Commonalities across synaesthetes
Lance
A quirky psychological phenomenon known as "grapheme-color
synaesthesia"
describes individuals who experience vivid colors whenever they see,
hear, or
think of ordinary letters and digits. A hallmark of synaesthesia is
that
individuals seem to be idiosyncratic in their experiences. That is,
most
synesthaetes will consistently see the same colors accompanied with
specific
graphemes, but few of these experiences appear to be shared with other
synesthetes.
But new research appearing in the April issue of Psychological
Science, a
journal of the Association for Psychological Science, adds to a
growing body of
evidence suggesting that commonalities do indeed exists across
synesthetes. In
their own study of 70 synesthetes, and a reanalysis of 19 more in
previously
published data, psychologists Julia Simner, of the University of
Edinburgh and
Jamie Ward of the University of Sussex have found that synesthetes
share certain
grapheme-color combinations (for example, the letter 'a' is frequently
associated with seeing the color red).
Interestingly, they found that the particular pairings are determined
by how
frequently graphemes and the colour terms are used is used in
language: common
letters (e.g., "a") pair with common colour terms (e.g., 'red') and
uncommon
letters (e.g., 'v') pair with uncommon colour terms (e.g., 'purple').
This shows
that perceptual synaesthetic experiences are influenced by
environmental
learning.
They then made an interesting discovery about all people. Colleagues
had
reported that that the frequency of graphemes influenced the
saturation of the
colour, but Simner and Ward discovered the root of this effect: that
colors we
speak about most often (i.e., those with the highest linguistic
frequency) are
the least saturated (e.g., black, white).
Although these findings may help explain common features of
synaesthesia, the
precise relationship remains unclear, according to the authors.
However, the
current study aligns with past research suggesting "that different
measures of
such associations converge to illustrate a nonarbitrary relationship
for all
people between color names and color space."
Source: Association for Psychological Science
http://www.physorg.com/news128707448.html
Dave Smith
However, Jeffrey Gray argued (in 'Consciousness: creeping up on the
hard problem') that "word-colour synesthesia is based upon an
abnormal, probably genetically determined, projection hard-wired into
the brain".
Dave
Lance
>
> - Show quoted text -
Thanks for the comment - but (forgive me) so what?
Lance
Dave Smith
>
> - Show quoted text -
I have only superficial knowledge of the issue, but there seems to be
a difference of opinion about whether word-colour synesthesia is
affected by learning.
Dave
Lance
OK. However the article posted above does provide some fresh evidence
that synaesthesia is responsive to experience. Perhaps you find it
unconvincing?
Lance
Dave Smith
I didn't grasp some of the argument. In particular, what is the
reasoning here?
Lance
>
> - Show quoted text -
There are books of words ordered according to how frequently they are
used. I think magazines and newspapers are the primary source for
these lists. Similarly - largely as a result of cryptography research,
there are lists of how frequently particularly letters occur (letters
= graphemes). It seems that the colour associations of synaesthetes
with particular letters are not random, for common (high frequency of
use) letters are paired with colours that have words that are more
frequently used. (I know there is research showing that if a language
distinguishes only one colour taht colour will be red; etc. So the
frequency with which colour words are used is almost certainly not
random).
Lance
Dave Smith
What learning conditions in infancy would result in the hearing of
particular uncommon sounds being paired with the experiencing of
particular uncommon colours?
Gray reports various considerations that count against an associative
learning explanation. Synaesthesia runs in families, and is mainly
reported by and found in females. Different colour-word synaesthetes
experience different colours in response to the same sounds, but the
pairings experienced by a particular individual seem to be invariant
throughout her life. When synaesthetes are given the appropriate
auditory stimuli their brains show activity in the area of the brain
associated with colour vision (V4). Attempts to train non-
synaesthetes so that they show similar activity under such conditions
have failed, and attempts to train word-colour synaesthetes to show
similar activity when the stimuli are melodies have failed.
Furthermore, some word-colour synaesthetes experience 'alien' colours
-- for example, green when they hear the word 'red' -- and it isn't
apparent how this could be learnt from normal environmental
conditions.
(Gray discussed synaesthesia at some length, since he thought it
provided evidence against a functionalist account of consciousness,
and against a 'direct', perceptual realist approach.)
Dave
Lance
Just being alive and living in an environment containing a particular
language, I guess.
>
> Gray reports various considerations that count against an associative
> learning explanation. Synaesthesia runs in families, and is mainly
> reported by and found in females. Different colour-word synaesthetes
> experience different colours in response to the same sounds, but the
> pairings experienced by a particular individual seem to be invariant
> throughout her life. When synaesthetes are given the appropriate
> auditory stimuli their brains show activity in the area of the brain
> associated with colour vision (V4). Attempts to train non-
> synaesthetes so that they show similar activity under such conditions
> have failed, and attempts to train word-colour synaesthetes to show
> similar activity when the stimuli are melodies have failed.
> Furthermore, some word-colour synaesthetes experience 'alien' colours
> -- for example, green when they hear the word 'red' -- and it isn't
> apparent how this could be learnt from normal environmental
> conditions.
>
Still, it doesn't seem to be as random as Gray thought.
> (Gray discussed synaesthesia at some length, since he thought it
> provided evidence against a functionalist account of consciousness,
> and against a 'direct', perceptual realist approach.)
>
> Dave
Lance
Dave Smith
> Dave Smith wrote:
>
> > What learning conditions in infancy would result in the hearing of
> > particular uncommon sounds being paired with the experiencing of
> > particular uncommon colours?
>
> Just being alive and living in an environment containing a particular
> language, I guess.
Sorry, but I still don't understand. If such learning was occurring,
it seems to me that uncommon sounds as well as common sounds would
tend to pair with common colours. If an 'a' sound paired with red,
might not a 'v' sound subsequently also pair with red -- the one
pairing wouldn't block the other, would it?
> Still, it doesn't seem to be as random as Gray thought.
Not random, just 'hard-wired'.
Dave
Lance
Hmm. To be 'hard-wired' all languages would have to have the same
ordering for common sounds. But different languages order sounds
differently. The most common letter in English is not the same as the
most common letter in French. Therefore the above research does show
an environmental impact on synaesthesia.
Lance
Dave Smith
>
> - Show quoted text -
Obviously, 'hard-wired' is just a metaphorical expression. It is
applied to brains rather than languages, to indicate that the
structure in question isn't altered much by normal environmental
variation. Of course, no two human brains are sructurally identical.
Gray's claim is that "word-colour synaesthesia is most likely due to
an extra, abnormal, left-lateralised projection from cortical language
systems to the colour-selective region (V4) of the visual system".
People (mostly women) with this abnormal projection are presumably
born that way. The exact pattern of the 'sparking over' that
activates V4 is idiosyncratic. If you are maintaining that the pattern
of sparking over is systematically modified by environmental
conditions, can you specify how this might occur?
Dave
Lance
>
> - Show quoted text -
I'm not maintaining anything. I was simply posting an interesting
paper. So far your objections to this paper amount to saying the
authors are mistaken about their findings because their findings don't
fit with your prejudices. But perhaps there is more than one way in
which things can work? And no, I'm not going to give you my head for
washing by proposing a neuropsych theory in the short space of a reply
to a newsgroup message.
Cheers
Lance
Dave Smith
I haven't criticised the paper. I haven't got access to it and have
only read the abstract which you posted. If you look back over my
comments, you will see I was hoping you would explain more precisely
what the authors claimed and how their findings and conclusions bear
on Gray's account.
Dave
Lance
Dave Smith wrote:
> I haven't criticised the paper. I haven't got access to it and have
> only read the abstract which you posted. If you look back over my
> comments, you will see I was hoping you would explain more precisely
> what the authors claimed and how their findings and conclusions bear
> on Gray's account.
>
> Dave
Sorry, I have also only read the abstract. Too much to do, too little
time.
I thought it sounded interesting.
Lance
Dave Smith
I've glimpsed at a few papers etc that are available on the net and
synaesthesia appears to be a more complex phenomenon than Gray's
account suggested.
Dave