Synesthesia

What is Synesthesia?

Synesthesia is a neurological condition that creates mixed sensations. It occurs when stimuli in one sensory modality (hearing, sight, taste, pressure, smell, touch, temperature…) are involuntarily perceived using another sense.

For example, a person affected by synesthesia can visualize colors when hearing a sound or perceive a face or a shape as a flavor or smell…

The term ‘synesthesia’ is a combination of the two Greek words ‘syn’ (which means ‘together’) and ‘aisthetis‘ (‘perception’) and the name literally translates into “union of the senses.”

To some extent, many people experience this kind of phenomenon in a mild form called grapheme-color synesthesia  when they permanently connect a certain color to a letter or a specific digit.

It is hard to estimate how many people are affected by synesthesia due to the lack of standardized diagnostic tests and to the fact that many individuals might not even be aware of their condition because for them the pairing is what they have always experienced.

Estimates, therefore, vary greatly and range from 1 in 20 people to 1 in 100,000.

Women seem to be more likely to have synesthesia together with left-handed people and the condition seem to be inheritable.

Causes that can trigger synesthesia are not clearly defined. Since common forms of synethesia affect letters, shapes and numbers it might seem logical to conclude that the condition occurs quite early in the first years of development, when a child is first exposed to abstract concepts.

Some researchers attribute this phenomenon to a biological cross-wiring between different areas of the brain and they believe that these connections between remote areas of the brain is present since birth.

Others seems to point at other causes, such as a disinhibited feedback processes that can also be experienced by people who don’t have synethesia in acquired forms for example as a consequence of brain injury, epilepsy, stroke, brain tumors or under the influence of certain drugs.

What are the Symptoms of Synesthesia?

Synesthetes (people who experience synethesia)  perceive stimuli with a different sense than the majority of individuals. This disorder can involve any of the senses. Therefore, synesthetes can hear sounds in response to smell, see colors instead of sounds, taste a specific flavor when looking at objects or people, smell in response to touch.

These people might even experience feelings in response to visual stimuli. The condition can basically involve one or more of the senses and any combination is basically possible even though only in very rare cases the disorder affects three or more senses simultaneously.

Since a synethetic experience is exclusively a subjective and specific to each individual, there are several types of synethesia and this variability makes it difficult to create a proper catalog of symptoms.

Synesthesia Causes

While some researchers and scientists maintain the belief that the roots of synesthesia are purely neurological, recent studies have shown that the condition is genetic, passed from parent to child. It is far more common among women than men; consequently, it is usually passed from mother to daughter.

Many scientists think that we are all born synesthetes. This is because we are born with many more brain cells than are necessary to our survival and healthy functioning. When we are about four months old, our brain cells undergo a kind of pruning process. All of the necessary brain cells remain, while the unnecessary brain cells are cast aside as the brain ages. As a result, our brains make particular connections which remain with us into adulthood. For synesthetes, this process is markedly different. Cognitive neuroscientists believe that, during the process, there is some cross-wiring in the connections which occurs. However, much of the development of synesthesia – why some people become synesthetes and others do not – remains unknown to us.

How is Synesthesia Treated?

Synesthesia cannot be considered a kind of disease. Effects might not even be recognized and the phenomenon has little to no impact on everyday life activities.

Some people even seem to think that a certain level of synesthesia can actually improve creativity and many artists seem to have taken advantage of this condition to create exceptional works of art.

People simply experience reality in a different way but they are not hindered or behave differently from the rest of the population. There are no known negative aspects connected to this condition.

Therefore, and for the fact that we know little to nothing about the causes of synesthesia, there are no treatment plans.

For researchers, it is extremely useful to work with synethetes, because these people and their experience can offer precious hints that could help us discover more details about our senses, our perception of the reality and consciousness.

Synesthesia Prevention

Because there is so little understanding in regards to what causes synesthesia, scientists and researchers remain unaware of any methods to prevent its development. However, because synesthesia is often regarded as a positive neurological condition with few negative consequences, it is very livable. Many synesthetes have reported being unable to imagine their lives without synesthesia; some people without synesthesia actively search for ways to acquire or develop synesthesia, even temporarily. Because there is no known cure, solution, or way to prevent synesthesia, if someone with synesthesia is experiencing difficulty coping with the condition, it can often prove helpful to seek therapy. Cognitive therapy may prove helpful at encouraging the synesthete to embrace and accept their condition. It may help the synesthete to discover ways to make the condition work for them, rather than against them.

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Last Reviewed:
October 11, 2016
Last Updated:
November 30, 2017