What is synesthesia?

Synesthesia is a rare condition that connects one sensory stimulus to another sensory stimulus or more than one sensory stimulus. People with this condition can see what they hear or might even be able to taste it. 

The condition is known to overlap or combine our senses so that we feel various combinations of senses with the stimulation of even a single sensory organ.

It is defined as a neurological occurrence in which the voluntary or involuntary stimulation of a single sense gives rise to the involuntary stimulation of another sense or a few other senses. 

There can be several types of synesthesia since various sequences of overlapping senses might occur to various individuals. It is said that this condition is found in not more than 4% of the population of the world. 

‘The Sound Machine’ by Roald Dahl can be referenced to understand synesthesia better. The protagonist of the short story might have designed a machine to hear the sounds that the human ear cannot perceive but the outcome of using the sound machine and being able to visualize a sound while looking at something can rightly explain synesthesia. 

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What are the different types of synesthesia and how does it occur? 

Synesthesia is said to occur when the different parts of our brain that deal with a sensory stimulus are located close to one another. In such cases, if one part of the brain is stimulated, it automatically stimulates the other overlapping part, thereby causing synesthesia. It is an inherent condition and is mostly found since a very early stage in life or from birth. 

Temporary synesthesia is way more common than the inherent condition. Temporary synesthesia can occur due to the consumption of alcohol, drugs, caffeine, etc.

Synesthetes might perceive certain stimulations together but in certain cases, it’s so inherent that they do not even realize that they have synesthesia unless someone in their close surroundings notices it and makes them aware of the same. 

Types of synesthesia

1. Grapheme Color Synesthesia


This is the most common type of synesthesia and in such a condition, synesthetes are seen to connect numbers as well as alphabets with certain colors. People with this condition might as well connect a particular number or an alphabet to a particular color, which the others would not relate to. 

Example – Red color is connected to the letter ‘A’.

2. Personification

As the name suggests, this particular synesthesia type is a condition where the synesthetes might be able to associate character types or personality traits with the letters or the numbers that they see or are familiar with, much like the conventional assigning of character types to individuals. 

Example – The letter F might have a bubbly personality and the month of April might be a cheerful month. 

3. Mirror-touch synesthesia


In such a condition, the synesthete is found to feel certain physical sensations or sensations on the skin or body by viewing the same happening to someone else.

The absurdity of this condition lies in the fact that the synesthete is not even in direct or indirect contact with the source that causes a physical sensation in somebody else. 

Example – A synesthete might feel pain if they see somebody getting hit. 

4. Chromesthesia

Types of synesthesia include this common phenomenon that enables synesthetes to interlink the perceptions of sound and color. It refers to sound to color or color to sound synesthesia.

Specific colors are associated with certain sounds. Such synesthetes involuntarily feel the sensation of color when they hear something or vice versa. 

Example – darker and warmer colors might be associated with lower, less shrill sounds. 

5. Auditory-Tactile Synesthesia


As mentioned before, synesthesia types might involve diverse combinations of senses. Auditory-Tactile or ear to skin refers to the feeling of physical sensations due to the perception of specific sounds.

Some sounds might have a positive impact on the skin of synesthetes and make them feel relaxed whereas some have been found to cause immense physical pain. 

Example – Somebody’s voice can result in the feeling of burning on the skin. 

6. Spatial Sequence Synesthesia

Synesthetes can link certain numbers, alphabets, days, etc with definite spatial positions or sequences. These sequences or patterns might vary or have numerous forms.

Associating data with sequences or patterns helps to remember things better and such synesthetes are seen to have a better memory than an average individual. 

Example – While perceiving numbers, a synesthete may be able to view the number ‘5’ nearer or bigger than the number ‘7’, which appears farther and smaller. 

7. Misophonia


This is one of the most uncomfortable synesthesia types and refers to the feeling of discomfort or irritation due to the perception of some sounds that are otherwise quite common.

Such synesthetes are usually kept isolated because of their sudden and violent outbursts after hearing a certain sound. There should be constant professional guidance while dealing with synesthetes of this sort. 

For example – the sound of footsteps might trigger the synesthete and they may become immensely violent. 

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8. Lexical-Gustatory Synesthesia

Synesthetes associate tastes and colors with particular words. It has been noticed that certain words have a greater intensity of taste or smell perceptions than other words whereas, viewing or hearing certain words might lead to no perception at all. 

Example – The word ‘bowl’ cant lead to the perception of a definite smell or taste. 

The numerous types of synesthesia that are cited above don’t have any scientific cure or way of treatment since these conditions are innate.

However, the cases that lead to violent outbursts or reactions should be reported to doctors and health experts and the synesthetes should be made to attend regular therapy sessions to calm down their nerves and curtail their discomfort. 

Synesthetes who’re under regular medication do not consume medicines that are meant to cure synesthesia but instead, consume nerve relaxant medicines and sedatives. On the other hand, some synesthetes consider themselves unique, owing to their special abilities. 

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