Multi sensory and synaesthesia Flashcards
define synaesthesia
where one sensory/cognitive pathway leads to an automatic experience in a second sensory/cognitive pathway - joining of the senses
what types of synaesthesia are there
grapheme colour sound colour broadband and narrowband lexical gustatory mirror touch
define grapheme colour
percieve numbers/letters as different colours
define sound colour
hear a sound and see a colour
define broadband
version of sound colour
collection of tones causes colour
define narrow band
version of sound colour
single tone causes colour
define lexical gustatory
unpleasant sensation ie taste of egg triggered by sound of k phoneme
ward and simner 2003 - irrespective of spelling
define mirror touch
ability to feel others pain
day 2005
synaesthesia often pleasant or neutral so do not realise of difference until much older
ward et al 2006 and grapheme colour and sound colour
found similarities between synaesthesiacs
a tends to be red
o white or black
s yellow
lighter colours tend to have higher pitch
banissy and ward 2007 / banissy et al 2011 and mirror touch
mirror touch linked to increase empathy and better emotional discrimination
is synaesthesia inherited?
baron cohen et al 1996 / galton 1883
- appears to run in families but not definite
- more common in females but can be a reporting bias
-difficult to link to x chromosome as there has found to be disconcordance in monozygotic twins and can skip generations
testing for synaesthesia
can only be tested for validity in terms of response stability over a long period of time
baron cohen et al 1993
stability in idiosyncratic patterns provide credible support
if responses are automatic/preattentive then likely to be credible
palemeri et al 2002 and testing for synaesthesia
single subect with grapheme colour syn
asked to colour match 100 works then test after 2 months
97 % correct compared to 43% control correct of undergrad students after two weeks
3% wrong because called ‘beige’ ‘offwhite’
dixon 200/palmeri 2002 and automatic syn
stroop task for control and syn
control - time decrease when report colour over word
syn - faster when report colour as usually sees colour
palmeri 2002 and preattentive syn
visual search of one letter in group of diff letters
- target and distractors
syn - easier to locate target as diff colour to distractors
BUT - may also be faster because easier to reject the distractors
what are the possible neural mechanisms involved in synaesthesia
may be due to reduces neural pruning - unnecessary connections between diff areas in brain removed during development
grapheme colour due to link between visual cortex and visual word form area
disinhibited feedback/hyperbinding as an explanation for synaesthesia
the inducing stimulus and the synesthetic sensation are coupled by a sensory nexus area, which may be located in the parietal cortex - emphasise areas involved in binding and cross sensory integration
neufeld et al 2012 and hyperbinding
auditory visual syn increased activity in left inferior paretial cortex suggesting diff processing in the integration of info
no increase in acitivity in v4 visual cortex
Define the Mcgurk effect
Conflicting info from visual and auditory pathways
Resolve by manipulating perception of soils to fit vision
Why is visual perception more dominant
Seems more compelling/reliable
Why circumstances does vision often dominate
Ventriloquist- Sound as though coming from puppet because lips are moving
TV sound from characters
Visual capture - draw visual shape and not haptic (how it feels)
Describe shams 2000
Disk flash once but two beeps
Think flash twice
Increased beeps not impact
Must be same time frame
Control accurate - issue with integration
Describe neural fission
Fmri record activity in primary visual cortex
Increase in illusion trials of flash and beep
- way of processing change
Define modality precision
The level of variability in the reliability of a cue
Accuracy and precision of a sense
Define modality appropriateness
Tend to weight the more accurate sense as dominating the right context
Ie visual for spacial info
Auditory for temporal info
