What Happens During A Synesthesia Test?

Medically reviewed by Aaron Dutil, LMHC, LPC
Updated April 26, 2024by BetterHelp Editorial Team

What does the color blue sound like? Can you taste certain songs? Does the number one smell like fruit? These may seem like strange questions—unless you’re taking a test for synesthesia. People who have this unique trait may experience uncommon sensory associations like these. There are several different ways in which synesthesia can manifest, and a few different ways to test for it.

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What is synesthesia?

Synesthesia is a neurological trait that enables synesthetes to experience involuntary, automatic sensory perceptions from the stimulation of a different sense. For example, an individual may perceive things such as different colors when hearing words or smells when listening to music. There are other types of synesthesia, and the nature of the condition varies among individuals. One synesthete might associate the number twelve with blue, while another could claim that the color blue tastes bitter.

While this experience may seem peculiar to non-synesthetes, it is not considered a disorder or mental illness and generally doesn't have a negative impact on a person's functioning. The cause of synesthesia remains uncertain, though researchers believe it is more common among people with autism or those who are particularly artistic or creative. Family history may also play a role in its development. Synesthesia can emerge later in life due to psychedelic drug use or as a consequence of specific brain injuries.

Different types of synesthesia

The way people experience synesthesia varies widely. That said, it can generally be classified into two broad categories: projective and associative.

Projective synesthesia

People who have projective synesthesia may taste, smell, feel, see, or hear certain things as a result of a stimulus that typically triggers a different sense. For instance, someone with projective synesthesia may smell fresh cut grass when they hear a certain song. Another example would be someone who can taste certain words. For example, when they hear the word “bubbles”, they might immediately experience the flavor of vanilla icing on their tongue.

Another way to think about it is that people with projective synesthesia have two sensory responses when only one sense is stimulated, such as hearing colors or seeing scents. Note, however, that this is just a general classification, and that there are over 100 different manifestations of projective synesthesia.

Associative synesthesia

In contrast to projective synesthesia, those with associative synesthesia do not physically experience the additional sensations that are linked to a sensory perception. Instead, they simply feel a strong association. For example, a person might consistently associate the number 15 with the color green, even though they don’t actually see it as green when it’s written down. To these synesthetes, there’s a connection between the stimulation and the sense that’s activated, even if it cannot be seen, felt, heard, tasted, or explained.

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Types of synesthesia tests

Some experts believe that synesthesia only affects about .05% of the population, but estimates vary quite widely. The problem with assigning a percentage to the rate of people who experience synesthesia is that it can be difficult to test for this trait. Many people may not even realize they experience the world differently than others do—either because the response is so natural and has been happening through the course of their entire life or because their experience of it is mild. That said, those who suspect they may have synesthesia can take any of a few different types of tests to see if they do.

Note that a synesthesia test is generally not considered to be an exact science or clinically reliable. However, they can be a helpful place to start for those who believe they may have one form or another of synesthesia.

The synesthesia battery

The Synesthesia Battery can test for various types of synesthesia. It takes the form of an online questionnaire with about 80 questions, depending on your answers as you go. The test is fairly simple and can be completed in about 15 minutes. The questions are mostly sliding scale or multiple choice, and you’ll need to register with the website in order to get your results. 

Grapheme color consistency test

This test is for the most common form of synesthesia, which is where a person experiences or associates colors with numbers or letters. The grapheme-color synesthesia consistency test can take different forms, ranging from a simple, five-minute, 20-question quiz to a lengthy and detailed questionnaire that could take you up to an hour to complete. The questions mainly relate to what colors you perceive when you see certain numbers or letters. You’ll be shown a number or letter, and you can move the indicator to make its color match how you see or experience it.

Color consistency test

Another measure that may help you discover whether you have synesthesia is a consistency test. It’s a computerized test that shows the participant all 26 letters of the alphabet and the numbers zero through nine next to a palette of 13 colors. Similar to the grapheme-color consistency test discussed above, the participant will be asked to choose the color they associate with each letter and number. They’ll do this three times, with the choices randomly disarranged each time. This is because the associations of true synesthesia must be automatic and consistent over time.

What to do with your results

Again, synesthesia is not classified as a mental health disorder, and it may cause a person few or no challenges with day-to-day functioning. If your results from any of these tests indicate you may have synesthesia and you're not experiencing any adverse effects, you can simply enjoy your unique way of viewing the world. 

However, some synesthetes may have trouble with sensory overload in highly stimulating environments. Others may even have lower self-esteem if they’re made to feel bothered when they impart their sensory perception style with non-synesthetes. If you’re facing challenges like these, it may be helpful to meet with a therapist. They can create a space where you can process your experience and your feelings about it, and they can help you build self-esteem and learn coping mechanisms for sensory overload.

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Online therapy can help with synesthesia

Research suggests that both in-person and online therapy can offer similar benefits to clients in most cases. If you’d prefer to meet with someone in a physical office, you can search for a provider in your area. If you’d prefer to meet with someone virtually from the comfort of your own home, you might consider an online therapy platform like BetterHelp. You can get matched with a licensed therapist who you can meet with via phone, video call, and/or online chat to discuss the issues you may be facing.


It may be challenging to diagnose synesthesia, but online tests focused on senses can provide insights into whether you possess this unique way of perceiving the world. If tests or other methods indicate you may have synesthesia and you're struggling to cope, decide whether meeting with a therapist could be helpful. For those who are merely curious or you wonder about synesthesia, engaging in fun activities and writing about your experiences can offer valuable understanding.
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