W10 numeracy in brain Flashcards
(19 cards)
what is a number?
is it a symbol, unit of measurement
- quantity, code or magnitude
meaning is abstract eg 3 three, III
study number ability through:
relative = compare to something - ‘which has more?’
absolute = its value, ‘are there 8?’
symbolic vs non-symbolic = 3 or 3 dots
-**absolute judgement subitizing **
relative judgements of array size depend on:
-
size
- 10red:5blue easier than 20:10 -
distance
- difference in set size 6:5 harder than 7:5.
what is subitising?
= parallel processing, innate, recognise numbers up to 3/4 without counting
- whereas 4+ more error prone, serial processing, approximating
interaction of symbolic vs non-symbolic
distance and size effect
**large font large number = faster judgement **
distance - distance between numbers 5vs4 slower than 5vs3
size = size of numbers themselves 5vs3 slower than 4vs2
physical size influences numbe
number size influences psysical judgement
is a sense of number innate?
Yes
- common underlying mechanisms in
cultural inventions
- subitizing range general ability across cultures
- tribes different answers for number representation (1, 2, some,many)
- babies habituate to same number, dishabituate new
Ability = biological process
neurons
- neurons code magnitude
they habituate, new response reamplifies them
multi-sensory coding
- respond to sequential (eg dots)
- sounds - beep beep =2
- monkeys PFC visuospatial
humans babies frontal to parietal when learning math
Brain for number meaning: intraparietal sulcus (IPS) region
priming=
- IPS is more active in calculation than reading numbers
- sensitive to priming (one number influences processing of another)
Spatial representation:
- separate brain region for visual recognition of numbers
- IPS - bilaterally activated
- read or spoken number = left hemisphere
- VWFA bilateral
Left and right brain
dyscalculia
- dyscalculia shows left, but sometimes bilateral
- left deals with exact quantities
- right = approximation
split-brain patient:
- left visual field to right hemisphere 46% error
- right visual to left hemisphere less errors
split-brain patient = info goes to one hemisphere
Models of number processing
SNARC = spatial numerical association of response codes
- snarc effect = faster response by left hand to small numbers, right hand to large numbers
Models of numerical cognition
2 of them
- McCloskey model
- Dehaene’s triple code model
McCloskey model is
- everything goes through abstract internal representation
- number size represented as base-10 (10s,100s)
- separate routine for arithemtical operations
- abstract representations for all calculations
- transcoding is semantically
2 Dehaene’s model
- cognitive, neuroanatomical
- number size represented in logarithmical form
- no separate routine for arithmetic
- some calculations independent of number semantics
- doesnt need to be semantic
Transcoding =
translating one type of symbol to another
eg 5 to FIVE
how is number encoded?
- base-10 (10s,100s)
- log-linear (1 to infinity)
mcclocksley is base-10
dehaene assumes ‘mental number line’
DAKIN’s MODEL
visual number perception
- we estimate large numbers
larger patches of dots look more dense and numerous - we encode density
larger circle of dots looks like more than smaller but is same
Dakin model - fine detail processes number of items
WE USE DENSITY FOR LARGER AMOUNTS
SUBITISING WE SENSE NUMBER FOR SMALLER
visual cues interact, 2d vs 3d
symmetry
- density bias - bigger things look more dense
- REDUNDANCY i symmetical patterns appear less numerous, we only attend to HALF
- process symmetry then number
add dots to make it appear same
