Synesthesia facts for kids

Quick facts for kids Synesthesia
A person experiencing synesthesia may associate certain letters and numbers with certain colors.
Classification and external resources
Pronunciation	/ˌsɪn.əsˈθiː.zi.ə/
Specialty	Neuroscience, neurology, psychology
Patient UK	Synesthesia

Synesthesia is a fascinating way some people experience the world. It's when stimulating one sense automatically and involuntarily triggers an experience in another sense. Imagine hearing a sound and seeing a color, or tasting a word! People who experience this are called synesthetes.

Synesthesia can connect any of our senses, like sight, sound, taste, touch, and smell. It can also link to other perceptions, such as feeling pain or sensing time. Each synesthete's experience is unique, shaped by their life and the specific type of synesthesia they have. For example, some people see letters or numbers as having their own special colors. Others might see numbers, months, or days of the week in specific places in space, like a mental map.

Scientists don't fully understand how synesthesia develops. It's thought to begin in childhood when kids first learn about abstract ideas like letters and numbers. The word "synesthesia" comes from ancient Greek words meaning "together" and "sensation." The first recorded mention of something like synesthesia was in 1690 by John Locke, who wrote about a blind man who said he saw scarlet when he heard a trumpet.

What is Synesthesia?

Synesthesia is a special way the brain connects different senses. It's not a choice; these connections happen automatically. For example, a synesthete might always see the letter 'A' as red, or hear a specific musical note and always taste chocolate. These experiences are very real to the person having them.

There are two main ways synesthesia can show up:

• Projective synesthesia: This is when you actually "see" or "feel" something outside your body. For instance, hearing a trumpet might make you see an orange triangle floating in the air.
• Associative synesthesia: This is when you feel a strong, automatic connection between a trigger and a sense. You might hear a trumpet and just know it sounds "orange," even if you don't physically see the color.

Synesthesia can link almost any two senses or ways of thinking. We describe different types using a simple format: "trigger → experience." So, if letters and numbers (called graphemes) make you see colors, it's called grapheme–color synesthesia. If music makes you see colors and movement, it's music → (color, movement) synesthesia.

Different Kinds of Synesthesia

While there are many possible combinations, some types of synesthesia are more common than others.

Seeing Colors with Letters and Numbers (Grapheme-Color Synesthesia)

From the 2009 non-fiction book Wednesday Is Indigo Blue

This is one of the most common forms. People with grapheme-color synesthesia see individual letters and numbers as having their own specific colors. For example, 'A' might always be red, and 'S' might always be yellow. While everyone's colors are unique, some letters tend to be seen with similar colors by many synesthetes.

Hearing Colors (Chromesthesia)

Another common type is when sounds are linked to colors. For some, everyday sounds like a dog barking can trigger a color. For others, specific musical notes or keys create a burst of color. These visual experiences, like seeing colors from sounds, are called photisms. Some musicians with this type of synesthesia might even have perfect pitch because seeing and hearing colors helps them identify notes.

Tasting Words (Lexical-Gustatory Synesthesia)

This rare form of synesthesia means certain words trigger specific tastes. Imagine hearing the word "basketball" and tasting waffles! It's a very unusual experience, but it's very real for those who have it.

Feeling What Others Feel (Mirror-Touch Synesthesia)

People with mirror-touch synesthesia feel a similar sensation to what they see another person experiencing. If they see someone being tapped on the shoulder, they might feel a tap on their own shoulder. Some studies suggest people with this type of synesthesia might have higher levels of empathy.

Seeing Numbers in Space (Number Form Synesthesia)

A number form from one of Francis Galton's subjects (1881). Note how the first 4 digits roughly correspond to their positions on a clock face.

A number form is like a mental map of numbers that appears automatically when someone thinks of numbers. These numbers might show up in different places in space, and the map is different for each person. This was first described in 1881.

Giving Personalities to Days and Letters (Ordinal Linguistic Personification)

In this type, ordered sequences like numbers, days of the week, months, or letters of the alphabet are linked with personalities or genders. For example, Tuesday might feel like a grumpy old man, or the letter 'A' might seem like a kind girl.

Other Interesting Types

• Auditory–tactile synesthesia: Certain sounds can cause physical sensations on the body. Hearing a specific word might feel like a touch on your arm.
• Spatial sequence synesthesia: People see ordered sequences, like dates or months, as points in space around them. They often have excellent memories.
• Ticker-tape synesthesia: When people hear words, they mentally see them written out, sometimes like words on a scrolling ticker. This might help researchers understand conditions like dyslexia.
• Emotional synesthesia: Emotions can trigger responses in other senses, like a certain feeling causing a specific smell or color.

There are at least 80 known types of synesthesia, and scientists are always learning more! For example, researchers are looking into whether ASMR (Autonomous Sensory Meridian Response), which is a tingling sensation some people feel in response to certain sounds or sights, might be a form of synesthesia.

Is Synesthesia a Medical Condition?

Many synesthetes don't realize their experiences are unusual until they talk to others. Since these perceptions are automatic and consistent, they just seem normal. Most synesthetes find their experiences pleasant or neutral. Very rarely, it can lead to too much sensory input, which can be overwhelming.

Synesthesia is not considered a medical condition or a disorder. It usually doesn't cause problems in daily life. In fact, many synesthetes see it as a special gift, like an extra sense they wouldn't want to lose. They often discover their unique perception in childhood. Some even use their synesthesia to help them with things like memorizing names, doing math, or creating art and music.

Synesthetes are often very creative. Their unique way of seeing the world can give them a memory advantage. For example, someone who sees sequences in space can easily recall past events by simply "looking" at their mental visualization.

How Do We Know Someone Has Synesthesia?

Reaction times for answers that are congruent with a synesthete's automatic colors are shorter than those whose answers are incongruent.

To confirm if someone has synesthesia, scientists look for consistency. If a synesthete says 'A' is red today, they should say 'A' is red years from now. Tests show that synesthetes are about 90% consistent with their associations, even over long periods. People without synesthesia, if asked to make up associations, are only 30-40% consistent.

There are specific tests for different types of synesthesia. For grapheme-color synesthesia, a person might be shown black letters and numbers and asked to name the colors they see. For chromesthesia, sounds might be played, and the person describes the colors or shapes they experience. The key is that these associations are permanent and automatic, not just memories.

The automaticity of synesthetic experience. A synesthete might perceive the left panel like the panel on the right.

Neurologist Richard Cytowic identified some key features of synesthesia:

• It's involuntary and automatic.
• Perceptions often feel like they have a "location" in space.
• The experiences are consistent and simple, not like detailed pictures.
• They are very memorable.
• They come with a strong feeling or emotion.

A Look Back: The History of Synesthesia

Interest in how senses connect goes way back to ancient Greece. People wondered if music had a "color" quality, like its pitch or length. The idea of describing music as "colored" became common. Later, scientists like Isaac Newton and Goethe thought musical tones and colors might share common frequencies. There's a long history of people trying to build "color organs" to play colored music.

The first medical description of "colored hearing" was in 1812. In the late 1800s, scientists like Gustav Fechner and Francis Galton started studying synesthesia more formally. However, for much of the 20th century, studying subjective experiences like synesthesia wasn't popular in science.

In the 1980s, scientists became interested again. Researchers like Larry Marks, Richard Cytowic, Simon Baron-Cohen, and Jeffrey Alan Gray began exploring how real and consistent synesthetic experiences were. Today, synesthesia is a popular topic in scientific books, films, and even novels. With the rise of the internet, synesthetes around the world have connected and formed communities.

Synesthesia in Art and Everyday Life

Synesthesia has inspired many artists, musicians, and writers. It gives them a unique perspective that they often share through their work.

Famous People with Synesthesia

Many famous people have experienced synesthesia.

• Solomon Shereshevsky, a Russian newspaper reporter, had a rare form where words and text were linked to vivid images, sounds, tastes, colors, and sensations. This made it hard for him to understand abstract ideas because every detail was so strong.
• Neuroscientist V. S. Ramachandran studied a synesthete who was colorblind but could still "see" colors for letters in his mind, even colors he couldn't see with his eyes.
• The rapper and producer Kanye West has described seeing sounds, saying that everything he creates musically is like a painting.
• Musicians like Billy Joel, Lorde, Billie Eilish, Charli XCX, Brendon Urie, and Pharrell Williams have also spoken about their synesthetic experiences. Pharrell even named an album Seeing Sounds.

Synesthesia in Creative Arts

Music, Pink and Blue No. 2 (1918), Georgia O'Keeffe

• Writers: Vladimir Nabokov wrote about his grapheme-color synesthesia in his memoir, Speak, Memory, describing how letters had specific colors and textures for him. Joanne Harris, author of Chocolat, experiences colors as scents.
• Painters and photographers: Artists like Wassily Kandinsky (a synesthete) and Georgia O'Keeffe explored connections between images and music in their paintings. Contemporary artists like Carol Steen and Marcia Smilack use their synesthesia to create unique artwork.
• Composers: Mikalojus Konstantinas Čiurlionis, a Lithuanian artist, saw colors and music at the same time, naming many of his paintings after musical pieces. Alexander Scriabin and Olivier Messiaen composed music with deliberate color associations. Modern composers like Ramin Djawadi, known for Game of Thrones, also associate colors with music.

Synesthesia in Books and Movies

Synesthesia is sometimes used in stories to develop characters or as a plot device.

• In books like The Gift by Vladimir Nabokov, synesthesia shows how characters experience the world in a unique way.
• The 2024 Canadian film Magnetosphere features a 13-year-old girl with synesthesia.
• The Colors Within, also from 2024, is about a high-school student who sees colors for people.

Exploring Synesthesia Further

Tests like this demonstrate that people do not attach sounds to visual shapes arbitrarily. When people are given a choice between the words "Bouba" and "Kiki", the left shape is almost always called "Kiki" while the right is called "Bouba".

Studying synesthesia helps us understand how our brains combine information from different senses. One interesting example is the bouba/kiki effect. In a famous experiment, people are shown two shapes, one spiky and one rounded. Almost everyone agrees the spiky shape is "Kiki" and the rounded one is "Bouba." This shows that our brains naturally link sounds to visual shapes.

Researchers hope that learning more about synesthesia will help us understand consciousness itself. It's a unique window into how our minds create our experiences of the world.

Technological Applications

Synesthesia has even inspired technology!

• The vOICe: This device helps visually impaired people "see" with their ears. A camera captures images, and the vOICe converts them into sounds. Higher objects become higher pitches, and brighter areas become louder sounds. This allows users to create a mental picture of their surroundings using sound.

See also

In Spanish: Sinestesia para niños