

what is Rapid Automatised Naming

• predicts later reading beyond phonological awareness, leading to double deficit hypothesis

• digits and letters predict reading more strongly

• RAN involves attention, serial processing, articulation and lexical retrieval

what does Frith suggest are the three stages of reading development

1. logographic stages: instant word recognition on the basis of salient graphic features, words are visual entities (logographs), no phonological awareness

2. alphabetic: letter-sound analysis, attaching sounds to letters and blending individual sounds together in words, does not happen naturally, failure to acquire strategy results in poor reading of nonwords and poor spelling

3. orthographic: development of automatic word recognition from lexical memory, can use morphemes stored in memory, analysing words in orthographic segments faster than phonological analysis (7-9 yo)

what did Frith suggest about developmental dyslexia

• dyslexic children show persistent struggles in developmental delays when learning new strategies, even when exposed to intervention

  • dyslexia is a developmental disorder not a delay

• dyslexia is situated at the second (alphabetic) stage: problems acquiring the alphabetic strategy

can dyslexia show differently in different languages

• occurs in every writing system

• symptoms depend on how regularly spelling maps onto sounds

• languages differ in orthographic depth

what did Juhasz and Rayner discover about reading frequency using eye tracking

1. words that occurred more frequently were read more quickly - frequency predicted all eye-movement measures

2. words rated as more familiar received shorter fixation times

3. word length predicted gaze duration and total fixation duration - longer words received multiple fixations

4. concrete words produced shorter fixation times than abstract words

5. early learned words were processed more quickly than words learnt later