Chapter 13

Question 1

Reading as a learned expert system

Answer 1

Reading and writing is essentially a cultural invention, albeit of great significance

Literacy emerged 5000 years ago, and became universal in Western cultures 100 years ago (much of the world is still illiterate)

Acquiring literacy requires constructing a dedicated neural/cognitive system

This is likely to derive from a core set of other (evolved) abilities such as visual recognition, speech processing, learning and memory

‘Cultural recycling’: Pre-existing functions are recruited to support a cultural invention (interactions in both directions)

Question 2

Visual word recognition

Answer 2

Cognitive mechanisms:
- Again series of processing stages; starting with general visual processes
- Evidence for top-down effects in visual processing

Neural mechanisms
- Visual word form area (VWFA) responds to written words more than consonant strings (or false fonts), irrespective of which part of space they are displayed in

Question 3

Characteristics of visual word form area

Answer 3

• Responds to learned letters (or true fonts) compared to pseudo-letters (or false fonts) of comparable visual complexity.
• Repetition priming suggests that it responds to both upper and lower case letters even when visually dissimilar (e.g. “a” primes “A” more than “e” primes “A”).
• Subliminal presentation of words activates the area, which suggests that it is accessed automatically.
• Electrophysiological data comparing true and false fonts suggests that the region is activated early, at around 150-200 ms after stimulus onset.

Question 4

Problems in visual word recognition - pure alexia

Answer 4

• Often read letter-by-letter, e.g. CAT = “C”, “A”, “T”, “cat!”
• Disruption of parallel processing of letter strings?
• Damage in or near visual word form area
• Many patients don’t have low-level visual problems but still struggle under perceptually demanded conditions (e.g. joined-up script)
• Controversy about whether the deficit reflects visual processes or reading-specific processes
• Pure alexia is example of peripheral dyslexia (Central dyslexia = after VWF)

Question 5

Damage to lexical-semantic route

Answer 5

Acquired surface dyslexia = damage to lexical–semantic route and reliance on grapheme–phoneme conversion
* Able to read non-words
* Frequency X regularity interaction
* Regularization errors (read as if
regular)

Question 6

Damage to grapheme-phoneme conversion

Answer 6

Acquired phonological dyslexia
* Problem with reading non-words
* Often responded with similar
real word instead

Question 7

Damage to both routes

Answer 7

Acquired deep dyslexia
- Problem with reading non-words more than words
- Also real word reading is error prone, with semantic errors (e.g., CAT => ‘dog’)

Question 8

Reading aloud visual words - other routes?

Answer 8

• To account for dyslexic patients that can read irregular words they do not understand.
• Access to phonological lexicon without semantic memory?

Question 9

Developmental dyslexia

Answer 9

Much more common than acquired dyslexia

Definition: problem in reading/spelling, not attributable to missed opportunity, brain injury, or basic sensory deficits

Visual and auditory explanations.
Most dominant: phonological awareness
= ability to segment speech stream into units

Heterogeneity, sometimes clear-cut developmental surface or phonological dyslexia.

Question 10

Spelling and writing

Answer 10

Spelling = selecting and retrieving a letter string; retrieved code may be abstract in that it isn’t tied to one modality of output

Graphemic buffer = short-term memory component; maintains abstract letter identities during output processes

Two outputs: oral spelling & writing

Writing = translating the abstract letter code into a series of motor commands (pen strokes)

Question 11

A dual route of spelling

Answer 11

Acquired surface dysgraphia = damage to lexical–semantic route and reliance on phoneme–grapheme conversion
* Poor with irregularly spelled words
* Makes regularization errors, e.g. spelling “yacht” as YOT
* Able to spell non-words

Acquired phonological dysgraphia = damage to phoneme–grapheme conversion
* Able to spell real words better than non-words

Acquired deep dysgraphia = damage to phoneme–grapheme conversion and semantic memory
* Able to spell real words better than non-words but makes semantic errors in spelling (e.g. CAT  “dog”)

Question 12

Visual lexicon

Answer 12

A store of the structure of known written words

Question 13

Pure alexia

Answer 13

A difficulty in reading words in which reading time increases proportionately to the length of the word.

Question 14

Peripheral dyslexia

Answer 14

Disruption of reading arising up to the level of computation of a visual word form.

Question 15

Central dyslexia

Answer 15

Disruption of reading arising after computation of a visual word form (e.g. in accessing meaning, or translating to speech).

Question 16

Surface dyslexics

Answer 16

Ability to read non-words and regularly spelled words better than irregularly spelled words.

Question 17

Phonological dyslexia

Answer 17

Ability to read real words better than nonwords.

Question 18

Deep dyslexia

Answer 18

Real words are read better than non words and samentic errors are made in reading.

Question 19

Developmental dyslexia

Answer 19

Problems in literacy acquisition that cannot be contributed to lack of opportunity or basic sensory deficits.

Question 20

Phonological awareness

Answer 20

The ability to explicitly segment a speech stream into units such as syllables, rimes and phonemes.

Question 21

Dysgraphias

Answer 21

Difficulties in spelling and writing.

Question 22

Graphemic buffer

Answer 22

A short-term memory component that maintains a string of abstract letter identities while output processes (for writing, typing, etc.) are engaged.