Lecture 3 Flashcards
describe the first stage of reading, visual word recognition
getting letters to the meaning of a word
a small set of symbols in combination makes up an infinite set of words
define mental lexicon
systematic organisation of words in your brain (+_ 60,000 - 70,000)
how does frequency affect word recognition speed?
high frequency words are recognised faster than low frequency words
general information-retrieval mechanism
less frequent words also tend to be less familiar, meaningful, and more nonword-like; if more like non words, more difficult to say “yes, it is a word” -> post-lexical factors
define the age of acquisition effect
words that you learned at a younger age are recognised faster
overlap with frequency, but not completely, e.g. kite
what did RAYNER say about transposed and substituted letters?
substituted letters more disruption than transposed letters
BUT transposed letters still costly compared to identical controls
t and s letter do slow down understanding, especially if the change is at the beginning or, to a lesser extent, the end of a word
what did REY say about transposed and substituted letters?
letter detection: is there an “A” in BOARD / BRASH?
A = grapheme, OA = grapheme
easier to indicate “yes there is an A” in BRASH than BOARD
-> Graphemes are processed as perceptual reading units. To get to the “A” in “BOARD”, you have to break apart the “OA”
define graphemes
letters and letter groups that correspond to one sound (phoneme)
what are morphemes?
the smallest meaningful unit of a language
can be a word itself (e.g., deck) or part of a word (de-brief)
explain roots and affixes in a morpheme
(prefixes and suffixes)
“unreal” has two morphemes “un-“ (prefix) and “real” (root)
“farmhouse” has two morphemes “farm” and “house”
what is compound decomposition?
tests whether compounds are decomposed into their constituents
immediate effects of lexeme (constituent) frequency
later effects of whole-compound frequency
-> immediate decomposition, but also whole word representation
What are pseudo-affixes?
CORNER (pseudo-suffix: CORN + ER)
BROTHEL (no pseudo-suffix, but contains existing word broth)
what occurs during word recognition with pseudo-affixes?
if pseudo-affixes are not distinguished as a unit, then priming comparable for both conditions
if pseudo-affixes are used to divide up words, then greater priming for CORN+ER -> CORN than for BROTHEL -> BROTH
suffixes (and possible suffixes - pseudo-suffixes) are extracted as units early during word recognition
are semantically rich words recognised faster or slower?
faster,
more semantic features; more semantic neighbours higher imageability, more concrete; easier to bodily interact with; degree of emotional valence (positive, negative, neutral: lucky - angry - plain); degree of arousal (high, low: snake -sleep)
how can semantics (supposed to come in only after accessed) affect recognition?
feedback from semantic to orthographic and phonological layer (interactive)?
marker or “flag” associated with orthography?
what is parafoveal processing?
lots of processing is done even before we look at a word
evidence that frequency of next word is extracted within ~100ms of looking at the word before
what is the first model of word recognition?
word entries are searched one at a time (in a series or serially)
word entries are searched all at once (in parallel)
what is the second model of word recognition?
information flows in strictly one way: letters -> words
interactive: letters <-> words
considering information flow, are there feedback connections between letters & words?
letters in words detected better than letters in nonwords
feedback from words to letters
letters in words detected better than letters on their own -> word superiority effect
describe Forster’s search model: a simple serial search
- recognise letters “COW”
- get some initial unit e.g. first letter
this choses a bin (e.g. the letter “C” bin for the word “COW”) - once in a bin, entries are searched one by one (bins are ordered by frequency)
- use master file to get to meaning
describe the parallel model: the Logogen model
send info about letters to all word detectors (logogens) at once
info only feeds forward from letters to words
each logogen has a threshold level based on e.g. frequency
when activation passes threshold -> fire -> word recognised
summarise the Interaction Activation Competition (IAC) model
parallel activation of letters and words
feedback from words to letters
high frequency words have higher resting levels of activation (not lower thresholds - note: difference from logogen mechanism)
all words have the same threshold
describe ASIDE: Nettalk
connectionist neural network from the 1980s
1 input layer, 1 hidden layer, 1 output layer
about 300 “neurons”, interconnected -> 18,000 “synapses”
first random sound generation, with backwards propagation, starts to learn what is good and not (adjusting strength of connections)
does not contain any spelling-to-sound rules
after 1/2 day - can learn 1,000 words
what is the dual-route model?
not just word recognition, but also from letters on a page/screen to speech
reading predictable words out loud
- pronunciation is predictable based on how the word is spelled
e.g. “SAT” “SPEAK” (called regular words)
reading unpredictable words out loud
- pronunciation is not predictable based on how the word is spelled
e.g. “YACHT” “STEAK” (called irregular words)
reading new words
- in experiments we use “nonwords” (nonsense words)
nonwords are letter strings which aren’t real words
two types:
pronounceable (e.g. chotel)
unpronounceable (e.g. rpteeof)
what is neuropsychology?
neuropsychology is the study of patients who have suffered brain damage
how will we expect a patient to respond after damage to the lexical system?
read of words will be difficult
reading of non-words/novel words will be normal
impairments of irregular words are expected
what is the non-lexical route to speech?
GPC
grapheme / phoneme conversion system
converts letters into sounds
what is surface dyslexia?
an “acquired” dyslexia (results from a stroke/brain injury)
what is phonological dyslexia?
another acquired dyslexia resulted from stroke/brain injury
what is deep dyslexia?
possibly a more severe form of phonological dyslexia
difficulties in reading
- nonwords
- function words
- visual errors (e.g. “think” instead of “thing”)
- abstract words (imageability effect)
- and others
what is the defining feature of deep dyslexia?
semantic paralexia
produce words related in meaning:
DUEL > sword, rapier
BIRD > canary
what were the findings of the lexical effects on reading nonwords?
TAVE vs. TAZE
neighbours of TAVE: SAVE, CAVE, DAVE, NAVE
but also HAVE (expectation word)
neighbours of TAZE: HAZE, MAZE, GAZE, DAZE
no expectations in pronunciation
dual route model predicts TAVE = TAZE because
1. both are nonwords -> use GPC
2. GPC is independent -> words should have no influence
HENCE, lexical neighbours influence both pronunciation times and errors for nonwords -> not all nonwords processed in the same way (dual route model)
what were the findings of regularity effects on reading words?
regular consistent words:
“wade” rhyming neighbours: made, jade, fade, bade
regular inconsistent words:
“wade”. rhyming neighbours: pave, gave, cave, save, rave, but also: have
Dual route model predicts WADE = WAVE because: 1. both are words -> use direct route 2. consistency should not influence RTs or errors
BUT regular consistent words named faster & more accurately
hence, not all words processed in the same way
summarise unimpaired data
nonwords seem to be affected by word neighbours (words that look similar) - this should not happen if all words are simply looked up
words seem to be affected by grapheme-phoneme correspondence - this should not happen if all words are simply looked up
the solution to this is the race mode where both routes “race” against each other and the fastest route wins
define developmental dyslexia
dyslexia is a learning difficulty that primarily affects the skills involved in accurate and fluent word reading and spelling
what are the hallmarks of dyslexia?
- poor reading (slow, inaccurate)
- poor spelling
- poor comprehension
- secondary consequence - by product of not being able to read words fluently
- reduced reading experience (bc reading can be exhausting, time consuming)
- continuum
- not related to intelligence or classroom instruction
what are the common co -occurring conditions?
ADHD, dysgraphia, dyscalculia, stuttering?
can dyslexia be found across any language?
yes, in all languages
though can be more apparent in languages with inconsistent orthographies
what is etiology?
- neurobiological origin
- moderate heritability (0.50)
- twice as common in males
- cause = multifactorial, associated with multiple genes and environmental risk factors
- children at genetic risk, who later become dyslexic, look less at books and avoid being read to more even before learning to read
what is the treatment for etiology?
intensive, explicit instructions in phonics, phoneme awareness, word analysis, reading fluency, and reading comprehension
intervention better than remediation
what is the first of four major theories of DD?
phonological deficit theory
what is the phonological deficit theory?
most widely accepted
1. poor phonological awareness (ability to manipulate sounds) e.g. phoneme deletion/substitution, syllable counting
2. poor verbal short-term memory, remembering sequences of sounds or letters
3. slow lexical retrieval, ability to name aloud letters or objects rapidly
what is the second of four major theories of DD?
Double Deficit Theory
extension of first theory
2 deficits: phonological deficit (mainly related to accuracy) and naming - speed deficit (related to fluency)
naming speed measured by RAN (rapid automatised naming)
often used to diagnose reading difficulties in children
what is the third of four major theories of DD?
Magnocellular deficit
what is a magnocellular deficit?
dyslexia results from reduced sensitivity in the neural pathways of the visual system
magnocellular pathway: fast transmission from retina to occipital and parietal brain regions
magnocells 27% smaller in people with dyslexia
visual stress (can result in headaches, eye strain, poor concentration)
what is the fourth and final major theory of DD?
Cerebellar deficit
what is a cerebellar deficit?
cerebellum not only for motor skills but also cognitive skills, including language
people with dyslexia: reduced activation in the right cerebellum -> temporal processing deficit
poor naming speed, poor time estimation, poor balance
summarise this lecture
recognising a simple word is very complex
- effects of frequency, orthography, morphology, semantics (also phonology)
different models of word recognition differ in search and information flow
dual route model of reading can handle data from certain types of dyslexia, but struggles with “unimpaired” data
