What Are The Different Types Of Synesthesia?

Medically reviewed by Melissa Guarnaccia, LCSW
Updated March 19, 2024by BetterHelp Editorial Team

If you’ve heard of synesthesia, you might know that it can involve hearing colors in response to everyday sounds. While this is a common form of experience, it’s only one of many possible manifestations of this multi-dimensional sensory phenomenon. Synesthesia can involve links between a wide range of perceptions and senses. In this article, we’ll introduce you to the many different types of synesthesia that have been identified to date and how they can impact an individual’s life.

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What is synesthesia?

A person with synesthesia experiences consistent, involuntary links between one type of stimulus and a usually unrelated type of sensory perception. In other words, there’s a kind of “overlap” or “cross-talk” between different physical sensations. To use common examples, a person with synesthesia might experience visual stimuli whenever they hear certain words or sounds, while another individual might feel like they are tasting words.

Synesthesia is a fairly common neurological phenomenon—researchers estimate that it affects roughly 2-4% of the population. As a neurological condition, each form of synesthesia, such as hearing motion synesthesia, personification synesthesia, or associative synesthesia are relatively harmless both to those it affects and the general population. Vladimir Nabokov, a famous 20th-century author, is an example of a well-known synesthete.

In theory, a person with synesthesia may experience synesthetic associations between any two kinds of perception. Common forms of sensory connections include viewing letters or numbers in different colors such as colored music sheets, feeling sensations of touch in response to sounds, or picturing sequences of numbers as a mental map. While researchers are beginning to discover the vast diversity of this experience, what synesthesia means and its causes are still not fully understood. However, authors of the published report, Mechanisms of Synesthesia: Cognitive and Physiological Constraints posit that there is a neurobiological cause for the phenomenon. 

The associations that people with synesthesia (called synesthetes) experience are often highly stable over time. A synesthete who perceives the letter H as rough and sandpapery and the letter P as rubbery and flexible may experience those associations throughout their entire lifespan. This is not always the case, though; a 2012 paper reported that as many as 17% of synesthetes might see changes in the type, frequency, or intensity of how they experience synesthesia over time. This could mean that synesthetes that experience colored hearing, associating certain letters and numbers with certain colors, may then develop a new association later in life.

While this can be a difficult phenomenon to verify, researchers have developed a synesthesia test that seems to reliably distinguish between people with and without synesthesia. Synesthesia tests often rely on experimental findings that synesthesia can impact the speed at which people recognize certain patterns or make perceptual judgments. For instance, someone who perceives different numbers as different colors might have an easier time spotting 2s mixed in with similar-looking 5s—the “out-of-place” numbers may stand out as clearly as blobs of orange in a field of blue. If you’re interested in finding out more about whether you might have synesthesia, you can test yourself online using the standardized Synesthesia Battery. You can read on for additional information and resources on this medical condition.

Synesthesia can take many forms

Synesthesia is thought to manifest differently in different people. Although two individuals might experience tastes in response to sounds, one may link the musical notes like C# with a lemony flavor while the other has the synesthetic perception of vanilla. 

That said, certain broad categories of association may be more common than others. For example, synesthesia research has found that synesthetes are more likely to link sweet and sour tastes with high-pitched sounds and bitter or savory tastes with lower pitches. This suggests that at least some kinds of synesthesia may be amplifications or modifications of mental associations that are present at low levels in most people.

People with synesthesia can be classified as projectors or associators. Projector synesthetes report vivid sensory effects that appear to exist in space rather than in their minds. For example, if they are looking at the page of a book, they might be perceiving letters as highlighted in different colors.

Associators may not have such strong external perceptions. Instead, they might have strong mental links between particular sensations or concepts. An associator synesthete might think of the idea of Wednesday as fuzzy and friendly, but they wouldn’t actually feel its hair brushing against them when looking at that day on a calendar. A 2005 overview of individual differences in synesthesia estimated that most synesthetes are associators while only about 10% of synesthetes are projectors.

What are the known types?

Just how many kinds of synesthesia are there? In one sense, you could say that the number is incalculable, since it’s rare for two people to have exactly the same synesthetic experiences. However, researchers often categorize distinct types of synesthesia based on how various sensory or cognitive processes overlap. Research suggests that there are up to 73 different kinds of synesthesia. The following list of synesthesia types helps illustrate the immense diversity within this mental phenomenon.

Grapheme Color Synesthesia

Grapheme synesthesia, or grapheme color synesthesia, is considered one of the most common types of synesthesia, present in around 1-2% of the population. It involves a link between individual letters or numbers and particular colors, so that L might look green while 5 may appear red. People with grapheme-color synesthesia often report that the colored letters help them memorize complex words or strings of numbers.

In some cases, a person with this type of synesthesia will see each letter of a word in a distinct hue, while others might find that entire words take on the color of the first letter. This latter type is considered by some to be a separate kind of synesthesia known as lexical-color synesthesia, although others group it with grapheme color.


People with this type of synesthesia report that they experience numbers within a kind of mental shape or diagram. When they think about numbers, they may consistently see specific values at particular points within this imagined structure. These forms don’t always follow an obvious logic, but they may still enhance performance on certain mathematical tasks.

Lexical-gustatory synesthesia

This is thought to be an especially rare form of synesthesia. Lexical gustatory synesthetes experience tastes in association with words. In some cases, every single word that the individual hears, speaks, reads, or thinks about induces a different taste that makes sense to them. Reported flavors vary and have included onions, oranges, and canned peas. A vision taste association example would be the word “strong” tasting like a melon.

Spatial sequence synesthesia (SSS)

This type of synesthesia involves items in an ordered list appearing to occupy positions in space. For example, certain months might seem closer or farther away depending on where they fall in the year. Other people might experience the hours of the day in a clock-like arrangement around their bodies. Number-form synesthesia may be just one type of SSS that relates specifically to numerical sequences.


This is the technical term for seeing sounds as colors, sometimes with accompanying shapes or motions. These visual color elements typically accompany the sounds rather than replacing them, and people with this type of perception often find that it enriches the experience of listening to music. Many notable contemporary artists have claimed that they have chromesthesia, and that it’s helped them in their creative work. There are also some synesthetes where sounds kind of take the form of colors.


When people with mirror-touch synesthesia see another person receiving physical contact, they may feel as though they’re the one being touched. This perception can be stronger or fainter in different individuals, though the intensity is often related to what kind of object is touching the other person. 
Research in human neuroscience that focuses on mirror neurons suggests that there may be a link between this type of synesthesia and high levels of empathy, reinforcing the notion that the capacity to feel other people’s pain might be linked to our ability to imagine ourselves in their place.


Some people with synesthesia see a scrolling string of words underneath others while they talk. Others observe their own thoughts appearing in the air in front of them. This is known as tickertaping, and it’s one of the first forms of synesthesia described in the scientific literature. It may accompany grapheme-color synesthesia, with letters appearing in corresponding colors.

Ordinal-linguistic personification (OLP)

Like spatial-sequence synesthesia, OLP affects the perception of items in lists or sequences. But rather than locations in space, they’re perceived as people, possessing distinct personality traits and sometimes genders. This can involve fairly detailed ideas—one researcher interviewed an individual who perceived the letter I as “honest and well-intentioned, but dictatorial and overbearing”.

Auditory tactile synesthesia

In this form of synesthesia, specific sounds can produce tactile sensations in various parts of the hearer’s body. Different types of music might provoke different levels of pressure, or some spoken words might feel prickly while others seem smooth or soft. 

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In some cases, this can be unpleasant, with some individuals reporting that certain songs or voice qualities produce uncomfortable sensations. Others may find their synesthetic responses enjoyable. There’s evidence that the phenomenon of autonomous sensory meridian response (ASMR)—in which certain sounds produce a pleasant tingling sensation in some people—might be linked to auditory-tactile synesthesia.

How online therapy can help

Synesthesia is not considered a mental disorder, but it may be more common in people with conditions like post-traumatic stress disorder and anxiety disorders. Studies show that online therapy can help those who are experiencing such disorders with associations between the five senses, along with a range of other mental health challenges. In a meta-analysis of over 90 studies, with almost 10,000 total participants, researchers found that online therapy was as effective as face-to-face treatment, specifically mentioning its efficacy when addressing post-traumatic stress disorder and anxiety disorders.

If you’re experiencing unusual sensations that are causing you distress, or if you find that synesthetic experiences are making it difficult for you to relate to others, you might want to talk with a mental health professiona to gain a better understanding of your condition and gene expression. Online therapy platforms like BetterHelp can make it quick and easy to connect with a therapist who has relevant experience or training in challenges that may be associated with synesthesia. Many clients also find that receiving different methods of counseling remotely is more convenient since it can take place anywhere with an internet connection. A therapist can support you online whether your experiencing a condition like motion synesthesia or mirror-touch synesthesia, or want to learn more.


Synesthesia comes in a variety of forms and may involve connections between many types of sensory and cognitive processes. Associations of colors with sounds, numbers, or letters appear to be particularly common. However, many synesthetes also report links between perceptions of space, time, touch, taste, and smell, or they may connect impressions of human personality with particular sensations.Research indicates that every person with synesthesia experiences it in a slightly different way. If you’d like to learn more about how you perceive and interpret the world around you, consider getting matched with a licensed therapist online. Working with a mental health professional can be a productive step toward emotional and cognitive wellness.
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