1. Life’s too confusing for this stuff…
Synaesthesia
Life’s too confusing for this stuff…

2. What is Synaesthesia?
Defined as “an involuntary physical experience of a cross-modal association”
Crossing of the senses
One stimulation of a sense causes the stimulation of another sense
Greek
Syn – together
Aisthesis – perception
Five main diagnostic features
Involuntary
Sensations projected onto environment (i.e. real)
Sensations remain the same with time and situation
Memorable (often most memorable)
Emotional – causes ecstasy

3. History of Synaesthesia
Possibly first identified/noted by Aristotle (4th century B.C.) or Pythagoras (6th century B.C.)
First reference believed to be in John Locke’s Essay Concerning Human Understanding
Speaks of a blind man interpreting scarlet as being like “the sound of a trumpet”.
Leibniz and Newton both mention in 1704
Leibniz – recounted again a case of a blind man interpreting scarlet as being like the sound of a trumpet
Newton – Attributed colors to notes of a musical scale
Castel – Noticed same parallel as Newton, and created first color organ
Galton – 1883 – noticed synaesthesia seemed to be frequent in children
Scriabin – 1911 – composed Prometheus
Incorporates music and light
1944 – attempt to teach “colored hearing”

4. Types of Synaesthesia  
Two or more senses crossed, usually unidirectional – 31 possible combinations
Two-Sensory:
Colored Hearing (Chromaesthesia)
Sound evokes perception of a color
Colored-Olfaction
Smell evokes color
Colored-Gustation
Taste evokes color
Tactile-Gustation
Taste experienced as shape
Multiple Sensory
Numbers, letters, words, dates, etc experienced as colors  

5. What’s happening in the brain?
Idea that it’s a mental illness is no longer valid
Positron Emission Tomography (PET) shows that different areas of the brain are active for a task for those with Synaesthesia than those without
Depends exclusively on the left brain
Associated with decreased blood supply to the neocortex, resulting in enhanced limbic expression
Leads to belief that synaesthesia is influenced more by limbic system than neocortex
Supported by the fact that there are emotions felt when a synaesthetic experience occurs
Idiopathic (natural/genetic)
Rebalancing of regional metabolism (similar to migraine)
Everyone perhaps Synaesthetic at birth, and some fail to have their senses modulated
Non-Idiopathic (developed)
Seizure (electrical discharge in brain) induced
Drug Induced
Neuron degeneration
Brain/Spinal damage
Concussion induced (noises/lights cause pain – temporary)

6. Living With Synaesthesia
Generalized Trends
Order, neatness, symmetry, balance
More prone to unusual experiences (déjà vu, etc.)
Right-left hand confusion
Math abilities and spatial navigation below average
Superior memories
Imagine:
Conversations being painful or pleasurable from flashes of color, and not being able to concentrate on what is being said
Voices blending together in a mix of colors
Fast speech bringing a confusing mix of pictures and/or colors
Remembering things, even in other languages, simply by association with another sense (pictures, for instance)

7. References
Great page, lots of information