Lecture Notes: Synesthesia

Introduction to Synesthesia

• Definition: A neurological phenomenon where two or more senses are coupled.
  • Example: Seeing numbers and letters as colored despite being printed in black.
  • Synesthesia affects 4% of the population.
• Types of Sensory Couplings:
  • Hearing a voice and seeing it, tasting it, or feeling it as a touch.
  • Words and names can evoke unusual flavors (e.g., 'jail' tastes like bacon).

Characteristics of Synesthesia

• Terminology:
  • "Synesthesia" means joint sensation.
  • Opposite of "anesthesia", which means no sensation.
• Prevalence:
  • Having one type gives a 50% chance of having additional types.
  • 1 in 90 people experiences graphemes as colored.
• Personification:
  • Numbers or letters can have genders or personalities.
  • Example: '3' is sporty, '9' is elitist.

Synesthetic Experiences

• Phonemes and Tastes:
  • Certain sound units trigger synesthetic tastes (e.g., 'college' tastes like sausage).
• Memory Benefits:
  • Synesthetes have superior memories due to sensory "hooks".
• Lifetime Pairings:
  • Pairings established in childhood are fixed for life.

Biological Basis of Synesthesia

• Genetic Inheritance:
  • Propensity for hyper-connecting neurons is inherited.
  • Requires exposure to cultural artifacts (e.g., alphabets, food names).
• DNA Mutation:
  • A single nucleotide change in DNA can alter perception.

Broader Implications and Metaphorical Thinking

• Understanding Subjective Differences:
  • Synesthesia helps understand why people perceive things differently.
• Creativity and Metaphor:
  • Synesthesia is common in artists and enhances metaphorical thinking.
  • Examples: Vladimir Nabokov, David Hockney, Billy Joel, Lady Gaga.

Synesthesia and General Perception

• Metaphor Comprehension:
  • Non-synesthetes can understand metaphors due to inherent sensory mapping.
• Cross-talk in the Brain:
  • Perceptual couplings occur naturally for everyone, even if unconsciously.

Conclusion

• Reflection:
  • Synesthesia exemplifies the natural cross-talk in our brains and enhances our understanding of metaphors and perception.
• Key Insight:
  • The phenomenon highlights how deeply interconnected our sensory experiences are.