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Word Recognition and Reading READING ALOUD Alphabetic Writing Systems ! Individual
phonemes
(smallest unit of
sound) are
represented by
graphemes
! Graphemes: Letter
to letter cluster that
correspond to a
single phoneme –
according to
Coltheart et al 2001
e.g. b, ee, sh, ing (as
in sigh), but not pl,
cr, st
Orthographic Depth Refers to the consistency of mapping, how predicable the spelling to sound or letter to phoneme mapping is ! English is considered to be deep/opaque compared
languages like Italian, which are shallow/transparent
Deep/Opaque Orthography ! Some spelling-­‐to-­‐sound mappings are
ambiguous/inconsistent
! OUGH
• THOUGH
• COUGH
• TOUGH
Some words have ‘irregular’ mapping (odd one out) • PINT – should rhyme with MINT (and hint, dint etc.)
Shallow/transparent Orthography ! Mapping from grapheme to phoneme is one-­‐to-­‐one
Reading words vs. Pseudowords (non-­‐words) ! PINT (irregular word) vs. JINK
(pseudoword)
• Most skilled readers can read both
irregular words and pseudowords (letter
strings that could be a word) correctly
! JINK can be read by means of application of
spelling-­‐to-­‐sound mapping rules
! PINT is a word, but it violates the ‘rule’
about mapping grapheme to phoneme
• PINT is an irregular word
• Regular neighbours: hint, lint, mint, dint
• TO pronounce PINT correctly, we must
have stored pronunciation of PINT
(lexicon = mental dictionary)
Dyslexia’s ! Impaired reading abilities
! Acquired dyslexia: Due to brain
damage (e.g. stroke) previous literate
individuals lose their ability to read
! Developmental dyslexia:
Individuals (children and adults)
who always struggled with reading
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Dual-­‐Route Cascaded Model ! This model accounts for reading aloud and
for silent reading
! There are two main routes between the
printed word and speech both starting with
orthographic analysis (used for identifying
and grouping letters in printed words).
! Key assumptions:
• Individuals use both the non-­‐lexical
(Route 1) and the lexical (Route 2 and
3) paths when reading aloud
• Naming visually-­‐presented words
primarily depends on the lexical route
(operates faster)
• Activation at one level cascades on to the next before processing at the first level is complete
! The main idea is that at least 2 different
ways of generating pronunciation. One is
looking it up in your lexical and the other is
by applying the grapheme phoneme
mapping rule
Acquired Dyslexia Reading could be impaired in different ways: variety of dyslexia’s
Surface dyslexia: intact non-­‐word reading; poor at reading irregular words e.g. PINT, PLAID
Phonological dyslexia: Intact word reading; poor at reading non-­‐words e.g. JINK
Deep Dyslexia: Like phonological dyslexia plus semantic errors (e.g. read TULIP as ROSE
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Word Recognition and Reading Route 1 (non-­‐lexical route): Grapheme-­‐
Phoneme Conversion ! Mapping spelling (graphemes) onto sound
(phonemes)
! Surface dyslexia: Patient KT
• 100% non-­‐word reading accuracy
• 81% regular word reading accuracy e.g.
cat, mint
• 41% irregular word accuracy e.g. Yacht,
pint, plaid
" Most mispronunciations were due to
regularization (e.g. reading pint to
rhyme with mint)
! Woollams, Lambon-­‐Ralph, Plaut & Patterson
2007
• Strong association between impaired
semantic knowledge and surface
dyslexia in semantic dementia patients:
if semantic knowledge is intact, can read
irregular words.
Route 2 (lexical route): Lexicon + Semantic system ! Representations of familiar words are
stored in an orthographic input lexicon
(sight vocabulary)
! Meaning is activated
! Sound pattern is a generated in the
phonological output lexicon
! Using in Phonological dyslexia:
• Particular problems reading
unfamiliar words and non-­‐words
" Thought to involve difficulty
with grapheme-­‐phoneme
conversion
• Patient WB
" Couldn't produce the sound of
any single letter
Maintained ability to read real
words with 85% accuracy
Route 3 (lexical route): Lexicon Only ! Like route 2 but the semantic
system is bypassed
! Deep Dyslexia
• Particular problems in
reading unfamiliar words
(rate words) and non-­‐words
e.g. JINK, VIB
• Semantic reading errors e.g.
ship read as boat, tulip as rose
• May be caused by damage to
the grapheme-­‐phoneme
conversion and semantic
systems
• Resembles a more served
form of phonological dyslexia
• Recovering deep dyslexics
often become phonological
dyslexics
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Word Recognition and Reading We start at the top Letter feature analysis and what letters they are You have to first know the spelling, you look it up in your lexical e.g. pint is a possible word Then it divides into 3 separate routes Wont’ work for irregular words In this context it means on the way to going from spelling to pronunciation you also retrieved its meaning. Meaning isn’t necessary; all you need do is to map the spelling to sound This connects to pronunciation, so given pint you have stored the information that it is pronounced as pint So it takes each letter or letter clusters (grapheme) and maps that onto sound and then generates the pronunciation that phoneme strings at. You string them together and you told it in the response buffer and then you say it aloud Reading: EYE-­‐MOVEMENT STUDIES Reading and eye movement ! We read at the rate of about 4 words per
second (~250 wpm)
! What happens to our eyes when we read
sequences?
! Saccades: Typically take 25-­‐30msecs and
we tend to move about 7-­‐8 characters.
During a saccade, you ‘see’ nothing at all
! Fixations: usually around 250msecs
! Regressions: Infrequent, right-­‐to-­‐left
movements of about 2-­‐5 characters
! End-­‐of-­‐line sweep: we make a single long
from the end of one line to the
saccade beginning of the next
Eye tracking ! Present sentences or passages on the
screen
! Use eye-­‐trackers to:
• Watch how your eyes move
• Control what you see, and when
! Allows us to get questions such as:
• What happens when we read
sequences?
• How do your eyes move?
• Do we only process where we look?
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