Author: tgraven

Colours without vision

tgraven/ / Colour, Crossmodal correspondences, Posts, Vision

Colours are perceived solely through vision. Indeed, when S.B. gained sight after more than 50 years of blindness, he saw the world for the first time in colours. (See our blog for the scientific approach and Vision, haptic touch, and hearing.)

So, what is colour to people who are blind? This post presents some lived experiences.

The eye perceives colours when light reflects off an object. It detects their hue (e.g., red or orange), lightness or darkness (e.g., pink or red), and intensity (e.g., bright or dull yellow). Various devices, smartphone apps, and a braille-like alphabet have been developed to convey this information to people who are blind. While sighted adults and children rather describe:

– the colours through their other senses. For example, that “pink is fangirls screaming”

– what colours do. For example, that red attracts their attention

– how colours make them feel. For example, that blue relaxes them

 

“So, being blind since birth, I’ve never seen color. I don’t have any concept of what it is (…) there’s this whole part of vocabulary of language that doesn’t mean anything to me. Over the years people have tried and tried to explain color to me, and I just don’t understand it.”

“Because I have never seen colors, I don’t think I really understand what they are. However, I do know the color of many things: crows are black, leaves are green, and hair may be blonde, brown, red, black, gray, white — or dyed any color a person desires. I also know colors are highly symbolic in our culture: “I was so angry, I saw red.” Or, ‘I was tickled pink.’”

In fact, the concept of colour is just as abstract for people who are born blind as the concept of justice. Both are learnt through language, by reading and hearing about them.

 

“Ocean green smells so nice, it’s my favourite colour.” (M.O.)

“(…) right now my favorite color is purple, and that is because of my musical hero Prince. Everything he had and did, purple was his thing so I just figured why not. I like Prince, therefore I like purple. I’m not quite sure what I understand about the color purple. I mean it’s not as popular as red, green, orange, or blue or any of those, right? I hear about those things all the time, but I don’t hear about purple that much. As far as purple stuff? I’m not quite sure. Grapes are purple. I know that. I’m not quite sure what else in nature is purple, though? I don’t know. It feels like it’s sort of a strange color. It’s not in the rainbow. What else is purple?”

For sighted people, the concept of colour has sensory qualities and is, therefore, represented in a different part of the brain than the concept of justice.

But what if vision is lost later in life?

 

“So, to me, blue is swimming in a pool, or running my hands under water. Yellow is the heat from the sun (…). When I think of purple, I think of feeling peaceful and calm, or the texture of velvet. When I think of black, I think of a fluffy cat. When I think of white I think of cotton balls, overly soft blankets. And green is the smell of fresh cut grass or walking barefoot in the summer.”

“I group colours into large temperature groups, and narrow it down from there using my other senses. Is it warm like pink, red, orange or yellow? (…) Is it a combination colour like peach which I conceptualize as pink/orange? (…) I keep the relationships memorized. If it’s two-colour combination of warm, a cool or a neutral, I’m usually OK. Then I group colours into three main shade categories. (…) Light/pastel, medium, and dark. I also love when colours are compared to my other senses that don’t involve vision. Like saying something is green like lush summer grass or saying something is brown like a piece of rich dark chocolate.”

B.T., who lost his vision more than 20 years ago, explained that his memory of colours is decaying. Although he remembers them, their hue, their lightness or darkness, and their intensity are no longer as clear as they once were. But not in his dreams. When B.T. is fast asleep and dreaming, the colours are still both nuanced and vivid. (See our blog for the Decay and maintenance of sensory memories and the Visual memories and sensory experiences.)

When vision is absent from birth, colour is just a sum of learnt information. Even black – people who are blind do also not see the colour black. To them, colour is an abstract concept. And, for those who lose vision later in life, there are no crossmodal correspondences that transfers information from the sense of hearing, smell, taste, or touch to vision: colour is solely visual. (See our blog for the crossmodal correspondences between the senses.) It seems they have to actively create and learn associations between their memory of each colour and their other senses, as well as systems for memorising them. Or else their memories will decay.

See our blog for Activities; especially 52-54.

Visual memories and sensory experiences

tgraven/ / Crossmodal brain plasticity, Crossmodal correspondences, Haptic touch, Hearing, Multisensory, Posts, Smell, Taste, Vision

It seems people who lose vision use information that transfers between the senses to retrieve visual memories. And that their visual memories decay when they have reached a certain level of experience in the other senses. (See our blog for the scientific approach, the crossmodal correspondences between the senses, and Decay and maintenance of sensory memories). But what happens when people who are born blind gain vision and then lose it again?

I have invited P.B. to share his experiences of visual memories and sensory information when going from blind to partially sighted and back to being blind again. P.B. was born blind with some light perception in one eye. After surgery and other medical treatments, he had gained about 7% vision in the other eye at three and a half years old. P.B. does not remember this shift from being blind to being partially sighted. Then, in his early twenties, P.B. had an accident that rendered him totally blind in both eyes. P.B. thinks of himself as a sighted person who happens not to see. He visualises when making plans. And his dreams are always visual. P.B. approved this text before we posted it on our blog.

P.B. has several visual memories from when he was little. From the house he grew up in, for example, he remembers the light from a chandelier hanging over the coffee table in the living room, the patterned wallpaper in his room, and the countries on the world map hanging on the wall. And he remembers the colours on the outside walls, the doors, and the window frames.

Today, when he has no new visual input, P.B. creates visual images based on his memories and knowledge. For example, that of a White Swiss Shepherd Dog working as a guide dog from his memories of both the white colour and the German Shepherd Dog. As well as his knowledge of guide dogs.

His visual memories are typically triggered by somebody describing how something looks, like a bright red sunset – not by information from the other senses.

P.B.’s visual memories “flash up almost like the flavour when eating or drinking”.

He has to decide not to focus on visual memories and images when talking to people: the memories are now 20 years old and people have changed. And his created visual images of what new people look like may be very wrong.

P.B. has to actively suppress his urge to retrieve visual memories or create visual images of people based on their voices.

He describes not having visual memories and images of spatial relations and distances. P.B. rather remembers them through his body. He walks around in the city centre with no vision, a podcast or some music in his ears, and shoes with a thick curved sole (which makes it difficult to feel the surfaces on pavements, streets, steps, floors, etc.). He does not count steps or any of that and pauses the podcast or music in his ears only when he feels he might get lost.

For P.B., sensory experiences include a variety of simultaneous sensations as well as visual memories and created images – they are multisensory. The forest, for example, is the sound of wind and trees, the texture of surfaces under his feet, scents, and the memories of colours. He zooms in on whatever attracts his attention: indeed, not on one piece of sensory information after the other in a certain order. For example, zooming in on a sudden shift from soft to hard texture under his feet.

An interesting sensory experience, according to P.B., is that of new flavours, the texture of the food, and the sound of crunch when chewing, He describes a cloudberry cream dessert as “not very sweet, but also not sour, light orange colour, and creamy texture”. But a redcurrant jelly only as “something wobbling on the plate”. He does not describe the flavour, scent, and/or feel in his mouth – merely how the jelly looks on the plate.

Was he not able to suppress his visual memories of jelly – did they take over?

When P.B. is sensory tired, he relaxes his senses by listening to “concentration music, like opera or prog rock where I can immerse myself and get absorbed by a different universe”.

It seems P.B. can maintain his visual memories and ability to create visual images through people’s descriptions of what something looks like. But, at the same time, these memories and images are distracting him from focusing on sensory information that is more relevant to him today with no vision, for example, people’s voices and the feel of wobbling jelly in his mouth, So is this, in fact, a negative spiral – that maintaining visual memories prevents experiences in the other senses, which in turn helps nurture the visual memories?

See our blog for Activities; especially 49-51.