Word recognition Flashcards
What is needed first in order to be able to recognise words?
Alphanumeric recognition (ability to recognise letters)
What is template matching? Is it bottom-up or top-down processing?
The stimulus is matched to a template in long-term memory - bottom-up.
What is feature analysis?
Features are analysed through cortical cell ‘filters’ which measure size, orientation, shape etc and matched to known templates.
What is the pandemonium model by Selfridge (1959)?
There are four stages in cortical processing - split into ‘demons’.
1: Image demons detect the stimulus
2: Feature demons respond to an element of the stimulus (orientation, colour etc)
3: Cognitive demons react to the input and match the shapes by comparing templates and choosing which is most similar
4: Decision demon makes the final decision using input from cognitive demons
Which areas of the visual pathway relate to each stage of the pandemonium model?
Image = retina
Feature = V1
Cognitive = V2/IT
Decision = ?
What is structural modelling and why does it result in easier recognition?
Description of an object (e.g. describing how a letter looks), becomes easier bc px is able to imagine the shape
What is the word superiority effect?
Letters are identified faster if they are in a familiar word or combination, possibly due to language rules/ redundant letters
What are the reasons for the word superiority effect?
Pronounceability differences
Frequency
Meaningfulness
Orthographic regularity
Neighbourhood density
What are pronounceability differences?
Non-words are harder to remember bc they aren’t recognised and don’t form memorable rounds
What is frequency?
Real words are seen more often so are more easily remembered
What is meaningfulness?
Real words have semantic meaning so are more easily remembered
What is orthographic regularity?
Real words follow spelling conventions so are more easily recognised/remembered
What is neighbourhood density?
Real words are normally similar to others
Where is the Visual Word Form Area (VWFA) and what does it do?
Left fusiform gyrus
Perceives words
Are words processed top-down or bottom-up?
Top-down
What helps us to process words quickly?
Familiar letter, word and sentence combinations - allows for prediction so we don’t have to work as hard to understand it.
Why can we still understand misspelt words?
We make guesses based on context around the words/letters so sometimes misspellings are missed bc we’re not actually reading every single letter/word
What is the missing letter effect?
We skip over function words like ‘the’ and ‘and’ - they are processed quickly to help us understand sentence structure
Does word spacing affect how easy it is to read sentences?
Yes - but easier to understand a sentence with no spacing than a combination of random words with no spacing
What is alexia?
Complete inability to read words as a whole due to brain damage - may have to read one letter at a time. Might also struggle with number and face recognition
What is bilateral projection?
How is a centrally fixated word processed?
There is a 2-3 degree overlap of the hemifields at the fovea
This means that a centrally fixated word is processed by both brain hemispheres, no crossing at the corpus callosum required (so processing is faster)
What’s the evidence for bilateral projection?
Macular sparing - suggests healthy RGCs from one side still able to process vision when the other side is damaged
RGCs present on both sides of midline in monkeys
What is the split fovea?
How is a centrally fixated word processed?
There is no overlap in the fovea, it’s split centrally
A centrally fixated word is processed half and half by each side of the brain and must be combined via the corpus callosum
What’s the evidence for split fovea?
Macular sparing isn’t present in all hemianopias
Px’s with bisected corpus callosum find words easier to read if they are fixated to one side or the other (so one side of fovea/brain is processing it)
