The 11 types of synesthesia (and their characteristics)

Hear colors? Savor sounds? See the colored letters? Attribute personality to numbers?

As surprising as it may seem, there are not a few people who have the peculiarity of mixing sensations, a phenomenon known as synesthesia which can manifest itself in very different.

There are those who hear colors, others taste the letters or even see the touch... There are so many types of synesthesia that we could make an encyclopedia with them! Let's find out which ones are the main ones.

• Related article: "17 curiosities about human perception"

What is synesthesia?

Can you imagine a totally different way of perceiving reality? In school they taught us that there are 5 senses: hearing, taste, sight, touch and smell. These senses are each perceived by a different organ, in theory.

But, What would happen if when touching a surface with a certain texture we also heard a sound? What would the world look like if sounds were intermingled? Would it be chaos or an advantage? Read on to enter a totally different world.

All our lives we have heard that there are 5 senses (there really are more, but right now that debate does not concern us). Human beings have hearing, sight, taste, smell and touch and each of these senses is perceived with an organ different: we see with the eyes, we hear with the ears, we taste with the tongue, we smell with the nose and we touch with our skin. But what if when we touch something we hear a melody? What if hearing a song we saw a vivid multi-colored landscape? we call this synesthesia.

Synesthesia is a phenomenon by which sensory perception occurs simultaneously through two different senses, which are interconnected. For example, there are those who listen to music also see colors, while others associate letters, numbers or people's names with certain colors. Combinations of senses of all types can occur, which is why it is known that there are many different types of synesthesia, it is common for a person with synesthesia to also have a second or third modality of this peculiar phenomenon.

It seems that this phenomenon occurs more frequently in women, between 3 and 8 times more than men, and the reason for this is not known. You are also more likely to have synesthesia if you are left-handed. There is a hereditary component behind the appearance of the phenomenon, because in families that have a member who experiences synesthesia, there is a high probability that another member also presents this phenomenon, and it seems that it would be associated with X chromosome. It is also common in people with autism spectrum disorder.

Normally, synesthesia occurs with two of the five classical senses, although on quite rare occasions it may happen that three of them are involved. Regardless of how many senses are involved, this phenomenon seems to be very rare, with statistics suggesting that it would occur between 1 and 4% of the population, although there are studies that suggest that 15% of the general population would experience some type of synesthesia.

Despite how relatively common it could become, Many people don't even know they experience synesthesia! In fact, it is not surprising that synaesthetic people discover it by chance, discovering that smelling colors or seeing letters of different color is not normal.

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The main types of synesthesia

While all the senses can be combined in all possible ways, the most common perceptual interferences in the Synesthesia have to do with the senses of taste and hearing, being the color / tone correspondence one of the most frequent. Here are some examples of relatively common types of synesthesia.

1. Grapheme-color synesthesia

Grapheme-color synesthesia it is the most frequent type, estimating that it occurs in 49% of synesthetic people. It consists of seeing symbols of a certain color, such as letters and numbers or words as a whole.

The poem "Vowels" by the French poet Arthur Rimbaud is considered an example of this type of synesthesia in the art world.

A curiosity of this type of synesthesia is that there are some associations that are more common than others regardless of the person. For example, the association between the letter A and the color red is usually quite common in synesthetic people.

• Related article: "Psychology of color: meaning and curiosities of colors"

2. Chromesesthesia

Chromesthesia consists of sensory association between colors and sounds, including also the ability to perceive sounds or melodies by observing colors and the reverse process. Some studies indicate that 30% of synaesthetic people have chromesthesia.

Some well-known artists, such as the Russian painter Vasili Kandinsky and the poet Charles Baudelaire presented this type of synesthesia, and showed their particular sensory interferences in their artistic creation.

3. Lexical-gustatory synesthesia

People with lexical-gustatory synesthesia they perceive flavors when they hear a word, a type of sensory interference believed to affect less than 0.2% of the world's population.

A well-known example of this type of synesthesia is SOMEONE James Wannerton, a man who claims to savor a waffle every time he hears the word "basketball."

• You may be interested in: "Sense of taste: its components and how it works"

4. Synesthesia of personification

Personification-type synesthesia is truly curious and rare, consisting of perceive the "personality" of symbols such as letters or numbers. For example, it consists of seeing that W is a surly letter or that 7 is a stingy and malicious number.

5. Shaped numbers

Some synaesthetic people they see shapes when thinking in numbers, a type of synesthesia that was first described by the pioneer of statistics and psychometry Francis Galton in the late 19th century.

6. Space-time synesthesia

People with this type of synesthesia establish a very strong connection between the parameters of time and space, perceiving time as if it were a physical entity. They can organize time with shapes like squares, different sizes depending on how big or small the time period is, or even attribute colors to it.

7. Mirror-touch synesthesia

Mirror-touch synesthesia consists of the perception of tactile sensations when seeing that other people feel them, such as, for example, seeing someone touch a glass and feeling that it is their fingers that feel the cold and smooth touch of that surface.

It is inevitable to relate to mirror neurons of the brain, cells that are activated when we see someone do something and that is as if they represent in our mind the behavior we see in others.

Some have associated mirror-touch synesthesia with above-average levels of empathy.

8. Touch-emotion synesthesia

There are people that feel emotions when touching surfaces with certain textures, this type of synesthesia being extremely strange.

9. Auditory-tactile synesthesia

Auditory-tactile synesthesia implies that the person presenting it perceives physical sensations when hearing certain sounds. This type of synesthesia includes everything, ranging from relatively simple sensory interferences, such as hearing a screeching while touching a metal surface, to more complex situations such as hearing the word "Bolognese" when touching a stone.

• Related article: "The 5 auditory areas of the brain"

10. Spatial sequences

Spatial sequences are a type of synesthesia that consists of see numbers as points in space.

A common example of this phenomenon is seeing that the smallest numbers are close and the largest numbers are far away.

This type of synesthesia has been associated with having a better memory than the population average.

11. Linguistic ordinal personification

Linguistic ordinal personification is a peculiar phenomenon in which ordered sequences and personalities or genres are associated. An example would be to relate the number 5 with an obese person or enter the letter Y with an aerobics instructor.

How is synesthesia detected?

There are no single diagnostic criteria to detect synesthesia. Being an extremely rare neurological condition that can manifest itself in so many different ways, detecting it can be a real challenge. Fortunately, the American neurologist Richard Cytowic has proposed a series of criteria to facilitate the detection of cases of synesthesia.

First, synesthesia occurs involuntarily and is triggered by sensory input.

In addition, synaesthetic experiences are projected, that is, they are not seen with the “mental eye” (when we we imagine things), but they look as if it were really outside our body, as a stimulus real sensory.

It is a long-lasting and generic phenomenon, that is, the association between two or more senses and stimuli is maintained over time. For example, if a person sees the letter E as yellow, he will continue to see it as yellow in the long run, even though It should be said that there are cases of people who can change their way of perceiving certain sensations synesthetic. As for the generic, it refers to the fact that synaesthetic people tend to perceive sensations simple, for example, if they hear sounds they will rarely see a complex landscape, but rather shapes and colors simple.

Thanks to the fact that two or more senses are involved when perceiving the world, people with synesthesia often have a long memory. This is because they have more clues to remember what they have experienced. For example, if we are people who associate colors with words, maybe a term as long as "sternocleidomastoid" Let's see it in orange and associate it more easily with the anatomy lesson that we have had to memorize for the class of biology.