Synesthesia Psychology: What It Is And How It Manifests

Synesthesia is a condition in which a sensory experience produces a reaction that involves a different sense. But synesthesia may be more multifaceted than that, with a variety of psychological and neurological factors that may contribute to—or come as a result of—this phenomenon. 

Whether you have experienced synesthesia before or are simply curious to learn more, this article aims to provide a closer look at what synesthesia is, how it manifests, theorized mechanisms, and more. 

What is synesthesia?

Synesthesia is a condition in which an experience involving one of the five senses also produces a reaction involving a different, unrelated sense. For example, a person with synesthesia might be able to “hear” colors, “taste” words, or “feel” sounds. Those with synesthesia are referred to as “synesthetes.” 

Synesthesia is considered a relatively rare condition, with scientists estimating that it affects approximately 2% to 4% of the population. Synesthesia is not considered a mental illness and is generally harmless.

How does synesthesia manifest?

Synesthetic experiences can take many forms. Synesthetes may have either just one type of synesthesia or multiple types. A wide range of types of synesthesia have been identified, with some estimates speculating that there may be more than twenty different kinds. Below, we’ll outline some common forms of synesthesia.

Grapheme-color synesthesia

Grapheme-color synesthesia causes synesthetic associations between specific letters and numbers (or “graphemes”) and different colors. For example,, the letter X might be associated with the color yellow.

Spatial sequence synesthesia

Individuals with spatial sequence synesthesia perceive items in a sequence or ordered list as part of the physical space around them. For example, one might perceive the letters of the alphabet in a line in front of them. Depending on the person, numbers might take the form of mental imagery, or they might be physically visible.

Auditory-tactile synesthesia

This describes a synesthetic experience in which a specific sound induces a particular sensation in the body (for example, a sense of cold, warmth, or tingling in response to the sound of a door closing or rain falling). 

Mirror-touch synesthesia

Those with mirror-touch synesthesia perceive physical sensations that are happening to others as though they were happening to them. For instance, witnessing someone else’s face being touched might induce the same sensation in the face of the observer. 

Chromesthesia

Sometimes referred to as “colored hearing” or “sound-to-color synesthesia,” this form of synesthesia creates associations between specific sounds and specific colors. For example, the sound of a harp might evoke a perception of the color blue.

Number form synesthesia

This form of synesthesia causes the synesthete to experience numbers physically in the space around them. 

Lexical gustatory synesthesia

For those with this form of synesthesia, specific words induce the perception of specific tastes. For example, the word “hotel” might cause the listener to taste the flavor of apples. 

Ordinal linguistic personification

Individuals with this form of synesthesia associate different items in a sequence with different personalities and genders. 

What does the research say about synesthesia psychology?

Synesthesia is not considered a mental illness or a mental health condition.

In some instances, synesthesia develops later in life, such as in the aftermath of a brain injury or as a temporary effect of psychoactive substances (such as cannabis or hallucinogens). 

Synesthesia research is evolving, with scientists aiming to find a neurological basis for synesthetic phenomena using tools like functional magnetic resonance imaging (fMRI) and positron emission tomography (PET). Some researchers have proposed that synesthesia may come due to increased cross-communication between different brain subregions, but studies are ongoing.

Can synesthesia impact mental health?

As previously mentioned, synesthesia is generally considered non-harmful to physical health or brain function. Some synesthetes may enjoy the altered perceptions the condition induces or the chance to experience the world beyond certain cognitive and physiological constraints. 

That said, those with synesthesia may feel isolated or lonely due to experiencing the world differently than others. Other synesthetes, such as those with mirror-touch or auditory-tactile synesthesia, may sometimes find themselves experiencing distressing physical sensations. However, various resources exist that may help synesthetes tend to their well-being and mental health, ranging from support groups to mindfulness and meditation.

Therapy may also be a helpful resource for those whose synesthesia is causing them distress. In particular, cognitive behavioral therapy (CBT) has been studied for its potential to treat chronic pain and pain-related disability. This may make it an appealing option for synesthetes experiencing unpleasant sensations. 

Some people with busy schedules may struggle to commute to a therapist’s office for in-person sessions. With online therapy, you can attend sessions with a licensed therapist form the comfort of your own home. You can also message your therapist at any time, and they will respond when they’re available, which may be helpful if you’re navigating stress from synesthesia throughout the day.

Online therapy has been studied as an effective and cost-efficient alternative to in-person therapy. One study from 2017 found that online cognitive behavioral therapy (CBT) was an effective treatment for mental health conditions such as depression, anxiety, chronic pain, and more.