synesthesia patricia averill, c. dillon martin hall
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SynesthesiaPatricia Averill, C. Dillon Martin Hall
Presentation Outline
• Description• Definition• Types, common and otherwise• Population prevalence
• Theories• Historical Theories• Neural correlates for Synesthesia
• Evidence for Synesthesia as an ASC• Neuroimaging• “Pop-out” Effects• Further Discussion
Synesthesia Defined
• A neurological condition where an observed stimulus in one sensory modality is involuntarily associated with a particular stimulus in another sensory modality
• For Example:
• 1 2 3 4 5 etc...
• Jan (11 o’clock), Feb (12), etc...
• Robert (apple pie), Jane (orange juice)
Types of Synesthesia
• Grapheme Color
• Letters/Numbers on a page appear to be shaded by or are associated with specific colors
• One of the more common forms
• No consistency for grapheme/color associations across synesthetes
Types of Synesthesia
• Grapheme Color
Types of Synesthesia
• Grapheme Color
• "I was sitting with my family around the dinner table and I don't know why I said it but I said, "The number five is yellow." There was a pause and my father said, "No, it's yellow-ochre." And my mother and brother looked at us like, 'this is a new game, would you share the rules?' I was dumbfounded. So I thought, "Well." At that time in my life I was having trouble deciding whether the number two was green and the number six blue, or the other way around. And I said to my father, "Is the number two green?" and he said, "Yes, definitely. It's green." Then he took a long look at my mother and brother and became very quiet. Thirty years after that, he came to my house and said, "you know, the number four *is* red, and the number zero is white. And," he said, "the number nine is green." I said, "Well, I agree with you about the four and the zero, but nine is definitely not green!"
Types of Synesthesia
• Music Color
• Tones or other aspects of musical notes (key, timbre, etc.) are associated with specific colors
• Less common than G C
• Some consistency across synesthetes, as higher notes appear to be more brightly colored
Types of Synesthesia
• Music Color
Types of Synesthesia
• Music Color
• " The sounds of musical instruments will sometimes make me see certain colors, about a yard in front of me, each color specific and consistent with the particular instrument playing; a piano, for example, produces a sky-blue cloud in front of me, and a tenor saxophone produces an image of electric purple neon lights"
-SD
Types of Synesthesia
• Lexical Gustatory
• Words and names are associated with a taste or combinations of tastes
• Rare
• Rhyming and syntactic associations common enough to be occasionally predictable (e.g. Tony Macaroni, or Blue Inky flavor)
Types of Synesthesia
• Lexical Gustatory
Absolute -TangerinesGallery -White ChocolateRegister -Pork Pie FillingAcademy -Thin Chocolate BarRent -CabbageAccept -Egg Yolk, HardRequire -Milk, CondensedAcid -Acid DropsGate -Bacon, ColdReservations -Mars BarAcquire -Milk, CondensedGillian -TonguesReserve -Mars Bar Acrobat -Choc. biscuit thick Glad -Potato, SlicedAdams -Tomatoes, TinnedGlasgow - MilkAdmit -SmartiesGlobal -Pear DropsReveal -Meat Jelly, ColdAdrian -Watery, IncompleteGo -Meat LoafReward -Turkish DelightAdventure -Mashed vegetablesGood -CustardRisk -MilkyAdvert -Beef BurgersGordon -DirtRobert -Jam SandwichesGrab -Bacon, ThickRobin -Jam SandwichesAdvice -CarrotsGreat -Grapes
Roger -
Pork Pie Filling
Aeroplane -
Chocolate, Dark
Greed -
Cabbage
Rope -
Bread Crust
Grimsby -
Fruit Gum, Horrible
Ross -
Cornflakes, mlk & sgr
Grip -
Grape Skin
Route -
Pickled Beetroot
Ago -
Meat Loaf
Group -
Grape
Agree -
Cabbage
Guess -
wafer biscuits
Safety -
Toast lightly butterd
?
Prevalence of Synesthesia
• Early Data
• between “1 in 20” and “1 in 20,000”
• Questionable collection methods relying on self-reporting
• Recent Data
• Prevalence of “1 in 23” suggested by random population study
• Simner et al
Prevalence of Synesthesia
• Tends to cluster in families
• Strongly suggests genetic origin
• Likely “X-linked”, as no father-to-son transmission ever recorded
• Slightly more common in women than in men
• 1.1 : 1 ratio, Simner et al
Historical Theories about Synesthesia
• Is it learned?
• once suggested that colored fridge magnets caused a learned association
• doesn’t explain forms other than Grapheme Color
• Doesn’t explain historical accounts before the prevalence of colored fridge magnets
Historical Theories about Synesthesia
• Is it just an overly vivid imagination?
• As with all ASCs, difficult to tell apart from actual subjective experience
• Test- retest reliability
• Synesthetes: 90% over one year
• Non-synesthetes: 30-40%
• Stroop Effect
Two Main Types Of Synesthesia
• Lower Level
• Fusiform Gyrus
• Higher Level
• Angular Gyrus
Lower Level Synesthesia
Higher Level Synesthesia
Low Level Synesthesia: Pop-Out Effects
Low Level Synesthesia: Pop-Out Effects
Other Effects
• Lower the Contrast
• Colorblind Synesthetes
• Roman Numerals (A Concept)
• Higher level synesthetes will see 5 in the same color as the Roman numeral V
• For lower level synesthetes, the Roman numeral will not appear in color
5 and VFor Example:
Fusiform GyrusThe Cross Activation Hypothesis
Angular GyrusConcept & Metaphor
Booba Kiki Experiment
Synesthesia as an Altered State?
• Lack of Pruning (Selectively or Globally)
• Artists and Poets
• Greater prevalence among them
• Relation to metaphor?
• Schizophrenics
LSD
• The threshold dosage level for an effect on humans is of the order of 20 to 30 µg (LSD is extremely potent)
• Doses can be as high as 1,200 µg but higher doses come with the increased risk of “bad trips”
• LSD affects a large number of the G protein coupled receptors, including all dopamine receptor subtypes, all adrenoreceptor subtypes and most serotonin receptor subtypes
• Initially used for psychotherapy
Sensory Effects of LSD
• Users experience Synesthesia
• “LSD does not produce hallucinations in the strict sense, but instead illusions and vivid daydream-like fantasies.”
• Visual Effects
• movement of static surfaces (walls breathing)
• geometric patterns and an intensification of colors and brightness
• Schizophrenics do not experience the effects of LSD
Alternate States and Additional Questions
• Could LSD be the gateway to the synesthesiac experience/consciousness?
• Are synesthetes experiencing the world at a level of consciousness different from the rest of us?
• Do we all have synesthesia at some level?
• Booba/Kiki
• Metaphor
• What about schizophrenics…
• they lack the ability to comprehend metaphor
• they do not experience the synesthesic effects of LSD
Sources• Ramachandran, V. S. & E. M. Hubbard (2001), "Synaesthesia: A window into
perception, thought and language", Journal of Consciousness Studies 8(12): 3-34
• Simner, J.; C. Mulvenna & N. Sagiv et al. (2006), "Synaesthesia: The prevalence of atypical cross-modal experiences", Perception 8(35): 1024-1033
• Wannerton, J. I., “The World of Synaesthesia”, http://www.wannerton.net/
• Synesthesia - Wikipedia, http://en.wikipedia.org/wiki/Synesthesia
• Ramachandran, V. S. and Hubbard, Ed (2003), Hearing Colors, Tasting Shapes, Scientific American, Vol 288 Issue 5 (May 2003), 42-49.
• Ramachandran, V. S. and Hubbard, E.M. (2001). Psychophysical investigations in to the neural basis of synaesthesia. Proceedings of the Royal Society, 268, 979-983.
• Ramachandran, V. S., Lecture, http://www.nyas.org/ebriefreps/ebrief/000500/presentations/ramachandran/player.html
• Duffy, P. L. (2001). Blue Cats and Chartreuse Kittens: How Synesthetes Color their Worlds. New York: Henry Holt & Company