David Brang Anna KrasnoLee Edwards Amanda Gorlick
Cogs 1756/2/06
Outline
• 1. Lee - Synesthesia Primer– What it is, relation to consciousness
• 2. David– Video, demographics, evidence, theories
• 3. Anna– Acquired synesthesia, developmental vs. acquired
• 4. Amanda– Conscious understanding - closing remarks
What is Synesthesia?
• Perceptual phenomenon• Grapheme Color• Inducer and concurrent• Developmental synesthetes• No Comorbidity with mental
illness
Correlates to Consciousness
• Can be thought of as an altered state• The world is perceived differently,
relative to non-synesthetes• Cross modal integration• Relevance
Demographics• The majority of synesthetes
report the experience since childhood
• Occurs in at least 1/2000 individuals
• More common in children than adults
• More common in women• Has a genetic basis to it• Theorized 50 separate forms of
synesthesia
Evidence as a Phenomenon
• Test/retest reliability• Similar reports across
cultures and time• PET studies• fMRI studies• Synesthetic Stroop Test
Theories
• Learned association• Awareness• Neural Connectivity
– Neonatal– Cross-wiring
• Disinhibited feedback• Gamma-Binding
Acquired
• Brain damage• Retinitis pigmentosa• Sensory deafferentation• Drugs• Meditation
Developmental vs. AcquiredDevlopmental Acquired
Involuntary Transient experience
Synthetic Perception and Conception
Perception only
Consistent across lifetime
Not verifiable over time
Part of normal consciousness
Not brought into self-awareness
Often unreported Novelty of event communicated
Pop-out Effects
Towards a Conscious Understanding
• Booba and kiki– “Conceptual rightness”
• Synesthesia is present and suppressed in normal individuals, but has the potential to rise to consciousness
• Only consistently part of consciousness in developmental synesthetes
Conclusion
• Altered state is unique to the baseline state of each individual
• Umbrella including autism and other developmental disorders
• Personal reality
References• Baron-Cohen, Simon. (1996) “Is there a normal phase of synesthesia in
development? Psyche, 2(27)• Calkins, M.W. (1893). “A statistical study of pseudo-chromesthesia and of
mental-forms.” American Journal of Psychology, 5, 439-66.• Cytowic, R.E. (1989). “Synesthesia: A Union of the Senses.” Springer Verlag.• Galton, F. (1880). “Visualized numerals.” Nature, 21: 252-256. • Grossenbacher, P.G. & Lovelace, C.T. (2001). “Mechanisms of synesthesia:
cognitive and physiological constraints.” TRENDS in Cognitive Sciences, 5: 36-41.
• Hubbard, Edward M. and V.S. Ramachandran. (2005) “Neurocognitive Mechanisms of
• Synesthesia.” Neuron, 48:509-520.• Lynn C. Robertson & Noam Sagiv (Eds). Synesthesia: Perspectives from
Cognitive Neuroscience. New York: Oxford University Press, 2005. • Maurer, D. et al., (1999). “Cross-modal transfer of shape is difficult to
demonstrate in one-month-olds.” Child Development, 70 (5), 1047-57.
References• Nunn, J.A. et al., (2002). “Functional magnetic resonance imaging of
synesthesia: activation of V4/V8 by spoken words.” Nature Neuroscience, 5: 371-375.
• Paulesu, E. et al. (1995). “The Physiology of Coloured Hearing: A PET activation study of colour-word synaesthesia.” Brain, 118, 661-676.
• Ramachandran, V.S. and Hubbard, E.M. (2003). “Hearing colors, tasting shapes.” Scientific American. May 2003, 53-59.
• Ramachandran, V.S. & Hubbard, E.M. (2000). “Psychophysical investigations into the neural basis of synaesthesis.” The Royal Society, 268: 979-983.
• Rich, A.N, Bradshaw, J.L., J.B. Mattingley. (2004). “A Systematic, largescale study of synesthesia: Implications for the role of early experience in lexical-colour associations.” Cognition. 20(11): 1-32.
• Snyder, S.H. (1986). Drugs and the Brain. New York: Scientific American Library.
• Van Leeuwen, T. (2004) “The neural basis of synesthesia.” <http://bar.psych.ubc.ca/PDF/VanLeeuwen04_synpaper.pdf> May 28, 2006.
• Walsh, R. (2005). “Can synesthesia be cultivated?: Indications from surveys of meditators.” Journal of Consciousness Studies, 12, 5-17.