Here’s the short soundbite-explanation of synesthesia:
Synesthesia is a neurological condition in which one sensory input to the brain triggers something additional, usually another sense.
Here’s a definition from wikipedia:
Synesthesia (also spelled synæsthesia or synaesthesia; from the Ancient Greek σύν syn, “together”, and αἴσθησις aisthēsis, “sensation”) is a perceptual phenomenon in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway. People who report a lifelong history of such experiences are known as synesthetes.
Here’s one from Psychology Today:
Synesthesia is a neurological condition in which a person experiences “crossed” responses to stimuli. It occurs when stimulation of one sensory or cognitive pathway (e.g., hearing) leads to automatic, involuntary experiences in a second sensory or cognitive pathway (e.g., vision).
There is a huge variety in the expression of synesthesia! Synesthesia primarily deals with sensory input to the brain, meaning conceivably you could (and do) find every combination of senses, such as
- hearing to color (chromesthesia)
- sound to touch (auditory-tactile synesthesia)
- graphemes/language to taste (lexical-gustatory synesthesia)
Ah, that sounds like some creative people getting carried away being too creative. That sounds way too strange to be real.
Synesthesia is a real phenomenon, and there is science to prove it. In his book “Synesthesia: A Union of the Senses”, neuroscientist Dr. Richard Cytowic “lays out the phenomenology of synesthesia in detail and gives criteria for clinical diagnosis and an objective “test of genuineness.”
A simple way to demonstrate the validity of synesthesia is to have a synesthete describe aspects of their experience, then have them do it again at a (possibly much) later date.
One of the primary indicators of synesthesia is that the associations, such as certain colors to certain graphemes or sounds, are extremely specific (a very particular shade of a color) and non-changing (the letter “L” was the same color 10 years ago).
My Chromesthesia (sound to color synesthesia)
Probably the most relevent and easy to understand manifestation of my own synesthesia is that I see sound. Not figuratively or metaphorically; I literally see it.
When I hear a sound, any sound, I also see it; for me there is no difference between hearing a sound and seeing a sound. When the microwave beeps I see a little red dot. I can’t separate the sound of the microwave from the appearance of the sound – they are the same thing!
This applies to any and every sound. Dogs barking, the wind, cars, talking, singing, musical instruments, static, motors, leaves, footsteps, water, bird calls, squirrels eating walnuts; these all have their own colors, shapes, and textures that I experience automatically and, importantly, completely involuntarily. In other words, I have no control over my experience of these mixed senses aside from literally covering my ears. If the microwave is repeatedly beeping, I will see little red dots until it stops.