reading and dyslexia Flashcards
the mental representation for comprehension
- input (speech)
- activate existing mental representations of sound
–> then link to meaning - output (comprehension)
the mental representation for comprehension - reading
- input (written word)
- activate existing mental representations of written words
–> then link to meaning - output (comprehension)
the building blocks we need for comprehension
- speech input
- form (phonology)
- syntax & morphology
- semantics
the building blocks we need for written word comprehension
- written word input
- form (phonology) & form (orthography)
- syntax & morphology
- semantics
form (orthography)
- alphabet
–> graphemes represent phonemes
–> e.g. M.I.N.T = mint - logographic system
–> characters represent words
–> e.g. 薄荷 = mint - Korean language
–> alphabetic language that looks like a logographic system
–> letters represent words but are grouped like characters
–> e.g. ㅂㅏㄱ ㅎㅏ-> 박하 = mint
do we need phonology (form) when reading?
- hotly debated topic
- most researchers agree that activation of phonological form occurs when reading
- helps with understanding
- occurs at an unconscious level
how many routes are there in terms of how we use the lexicon when comprehending written word?
3
route 1 in written word comprehension
- written word input
- activate letters
- activate phonemes (via letters)
- activate phonological form
- semantics
route 2 in written word comprehension
- written word input
- activate letters
- activate orthographic form
- activate phonological form
- semantics
route 3 in written word comprehension
- written word input
- activate letters
- activate orthographic form
- semantics
DRC: Dual Route Cascaded model of visual word recognition and reading aloud
- excitatory connections
- excitatory + inhibitory connections between different modules
- excitatory connections motivate a process
- inhibitory connections stop a process
how can we measure the DRC?
- adjust the strength of connections
- provide input
- process input through model
- assess output of model against human performance
evaluate the DRC
- computational modelling allows us to ask very specific questions
- test the results
- but rarely able to model all the variables and parameters at work
- not likely to get an absolute answer
- but excellent to test specific questions
how does the DRC work?
- the model assumes that we have two routes to process visual words (reading)
- the ‘non-lexical’ route converts letters into sounds to activate a phonological representation that links to meaning
- the ‘lexical’ route activates an orthographic representation that is linked directly to meaning
what are 2 routes for reading according to the DRC
- lexical route
- non-lexical route
the lexical route of reading
- whole world orthographic representations
- orthographic lexicon
- semantics
- phonological lexicon
–> phonological can activate orthographic and vice versa
non-lexical route
- whole word phonological representations
– whole world orthographic representations - spelling to sound correspondence
- phonological lexicon
spelling-to-sound correspondence
- the relationship between letters and sounds is referred to as ‘grapheme phoneme correspondence’
- maybe key to understanding the problems encountered by people with dyslexia
graphemes & phonemes
- a single grapheme represents a single phoneme
- a grapheme can be made up of a number of letters
–> 2 letter grapheme = ‘th’ in ‘that’
–> 3 letter grapheme = ‘igh’ in ‘night’
–> 4 letter grapheme = ‘ough’ in ‘through’
variety in graphemes
- the same grapheme can be used to represent more than 1 phoneme (i in mint and pint)
- a single phoneme can be represented by more than 1 grapheme (/k/ can be represented by c, k, ck)
- lots of variety in how we represent phonemes via graphemes
- this leads to regular and irregular words
regular vs irregular words
- regular words = follow a set of rules that dictate how a grapheme should be pronounced
- regular pronunciation = aligns with the graphemes most frequent pronunciation
- e.g. mint is regular but pint is irregular
transparent vs opaque language
- you as readers and speakers of English learn regularities implicitly
- orthographies with a lot of regular correspondences = transparent language
- orthography with few regular correspondences - opaque language
- English not considered to be transparent orthography as too many irregular correspondences
shallow vs deep orthography
- transparent = shallow
–> the spelling of each word maps directly on to its pronunciation (e.g. Finnish or Italian) - opaque = deep
–> the spelling of each word does not map directly on to its pronunciation (e.g. English)
mint vs pint
- mint uses the non-lexical route
–> Grapheme-phoneme correspondence relies on regular rules - pint uses the lexical route
–> requires semantics
advantages of the DRC
- allows 2 routes for processing written word
- accounts for orthographic lexicon and phonological lexicon
- accounts for processing of regular and irregular words
- accounts for encountering new or novel words, can be processed via grapheme-phoneme correspondence
the self-teaching hypothesis (Share, 1995)
- children ‘de-code’ words using an understanding of how letters correspond to sounds
- existing phonological representations are accessed (used to access meaning)
- the phonological representation is used to develop an orthographic lexicon of whole words
- in other words they teach themselves to read
learning to read: the self-teaching DRC
- the ‘non-lexical’ route is used to decode words and access an existing phonological representation
- contextual cues are used to select the target word from a list of spoken word candidates
–> many spoken word candidates
–> select the best match from context - exposure to print facilitates the development of an orthographic lexicon
–> lots of reading on a regular basis necessary
how do the reading routes change in skilled readers?
- links between orthographic and phonological lexicon become less strong as reading becomes more skilled
- can just use orthographic lexicon and semantics to gather word meaning
- do not need the long route
–> no longer rely on grapheme-phoneme correspondence
difficulty in the self-teaching hypothesis
- ‘de-coding’ words to access phonological representations is necessary for the development of an orthographic lexicon
- children who struggle to link graphemes with phonemes might not be able to ‘teach themselves to read’
how does DSM 5 define dyslexia?
- difficulties in accuracy or fluency of reading that are not consistent with the person’s chronological age, educational opportunities or intellectual abilities
how does the British dyslexia association define dyslexia?
- dyslexia is a specific learning difficulty that mainly affects the development of literacy and language related skills
- it is characterised by difficulties that may not match up to an individual’s other cognitive abilities
dyslexia definition - Lyon et al. (2003)
- difficulties with accurate and/or fluent word recognition, poor spelling and decoding abilities that are unexpected in relation to other cognitive abilities
dyslexia definition - Ahmed et al., (2012)
- difficulty decoding words results in an inability to sound out new words
- difficulty recognising known words that results in impoverished sight word reading
dyslexia definition - Snowling & colleagues
- problems with phonological processing in understanding how speech sounds correspond to letters
- not a visual problem
- interaction of gene and environment that puts some children more at risk than others
dyslexia - Dr. Ken Pugh
- highlights the importance of fast and efficient decoding in word recognition
- problems in dyslexia based on phonological processing
- linking sounds to visual representations is crucial to reading speed and fluency
how can we identify dyslexia?
- decoding skills
- convert graphemes into phonemes
–> phoneme deletion/substitution task
–> decode pseudowords (non words)
how can we identify dyslexia?
- lexical retrieval
- recognise whole words (i.e. activate representations in an orthographic lexicon)
–> rapid automatic naming tasks (RAN)
–> word identification of regular and irregular words (should be better at regular if dyslexic)
how can we identify dyslexia?
- verbal short term memory
- retain information in STM
–> word span
–> digit span
testing phonological awareness - De Jong & Van der Leij (2003)
- longitudinal study
- phoneme identification
–> say ‘speech’ without the ‘s’
–> say the first sound in the word ‘train’ - graph shows no deficit in kindergarten
- a problem appearing after 1 year of reading instruction that disappears by the end of primary school
testing reading impairment profiles - Nation (2019)
- learning to read data set
- longitudinal
- dyslexic Ps only
–> from a sample of 242 children there were 34 poor decoders - worse performance on measures of phonological awareness at age 7 compared to age 5
testing automatic word processing - De Jong & Van der Leij (2003)
- rapid automatic naming task
–> name images, letters or digits as rapidly as possible
–> graph shows both dyslexic and weak readers are slower to name objects than the control group - then asked to identify words and non-words
–> graph shows dyslexic readers name fewer objects and fewer correct words than the control group
–> does not mean they cannot do the task, but with less fluency or speed
the dyslexic profile
- poor phonological awareness
- problems identifying phonemes
- problems reading non-words - slow lexical retrieval
- rapid automatic naming task shows slow retrieval of letters
- slower word reading for dyslexic group compared to weak & normally developing readers
problems with reading words - the reading routes
- problems reading words could be due to deficits in either the lexical or non-lexical route
- deficits in the Non-lexical route could lead to problems in the lexical route
- deficits in the Non-lexical route would lead to problems reading non-words
the phonological deficit in dyslexia
- initial problems linking phonemes and graphemes results in problems with word reading later in development
- difficulties in reading later in life may be due to phonological deficit when learning to read
–> less robust orthographic lexicon
–> less fluidity in reading
difficulty in de-coding words (the phonological deficit)
- unlikely to be motivated to read
- reading (exposure to print) facilitates the development of an orthographic lexicon
- development of an orthographic lexicon facilitates ‘skilled’ reading
de-coding and orthographic learning
- de-coding skill creates opportunities for self-teaching but does not guarantee that orthographic learning will take place
orthographic learning
- weak phonological processes affect the formation of orthographic representations
- BUT Orthographic learning may be affected independently of phonological processes
- the result could be
an unexpectedly poor speller’ or a subtype of dyslexia called ‘Surface’ Dyslexia
–> typical decoding, reading speed but difficulty in spelling
surface dyslexia
- phonological awareness appears unimpaired
- non-word reading is within a ‘normal’ range
- irregular word reading is impaired (break is read as ‘breek’)
- unable to distinguish between homophones (difficulty telling which of the following is a vegetable been or bean)
- those with surface dyslexia have deficits in their lexical route
Wybrow et al. (2015)
- word reading have highlighted differences in dyslexic profiles
–> surface vs phonological - gathered results for reading a list of irregular words
- demonstrates evidence of a deficit in the lexical route
Peterson et al. (2013)
- large samples of dyslexic populations allow for tests of different profiles to be conducted
- phonological awareness (phoneme deletion)
- Rapid Automatic Naming (images & colours)
- orthographic coding (which of the following is a flower? rose vs rows)
evidence of surface dyslexic subtypes of dyslexia
- Bailey et al (2004)
–> surface dyslexics had difficulty learning a set of irregular words such that they could recognise them and read them out loud - Ziegler et al. (2008)
–> found evidence of a surface dyslexic subtype in children diagnosed with developmental dyslexia compared to a chronological age control group - Naama Friedmann and Max Coltheart (2016)
–> describe a variety of types of developmental dyslexia
two routes for dyslexic subtypes
- surface dyslexia
- deficits to the lexical Route
- no problems reading regular non-words
- problems reading irregular words - phonological dyslexia
- deficits to the non-lexical route
- problems reading non-words
- impairment of non-lexical (GPC) route
review of 5 studies: Sprenger-Charolles & Serniclaes (2003)
- existence of subtypes of dyslexia is debated
- these results are more in line with the hypothesis that a phonological deficit is at the core of developmental dyslexia, than with the idea that a clear dissociation exists between surface and phonological profiles
semantic processing in dyslexics
- children with dyslexia have serious difficulties with forming detailed orthographic representations necessary for fluent reading
- as a compensatory mechanism, they tend to rely more on semantic processing for reading than their typically reading peers
- that is, stronger influences of semantics on word reading can be expected in this group compared with typical readers
Frith & Snowling (1983)
- tested children’s ability to correctly read out loud sentences that ended with a homograph (spelled the same – pronounced differently)
–> e.g. before he made his speech he gave a bow - dyslexic children were more likely to correctly pronounce ‘bow’ than controls
–> rely on semantics and context
Nation & Snowling (1998)
- tested children’s ability to correctly read regular and irregular words in isolation
- and children’s ability to correctly read regular and irregular words after hearing a sentence
- dyslexic readers use context to process both regular and irregular words more than normal readers (i.e. 850ms quicker for regular words in context than in isolation)
- normal readers use context more for irregular compared to regular word reading
semantic priming effects
- a measure of semantic processing that can be used to explore these effects is semantic priming
- if an individual has stronger predictive processing and links between semantic concepts they should have larger semantic priming effects
semantic priming effects in dyslexics
- reaction time (RT) to the word NURSE:
-> related condition = 450ms
–> unrelated condition = 600ms
–> Priming effect = 150ms - dyslexic readers show larger semantic priming effects than normal readers
the triangle model of reading
- consists of orthographic, phonological and semantic systems
- surface dyslexia is associated with deficits in the semantics system
- phonological dyslexia is associated with general phonological impairment