Who doesn't like songs with a lot of red?

Updated: Jun 2

Once at sundown when my roommate (X) and I were on the patio listening to Gregory Alan Isakov, out of the most peaceful quiet he said I see a beach and people around a campfire. This happens every time I listen to that part of the song”.

The excitement in his voice suggested that he wasn't talking about an old memory.

The beach, the blonde woman and the goldfish were all things he saw vividly when he listened to sequences of musical notes. Not whole songs or even his favourite parts. "Insignificant snippets!". The things he saw were "less real than the rest of the world" but certainly "more real than the stuff of imagination". When I narrated the incident to a neuroscientist friend (Y) of mine (who I expected to assure me that my roommate was full of shit) she said she had a similar quirk! Every time she did calculations in her mind, she saw a spatial representation of the arithmetic operation. If she added an eight to a ninety two, she could see a smaller eight block bang into a bigger ninety two block creating a perfect hundred.

In the 1980s, the American Neurologist Richard Cytowic encountered similar accounts and rediscovered the psychological phenomenon known as synesthesia. Synesthesia (now an active field of scientific inquiry) is a condition in which perception through one mode of the human senses (Visual, Auditory, Olfactory, Tactile or Gustatory) produces a conjoined perception in another.

It has changed our understanding of the inner worlds that humans inhabit and its endless varieties. About four percent of the world's population is believed to have some sort of synesthesia. The most common combination in synesthesia appears to be sound with sight, called Chromesthesia.

Annie Elise, a musician has two-way Chromesthesia – sounds make her see colours and colours make her hear sounds. The following video made by Annie can help you get an idea of what she experiences.

Ideasthesia is a subset of synesthesia where (like for Y) the synesthetic percepts are caused by concepts like numbers. There are numerous types of synesthesia including ones where times of the day have tastes and orgasms have colour.


Tests of synesthesia involve recording the correlation between inducers and concurrents over time to look for consistency. For someone with coloured hearing like Annie Elise, the inducer is sound (sensory modality that induces sensation) and concurrent (sensory modality in which sensation is induced) is colour. We ask subjects to indicate the colour corresponding to distinct sounds and record their responses. The process is repeated multiple times over months or years with the same sound clips. If the reported correlation does not change over time, it means that the condition is real.

Imaging techniques like FMRI can also help verify claims of having synesthesia. For example, scientists have reported activation of areas of the left cerebral hemisphere called V4 and V8 (related with colour sensing in humans) in response to sounds in people with chromesthesia. This does not happen in non-synesthetes [2].


Solomon Shereshevsky

Solomon Shereshevsky, renowned in the field of psychology as famous psychologist Alexander Luria’s patient ‘S’ was a Russian mnemonist (a ‘mnemonist’ is a person with an astonishingly powerful ability for recollection, innate or attained through training). He initially worked as a journalist and his ability to reproduce speeches he had heard verbatim, without taking any notes brought him to the attention of Luria.

He became the subject of Luria’s book “The mind of a Mnemonist”. Luria discovered that ‘S’ had an extreme case of synaesthesia - every word summoned for him a distinct shape, colour and taste. This gave ‘S’ a vivid impression of every word he heard or read, having connected them with an everlasting eidetic image. The condition enhanced his ability for recollection, which he used during his time as a performing mnemonist.

‘S’ was among the rare few for whom synesthesia was debilitating. He was often so lost in his subjective reality - a storm of eidetic imagery and tastes evoked by words that he was unable to follow the intended messages in conversations.

Reality was a fluid entity: the taste of restaurant food changed with the music being played, or he could not eat and read at the same time because the food’s flavor intruded into his perception of the written words.
– Richard E. Cytowic on 'S', A union of the senses

Vladimir Nobokov

Vladimir Nobokov was a Russian novelist, poet and entomomlogist. Nobokov’s magnum opus, ‘Lolita’ was adjudged the fourth best novel of the 20th century by Modern Library.

"I think I was born a painter-- really!-- and up to my fourteenth year, perhaps, I used to spend most of the day drawing and painting and I was supposed to become a painter in due time. But I don't think I had any real talent there. However, the sense of color, the love of color, I've had all my life: and also I have this rather freakish gift of seeing letters in color. It's called color hearing. Perhaps one in a thousand has that."
- Nobokov during his 1962 interview with BBC

Nobokov had Grapheme-colour synesthesia, one of the most common and well-studied types of synesthesia. For people with this type of synesthesia, letters and numbers have the inherent property of colour. They however also see the letters and numbers (collectively called graphemes) like non-synesthetes. For instance, they may see words in a newspaper in black type with an additional experience of colour.

There is a disagreement among synesthetes as to where the colour exists. For some, the graphemes cause photisms (speckles of colour in the visual field). For some, the graphemes are overlayed by a veneer of colour or they “know” that a grapheme is a certain colour. For yet some others, the colour is in their mind’s eye.

Richard Feynman

Richard Feynman was one of the most influential physicists of the 20th century. Every student of physics has probably read The Feynman Lectures on Physics, a compilation of his famed lectures given at CALTECH.

Apart from being a Nobel-prize winning theoretical physicist and lecturer par excellence, he was also an avid Bongos player. Grapheme-colour synesthesia was one of his many quirks.

“When I see equations, I see the letters in colors – I don't know why. As I'm talking, I see vague pictures of Bessel functions from Jahnke and Emde's book, with light-tan j's, slightly violet-bluish n's, and dark brown x's flying around. And I wonder what the hell it must look like to the students”
- Richard Feynman, What do you care what other people think?

Perception of colour in grapheme-colour synesthesia has been shown to occur at early stages of visual perception in some synesthetes. This means that synesthetes perceive colour before conceptual processing of graphemes, probably along with processing of form information. Synesthetes can pick out numbers or alphabets from a group of similar forms faster than non-synesthetes thanks to their distinct colour (such as a 2 from a distractor group of 5s). Maybe this gave Mr. Feynman some advantage when sorting symbols and doing math.

How a non-synesthete sees versus how a synesthete sees alphabets (Palmeri et al., 2002)

Michael Watson

Michael is the title character in Richard Cytowic's book "The man who tasted shapes".

Michael's synesthesia bound together his sense of taste with his perception of touch. For michael, tasting mint felt like running his hands around cold ice columns. The correlation between tastes and corresponding shapes were so consistent that he used the changing shapes to guide his cooking.

"When I taste something with an intense flavor the feeling sweeps down my arm into my fingertips. I feel it. Like I'm actually grasping something."
- Cytowic quoting Michael, The man who tasted shapes

Madame L

One can often come to like names of people they like and hate names of people they don't like. Names pick up the flavors of people who have them although the constituent alphabets usually have no emotional valency.

Ordinal Linguistic Personification is a kind of synaesthesia that endows numbers, alphabets, days of the week and months in a year with personalities. For Madame L., not only do numbers and alphabets have personalities, they have complex relationships between them.

"1, 2, 3 are children [who] play together. 4 is a good peaceful woman, absorbed by down-to-earth occupations ... 5 is a young man, ordinary and common in his tastes and appearance, but extravagant and self-centered. 6 is a young man ... polite, gentle, ... average intelligence; orphan. 7 is a bad sort, although brought up well; spiritual, extravagant, gay, likeable; capable of very good actions on occasion ... 8 is a very dignified lady, who acts appropriately.... She is the wife of 9 [who is] self-centered, maniacal, grumpy, endlessly reproaching his wife for one thing or another."
- Simner and Holenstein, 2007

Synesthesia where people (like Y) have spatial representation of numbers (number forms) have been reported starting in 1880 by Francis Dalton. However a composite collection of musical notes eliciting a composite fully formed picture is unheard of. Why X sees images while listening to a set of musical notes remains a mystery.

Humans use one's own subjective experiences as reference to understand the experiences of others. Synesthesia represents one situation where this way of referencing fails to produce coherent models. It seems possible that we all inhabit at least slightly different inner worlds. We may never be able to make sense of some experiences of other people or animals due to differences in how brains are wired.



  1. Cytowic, R. E. (1989). Synaesthesia: a union of the senses. New York: Springer-Verlag.

  2. Gray, J.A. & S, Chopping & J, Nunn & D, Parslow & Gregory, Lloyd & Williams, Steven & M.J, Brammer & Baron-Cohen, Simon. (2002). Implications of Synaesthesia for Functionalism: Theory and Experiments. Journal of Consciousness Studies. 9. 5-31.

  3. Hubbard, Edward & Ramachandran, Vilayanur. (2005). Neurocognitive Mechanisms of Synesthesia. Neuron. 48. 509-20.

  4. Dixon, Mike & Smilek, Daniel. (2005). The Importance of Individual Differences in Grapheme-Color Synesthesia. Neuron. 45. 821-3.

  5. Palmeri, Thomas & Blake, Randolph & Marois, Rene & Flanery, Marci & Whetsell, William. (2002). The perceptual reality of synesthetic color. Proceedings of the National Academy of Sciences of the United States of America. 99. 4127-31.

  6. Simner, Julia & Holenstein, Emma. (2007). Ordinal Linguistic Personification as a Variant of Synesthesia. Journal of cognitive neuroscience. 19. 694-703.

  7. Feynman, R. (1988). What do you care what other people think? New York: W.W. Norton.

  8. Galton, F. (1880) Visualised Numerals . Nature21, 252–256 .