Synaesthesia
Life’s too confusing for this stuff…
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
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 – 1735- 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”
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
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Idea that it’s a mental illness is no longer valid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)
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)
References
• http://www.macalester.edu/~psych/whathap/
UBNRP/synesthesia/SYNBRA~1.HTM
– Great page, lots of information