How Does Chromesthesia Affect The Brain?

Have you ever been to a concert and felt how colorful lights and visual effects heighten your experience of the music? For people with chromesthesia, even everyday sonic experiences can lead to an explosion of vivid colors and intense sensory stimulation. 

Chromesthesia is caused by complex processes in the brain, and its effects can influence how a person experiences the world. Here, we will explore chromesthesia’s effects on the brain and dive into the research on its causes, origins, and implications for mental well-being.

Chromesthesia: Understanding sound-color synesthesia

Chromesthesia, also known as sound-color synesthesia, is the most common form of synesthesia, where individuals perceive specific colors in response to different sounds. Chromesthesia is not a disorder, but rather a neurological condition produced by unusual connections between different parts of the brain.

The effect of these structural differences may manifest in a unique sensory experience that intertwines auditory and visual stimuli. Imagine hearing a guitar strum and seeing vibrant waves of blue or listening to a piano note and witnessing a burst of yellow. For individuals with chromesthesia, these synesthetic experiences are a natural part of their inner world. 

Projective vs. associative chromesthesia

Understanding how chromesthesia affects the brain can provide insight into the intricate workings of human cognition and sensory processing. There are two distinct forms of chromesthesia—projective and associative. Projective chromesthetes perceive colors as if they are externally projected onto the surrounding environment, while associative chromesthetes experience the synesthetic colors internally, typically as mental associations or overlays onto the perceived sounds.

What do people with chromesthesia see?

Chromesthetic experiences vary widely between individuals and may be triggered by any number of auditory stimuli, such as musical notes, spoken words, environmental sounds, or even specific voices.

Some research has found that the nature of the sound tends to affect the synesthetic experience in predictable ways. High pitched sounds, for example, tend to produce a brighter or more vibrant experience, whereas low-pitched colors may be more muted and dull. Here are some examples of sensory experiences that chromesthetes may have:

• An individual may consistently associate the C note with a bright red hue while low E may be golden and shimmery.
• The sound of a deep voice may evoke a dark brown bubble-like form while a higher-pitched voice may appear light yellow and have sharper edges.
• A person at a concert may experience a colorful display of visuals that includes different colors, shapes, and opacity.
• A dog’s bark may produce dark spots or flecks in a chromesthete’s field of vision.

What causes synesthetic experiences in the brain?

The exact cause of synesthetic experiences, including chromesthesia, is still a subject of ongoing research. Studies suggest that it may be related to an atypical cross-wiring of the brain’s sensory regions. Typically, each region of the brain’s sensory cortex processes the different senses. In individuals with chromesthesia, these regions appear to be interconnected, which allows sensory information from one sense to activate regions associated with another. This cross-activation leads to unique sensory experiences. 

Another theory proposes that certain connections in the brain are usually inhibited but become disinhibited in synesthetes. This allows sensory pathways to activate at the same time, leading to cross-sensory experiences. Called disinhibition of feedback, this theory assumes that adjacent brain areas are always connected but usually inhibited. This explanation helps us understand why synesthesia occurs.

There is also some evidence to suggest that the neurotransmitter serotonin may play a role in synesthetic experiences. Some studies have found that certain drugs that affect serotonin levels can induce or stop synesthetic experiences. These drugs may include hallucinogenic drugs that stimulate serotonin receptors as well as pharmaceuticals that suppress it. 

How chromesthesia develops

Like other forms of synesthesia, chromesthesia typically develops early in life when the brain is still developing. Scientists believe that a combination of genetic, neurological, and environmental factors may contribute to its development.

Genetics and neurology

Research suggests that chromosthesia is influenced by as many as 37 genes, some related to the development of the brain. More specifically, researchers believe that synesthesia occurs when certain areas of the brain are not properly separated during brain development, resulting in additional neural (nerve cell) connections.

Early learning

In addition to sensory experiences, conceptual information about sound and music may play a role in how chromesthesia develops. Some of these associations may develop as a result of a person’s art or music education. Different hues are often associated with certain emotions in early learning experiences. 

Sadness, for example, is commonly depicted in darker hues. At the same time, low, somber notes tend to be associated with sad songs. This may influence the association of darker musical notes with darker colors for the synesthete.

Is chromesthesia a brain disorder?

Chromesthesia is not considered a medical condition or disorder, but rather a form of neurodivergence. Neurodivergent traits are variations in human neurology that are different from the typical or average neurotypical population. Though chromesthesia may significantly influence a person’s experience of the world, it is generally not associated with any negative health consequences. In fact, many individuals with chromesthesia embrace their unique sensory perceptions as a source of inspiration and creativity. 

However, chromesthesia is involuntary, and there may be instances in which it interferes with a person’s ability to function normally. For example, individuals with chromesthesia and other sensory processing differences may find loud or noisy environments overwhelming. Their experiences may be more vivid or emotionally impactful due to the additional sensory stimulation. 

Chromesthesia and mental health

These vivid sensory experiences may be one reason sound-color synesthesia has been found to be a risk factor for posttraumatic stress disorder (PTSD). Additionally, synesthesia in children has been linked to higher rates of anxiety disorder. Thus, while chromesthesia is not itself a disorder, there may be some instances in which sensory issues influence mental well-being. 

In such cases, the intervention of a mental health professional may be beneficial. Though chromesthesia cannot be treated, a therapist can help individuals treat any mental health issues that may co-occur with synesthesia. In therapy, individuals may learn self-soothing techniques or coping strategies for navigating overwhelming situations. Talk therapy can be helpful for managing a wide range of mental and emotional issues, and has been found to be valuable for three-quarters of those who enter.

Those with sensory differences may find online therapy to be especially helpful. Online therapy platforms like BetterHelp can make it easy to attend therapy from the comfort of home, which may be advantageous when in-person appointments feel overstimulating. 

While there is currently no research showing the efficacy of online therapy for coping with chromesthesia and other forms of synesthesia, research does show that online therapy may be just as effective as in-person therapy for treating many different mental health conditions, including anxiety and depression.