The 11 types of synaesthesia (and their characteristics)

These are the main types of synesthesia, variants of a curious phenomenon of perception.

Hearing colors, tasting sounds, seeing colored letters, attributing personality to numbers?

Surprising as it may seem, there are many people who have the peculiarity of mixing sensations, a phenomenon known as synaesthesia, which can manifest itself in very different ways.

Some people hear colors, others taste letters or even see touch? There are so many types of synesthesia we could make an encyclopedia of them! Let's discover which are the main ones.

What is synesthesia?

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

But, But what would happen if touching a surface with a certain texture also made us hear a sound? What would the world look like if the 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 (actually there are more, but we are not concerned with that debate right now). Humans have hearing, sight, taste, smell and touch and each of these senses is perceived with a different organ: we see with our eyes, hear with our ears, taste with our tongue, smell with our nose and touch with our skin. But what would happen if we heard a melody when we touched something, and if we saw a vivid multicolored landscape when we heard a song? We call this synesthesia.

Synaesthesia is a phenomenon whereby sensory perception occurs simultaneously through two different senses, which are interconnected.. For example, some people also see colors when listening to music, while others associate letters, numbers or people's names to certain colors. There can be combinations of senses of all types, which is why it is known that there are many different types of synesthesia, being common for a person with synesthesia to also have a second or third mode 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. It is also more likely to have synesthesia if you are a left-handed person. There is a hereditary component behind the appearance of the phenomenon, since in families with 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 to the X chromosome. It is also frequent in people with autism spectrum disorder.

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

Despite how relatively common it may be, many people don't even know it's there, many people don't even know they experience synaesthesia! In fact, it is not unusual for synaesthetic people to discover it by pure chance, discovering that smelling colors or seeing letters in different colors is not normal.

The main types of synesthesia

Although all senses can be combined in all possible ways, the most common perceptual interferences of 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 synaesthesia.

1. Grapheme-color synaesthesia

Grapheme-color synaesthesia is the most frequent type, occurring in an estimated 49% of synaesthetic persons.. It consists of seeing symbols, such as letters and numbers or words as a whole, in a certain color.

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 synaesthetic people.

2. Chromesthesia

Chromesthesia consists of the sensory association between colors and sounds, including also the capacity to perceive sounds or melodies when observing colors and the inverse process.. Some studies point out that 30% of synaesthetic persons present 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 synaesthesia

People with lexical-gustatory synaesthesia perceive flavors when hearing a wordThis type of sensory interference is believed to affect less than 0.2% of the world's population.

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

4. Personification synesthesia

Personification-type synesthesia is truly curious and rare, consisting of perceiving 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 people without aesthetics see shapes when thinking about numbersA type of synesthesia that was first described by statistical and psychometric pioneer Francis Galton in the late 19th century.

6. Space-time synesthesia

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

7. Touch-mirror synesthesia

Touch-mirror synaesthesia consists of the perception of tactile sensations by seeing other people feel them.For example, seeing someone touching a glass and feeling that it is your fingers that feel the cold, smooth touch of that surface.

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

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

8. Touch-emotion synesthesia

There are people who feel emotions when touching surfaces with certain textures, being this type of synesthesiaThis type of synesthesia is extremely rare.

9. Auditory-tactile synesthesia

The auditory-tactile synesthesia implies that the person who presents it perceives physical sensations when hearing certain sounds. This type of synesthesia includes everything from relatively simple sensory interferences, such as hearing a squeak while touching a metal surface, to more complex situations such as hearing the word "bolognese" when touching a stone.

10. Spatial sequences

Spatial sequences are a type of synaesthesia that consists in seeing numbers as if they were points in space..

A common example of this phenomenon is seeing smaller numbers close together and larger numbers far apart.

This type of synesthesia has been related to having a better memory than the average population.

11. Linguistic ordinal personification

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

How is synesthesia detected?

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

First, synesthesia occurs involuntarily and is triggered by a sensory stimulus.

In addition, synaesthetic experiences are projected, i.e., they are not seen with the "mental eye" (when we imagine things), but are seen as if they were really outside our body, as a real sensory stimulus.

It is a lasting and generic phenomenon, i.e., 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 term, although it must be said that there are cases of people who may change their way of perceiving certain synaesthetic sensations. In terms of the generic, synaesthetic people tend to perceive simple sensations, for example, if they hear sounds they will rarely see a complex landscape, but rather simple shapes and colors.

Because two or more senses are involved in perceiving the world, people with synaesthesia 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, we may see a term as long as "sternocleidomastoid" in orange and associate it more easily with the anatomy lesson we have to memorize for biology class.