Types Of Synesthesia
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.
What is synesthesia?
How does synesthesia relate to perception and senses?
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 synesthesia.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.
Synesthesia and taste
That said, certain broad categories of synesthetic 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.
Projectors vs associators
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?
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.
Number-form synesthesia
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 spatial sequence synesthesia that relates specifically to numerical sequences.
Chromesthesia synesthesia
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.
Mirror touch synesthesia
Tickertape synesthesia
OLP synesthesia
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.
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 with associations between the five senses
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.
Takeaway
Frequently asked questions
Read more below for answers to questions commonly asked about this topic.
How many types of synesthesia exist?
Currently, over 80 kinds of synesthetic experiences are described by brain scientists. These range from perceiving letters as different colors to associating various visual stimuli with sensations in the body. All five senses are involved in the many synesthetic experiences described so far. However, as research continues, a better understanding might lead to even more experiences being classified.
Besides lexical gustatory (taste), color synesthesia, and mirror touch synesthesia, what are the other common types?
Grapheme color is the most common form where a person sees colored letters or words when hearing or seeing text. Interestingly, many bilingual and multilingual people only have experience with particular languages. For example, a French Greek-speaking king person may only see colors when hearing French words but not when hearing the same Greek words.
Chromesthesia is also a common form of this neurological condition where colors and music are connected. For example, some contemporary artists like the painter Wassily Kandinsky created abstract paintings showing how he associated particular musical notes with certain colors.
What's the associative type of synesthesia?
Associative synesthesia is where the person feels a strong connection between something they experience in one of the five senses and another type of perception. For example, a person hears the C note on the piano and then sees the color green.
What is personification synesthesia?
This variation is where a person perceives ordered sequences like days of the month as personalities or genders. An example would be experiencing Wednesdays as a male or the 3rd of the month as an angry person.
For other examples of questions that might be beneficial to explore in therapy, please see below.
What is the rarest type of synesthesia?
What is kinesthetic?
What are the concepts of it?
Does it impact genders differently?
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