Synesthesia is when your brain routes sensory information through multiple unrelated senses, causing you to experience more than one sense simultaneously. Some examples include tasting words or linking colors to numbers and letters. It’s not a medical condition, and many people find it useful to help them learn and remember information.
Synesthesia is a phenomenon that causes sensory crossovers, such as tasting colors or feeling sounds. Some people describe it as having “wires crossed” in their brain because it activates two or more senses when there’s only a reason for one sense to activate.
Synesthesia isn’t a disease or a medical condition, but it can be a symptom of certain brain-related conditions.
To understand synesthesia (pronounced “sin-ess-THEE-zh-uh”), it helps to understand how your senses work. Your brain relies on your five main senses — sight, sound, smell, taste or touch — to know what’s happening around you.
That involves the following steps:
In short, your senses describe to your brain what they pick up, and your brain creates its own understanding of the world around you from those descriptions. But people with synesthesia experience the processing step differently. Their brains process the same information through two or more brain areas at once. That causes a primary and at least one secondary effect:
Visual synesthesia can also happen in different ways. Some people experience visual synesthesia like a “projection,” meaning their brain directly combines the secondary effect into their sense of sight. That causes them to experience it as if they actually see it. Other people have an “internal screen” effect. They can automatically picture it in their head but don’t experience it as if they were seeing it directly.
While you have five main senses, there are many different things you can identify with each sense. These are perception abilities. Some examples include:
Some perception abilities involve more than one sense, like balance. Your perception abilities can also involve concepts you understand using your senses, such as time, numbers and language.
Because there are so many possible combinations between your senses and perception abilities, researchers can identify at least 60 different forms of synesthesia. Some experts estimate there are more than 150 different forms. This is also why many people with synesthesia have it but don’t know what it is or that it’s unusual.
Some forms of synesthesia are better known or are more common. These include:
This form of synesthesia means that sounds cause you to feel touch-based sensations, such as temperature changes, pressure or pain.
Some people see or associate certain colors with days of the week. This is one of the more common forms of synesthesia.
“Grapheme” is the word for the smallest part of a written language, like a letter, number or symbol. Some people see different graphemes with specific colors. People who experience visual synesthesia’s projection effect often see graphemes as different colors.
Some people experience sounds related to seeing things moving. An example of this would be a person hearing a “whoosh” sound when watching something go past them.
Mirror-touch synesthesia is when you see something happen to someone else and physically feel it, too. It works similarly to the reflexive cringe you might have if you see someone trip and face-plant in front of you. However, the effect is much stronger.
Some people can watch another person being touched on the arm or hand and they also feel it. Other people can actually feel pain that others describe or pain from visible injuries. This form is more likely to be disruptive if it causes you to feel pain as a secondary effect.
Sound-color synesthesia is where you see specific colors when you hear certain sounds. It tends to be specific to certain sounds or music. Musicians and artists often describe having this form.
This is a form of synesthesia where you visualize things in a very specific way. People who have this form of synesthesia often “see” sequences with specific patterns or forms. An example of this is visualizing a calendar or a string of numbers in a certain way. Some people can mentally “map” these out in vivid or detailed ways.
Yes, synesthesia can affect people differently. Some people may only experience synesthesia under certain circumstances. Others may experience synesthesia for many reasons, or they might experience more than one secondary effect.
In severe cases, synesthesia can be strong enough to affect your ability to concentrate or focus. Fortunately, this is rare. Synesthesia is usually short-lived, so it’s usually not disruptive to this degree. People who do have it to this extent can usually learn to manage these secondary effects.
Experts don’t fully understand why synesthesia happens. But they do know there are three main types of it:
People who have developmental synesthesia are “neurodivergent.” That means their brain developed and works in a way that’s different from “neurotypical” people, whose brains developed and work as expected.
Experts can’t yet fully explain why this happens, but they suspect it may involve multiple factors:
Some people can “acquire” synesthesia because of damage to their brain. Experts suspect this type of synesthesia happens because connections within your brain can change and evolve as your brain recovers from an injury.
But some subtle differences set this type of synesthesia apart:
Nonmedical use of certain drugs, especially hallucinogens (drugs that cause pseudohallucinations and, very rarely, hallucinations), can sometimes cause synesthesia. This is especially the case at higher doses. These drugs, also known as “psychedelics,” include:
Like acquired synesthesia, there are some differences in how drug-induced synesthesia typically affects people. These include:
Developmental and acquired synesthesia don’t need treatment. In rare cases, some people may experience effects they don’t like, but they can learn to manage or minimize these effects.
Drug-induced synesthesia may happen at higher doses. That might indicate that a person needs treatment for an overdose of those drugs. However, the treatment can vary depending on the drug in question. Generally, the treatments for these are supportive, helping minimize other more serious symptoms such as seizures or agitation.
The developmental and acquired types of synesthesia aren’t preventable. The only preventable form is drug-induced synesthesia. Drugs that can cause it are illegal in many places, but there are exceptions for religious or traditional uses. Limiting your exposure to or intake of these drugs in those situations can make it less likely that you’ll experience drug-induced synesthesia.
Scientists and researchers have worked to describe and understand synesthesia since the 1800s, but skepticism about this was also very common. It wasn’t until the 1990s that imaging technologies like functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) allowed scientists to see activity in specific brain areas. Those technologies were key in confirming that synesthesia is real.
But research shows synesthesia often has a learned component. Some examples of this are learning the alphabet, counting and numbers, or the names of days and months of the year. And there’s evidence that synesthesia may be something people develop very early in life to help themselves learn and retain information.
Research also shows you can “train” yourself to have a synesthesia-like response with practice. But the effect is temporary and can fade if you don’t use it. It’s also not as fast or as strong as someone who experiences synesthesia naturally.
Synesthesia isn’t common, but it isn’t rare, either. Experts estimate at least 4% of people worldwide experience it. However, that number may be higher because there are so many possible forms of synesthesia. Some experts estimate that certain forms of synesthesia — especially time-space synesthesia — may affect as many as 1 in 8 people. It’s also possible that synesthesia is so natural for some people that they experience it and don’t realize what it is.
Experts know that some forms of synesthesia are rare, but there’s no way to know which form is rarest. A major reason for this is that many people have synesthesia and don’t know what it is or think that everyone experiences it. But the available research shows that taste- and smell-based forms of synesthesia are less common, while sight-, hearing- and touch-based forms of synesthesia are more common.
Research shows that synesthesia has benefits. People with it often have better memory abilities relating to the form of synesthesia they have. They also tend to score higher on tests that measure intelligence.
Synesthesia also has clear ties to creativity, and people with synesthesia are more likely to choose creative- or art-based careers. Sound-color synesthesia is something that many music artists have. Famous music artists with synesthesia include Beyoncé, Duke Ellington, Billy Joel and Mary J. Blige.
No, synesthesia isn’t a mental health condition. In some cases, it can be a symptom of certain medical issues, but this is rare.
Yes, synesthesia can happen in people with certain sensory problems. There are confirmed cases of synesthesia in people who developed blindness later in life and in at least one person with congenital blindness (meaning they had blindness when they were born). There’s also research on one person with synesthesia and a color vision problem who could still experience a color their eyes couldn’t actually see.
A note from Cleveland Clinic
Synesthesia is a phenomenon that causes sensory crossovers, which means you experience the world with two or more senses or perception abilities that aren’t otherwise related. Research shows synesthesia involves real differences in how your brain works, especially when it starts in childhood. It isn’t a medical condition, but it can be a symptom of certain issues when it happens after childhood.
People with synesthesia tend to be more intelligent, creative and have better memory abilities. If you think you have synesthesia, there’s no shortage of books, online communities and other resources to help you explore it. They can help you better understand the way your brain works. That’s the first step to using this ability in a way that enriches and improves your life.
Last reviewed by a Cleveland Clinic medical professional on 05/03/2023.
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