Week 8 Lecture 1

Question 1

What is opaque orthography?

Answer 1

letter clusters that are not pronounced the same.
The same letters in different words are pronounced differently.

Question 2

How long does it take us to recognise a word?

Answer 2

200ms

Question 3

How do we read?

Answer 3

Left to right, we can move back and forth across the page to understand any ambiguity and check any context.

Question 4

How is speech perception different to perception of written words?

Answer 4

In speech we have to wait for parts of the word to be revealed gradually whereas in reading just fixating on words allows us to process it all at once.
In speech we process phoneme by phoneme to form words then sentences. Retrieve meaning and integrate into the context of the sentence.

Question 5

How are words processed? Why spelling does not matter.

Answer 5

Holistically - As long as the first and last letters are in the right place we can understand the word.

Question 6

What is the word superiority effect? 2 examples, what do they show?

Answer 6

The length of words does not effect how long it takes for us to process them. Therefore, letters are not processed one by one.
Visual distortion can affect how we read but our brain uses context and prior understanding to process the words. e.g. CARPET and CAPPET can both be processed as carpet to make a meaningful sentence.

Letter identification has top-down influences from prior word knowledge - the brain stores some sort of words - when this ability is lost you develop word blindness.

Question 7

What is word blindness? Case study
Conclusion of the study

Answer 7

Dejerine 1892
Able to speak and understand language but not read it.
Monsieur C had damage to his left ventral occipital-temporal cortex. (vOTC) as shown in the autopsy by Dejerine.

Dejerine thought the vOTC area was a connection that carried visual information to the language areas of the brain to be decoded.
Others think it might be a store.

Question 8

Experiment that suggested vOTC is a store of words not just a connection.
Citation

Answer 8

Cohen et al., 2003
Some patients had damage to their vOTC others did not.
Those who did developed word blindness as shown by the word length effect - words are processed relative to their length.
The patients who developed word blindness had damage to their left vOTC and could not read visual information.
Therefore, it is a store as the words are effectively forgotten in terms of what they look like.
If it was only a connection, damage to the other areas of the occipital lobe would have also affected the ability to read.

Question 9

How did they show that the VWFA is located in the left brain only? Who?

Answer 9

Cohen et al., 2002.
Showed that visual information is processed laterally.
Showed a word, word-like stimuli and non-word visual stimuli in left/right visual field.
They subtracted brain activations from each other to show that when stimuli are shown in the LVF, they are processed in the right side of the brain.

Then compared word stimuli to non-word visual stimuli. The only difference in activation was in the left vOTC.

Question 10

Continuation of left only vOTC study to look at word like vs words.

Answer 10

Cohen et al., 2003
Words shown in both hemifields activate the VWFA more than consonant strings.

Conclusion
Only the left vOTC seems to be specialised for word processing.

Question 11

Patient case study that the VWFA is on the left.

Answer 11

Cohen 2000.
Patient A.C.
Split brain patients cannot process word stimuli presented in the LVF. The information is sent to the right side of the brain but cannot be sent back to the left vOTC. In split brain patients the corpus callosum is damaged.
When information is presented in the RVF, both the control and patient show activation of the left vOTC.

Question 12

What stimuli does the VWFA respond to?

Answer 12

Price & Devlin 2003
The VWFA also responds to a range of non-visual word stimuli e.g. naming pictures, creating a story around a picture, reading braille.
Reading is quite a recent invention so it is unlikely that the area is developed specifically for reading but instead responds to particular kinds of stimuli that are important for reading.

Question 13

How do reading difficulties e.g. dyslexia develop?

Answer 13

Due to acquired brain damage from injuries, stroke, dementia

Question 14

What is peripheral dyslexia?

Answer 14

Disruption of early visuo-attentional processing (letters and words).
Affects the early stages of reading and is more general - affects attention and visual processing mainly.

Question 15

What is central dyslexia?

Answer 15

Something central to the reading process is damaged e.g. phonological or semantic processing after visual word form processing.

Question 16

Pure alexia

Answer 16

Type of peripheral dyslexia
Maps the left vOTC to visual word form processing.
It is word blindness. Reading is done letter by letter.

Patients have degraded letter representation e.g. do not know that A and a are the same - they only have a visual capacity, very surface level.

Question 17

Give examples of peripheral dyslexia

Answer 17

Pure alexia
Attentional dyslexia
Neglect dyslexia

Question 18

Give examples of central dyslexia

Answer 18

Surface dyslexia
phonological dyslexia
deep dyslexia

Question 19

Attentional dyslexia

Answer 19

Peripheral dyslexia
Patients struggle separating letters/words. Struggle to identify letters within words and words within a sentence.
Often letter migration errors e.g. WIN FED –> FIN FED. They cannot see letters when flanked by other letters. Letters surrounding letters of importance distract from main letter.

Normal brain can amplify information at the centre of the fixation and suppress peripheral info - these patients cannot.

Typically have parietal brain damage (controls attention).

Question 20

Neglect dyslexia

Answer 20

Peripheral dyslexia
Also an attention problem but more lateralised (more left than right side of the brain).
If you damage left parietal lobe it struggles to regulate attention to right hemifield.

Patients substitute letters on the right side of the words

Question 21

Surface dyslexia

Answer 21

Central dyslexia
Can’t pronounce irregular words e.g. pint.
Able to read regular words and non-words (know the rules of regular pronunciation).
The brain has to remember the specific combinations of letters and the sounds they make together (each mapped to a specific sound).

Phonological lexicon (sound store) affected - cannot remember the specific sounds.

This is evidence for having a rule based system where you can map certain letter combinations to sounds.

Question 22

Phonological dyslexia

Answer 22

Central dyslexia
Can’t pronounce non-words.
Phonological lexicon (sound store) is fine.
No prior knowledge of non-words so can’t remember how to pronounce.

They tend to read a nonword as a real word e.g. CHURSE = NURSE.
Show issues with phonological processing e.g. auditory rhyme judgements.

Posterior damage between the parietal and temporal junction. Forget rules.

Question 23

Deep dyslexia

Answer 23

Central dyslexia
Read real words with semantic errors (meaning) e.g. read cat and think dog.
They make grammatical errors e.g. derivational errors e.g. cannot see that beggar is derived from beg.

Frontal anterior part of temporal lobe damage.

Question 24

Describe the dual-route model of reading aloud.

Answer 24

Route 1 - lexico-semantic route. Converts word form into meaning into pronunciation.

Route 2 - Phonological route. Work out the mapping between visual letters and sounds - difficult in English.

Question 25

What is transparent orthography?

Answer 25

Languages where the sounds fully map to the spelling e.g. Spanish.

Question 26

Grapheme vs phoneme

Answer 26

Grapheme - smallest meaningful unit of written language (individual letters or sounds).

Phoneme - smallest meaningful unit of spoken language (individual letters or sounds).