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 (4 th 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What’s happening in the brain?• Idea that it’s a mental illness is no longer valid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