Synesthesia: The 6th Sense

“I often think in music. I live my daydreams in music. I see my life in terms of music... I get the most joy in life out of music."

These are the words of one Albert Einstein. His love for music is well-documented - there are many pictures of him indulging himself in the tunes of his violin, seemingly oblivious to the rest of the world. As anyone who has ever loved music would know, our musical tastes have a lot to do with what we think, and who we are. Of course, on first read, Einstein’s account sounds nothing more than a metaphor for visualization. But, could it be more? Could someone possibly “see” music? Could there be anything more to the conscious experience? 

In 1812, a physician by the name of Georg Tobias Ludwig Sachs was writing about the nature of albinism, having had the condition himself. Color was a recurring topic in his analysis of albinism and as such, in discussing his own experience, he mentioned that “colored ideas” appeared to him. They were “intimate and recurring” and couldn’t be “reckoned with usual sight,” according to Sachs. Sachs is now regarded as the first medically documented case of Synesthesia, a neurological condition in which a sensation in one of the senses evokes a sensation in another. The term quite literally means a “cross-mingling” of the senses, exactly opposite to the more familiar word “anesthesia,” which means “no sensation.” 

This cross-mingling could theoretically happen between any 2, or even more, senses. It’s no wonder, then, that there are more than 80 types of synesthesia known till now. Sach himself seemingly had multiple forms of synesthesia, reporting that “numbers, days of the week, time periods, letters, notes of music: all of these elements adopt those colors. These introduce themselves to the mind as if a series of visible objects in dark space, formless and noticeably of different colors.” This is most likely a case of ordinal linguistic personification, where, as the name suggests, ordered sequences tend to have personalities and colors to each element of the sequence. This type of synesthesia tends to co-occur with grapheme-color synesthesia, the most common form of synesthesia where numbers are associated with colors. 

There are many other types of synesthesia such as lexical gustatory-synesthesia, where hearing certain words causes certain tastes, or audio-tactile synesthesia where hearing certain sounds can lead to the sensation of touch in parts of the body. Oddly enough, there’s even a type of synesthesia where swimmers thinking, watching, or performing a certain swimming stroke, perceive a color that they consistently associate with that swimming stroke. There have also been surgeons with what’s called “mirror-touch” synesthesia where they were able to feel the pain of the patients they were observing while CPR was being administered. “I have died many times,” says Dr. Joel Salinas, a neurologist who possesses this condition. However, the most awe-inspiring case of synesthesia probably took place when a man was able to visualize colors when he saw numbers. The only catch is... he was colorblind, and the colors he was visualizing he had never even seen.

But, how credible are these accounts? Considering Sach’s colorful landscape was also attributed by some to congenital eye-defects common in people with albinism, couldn’t all these just be hallucinations or simply psychedelic experiences under the influence of a drug or some other sign of an overreaction? 

The science is very clear on that front. While “synesthesia-like” experiences have been created with the help of psychedelic drugs, synesthesia is a consistently reproduced condition - meaning those that have it recall the same exact colors, the same exact tastes, the same exact sensations with ninety plus percent accuracy, even when they are tested years apart and without warning. This pattern of consistent experiences has so far been the most reliable way to test whether someone has synesthesia or not. Mind you, consistency here does not mean that the same letter will always be correlated with the same color for all synesthetes, people who have synesthesia. Individual to individual these correlations vary, even if they have the same type of synesthesia, but for the same individual, the correlation stays remarkably precise, so precise, in fact, that they can tell apart shades of color that are only slightly different. So if the letter “a” is an orangish-red for you, it may not be the same for another synesthete. But it will always be orangish-red for you. This quality is also why the musical synesthetes tend to have perfect pitch because they can superimpose the sound with a very intricate visual map and confirm what is what. 

Synesthetes also score higher on memory tests, especially with numbers and names because they are remembered as multi-property objects, each with unique associations. Perhaps the most compelling evidence that synesthesia is not an occasional, random hallucination is the fact that the brains of synesthetes are physically different from those that are not. Synesthetes display consistently higher connectivity in their brains than non-synesthetes, especially in between visual and auditory regions. The visual regions were also better connected to the frontoparietal region, a region crucial for color association with numbers or letters. The amount of connectedness also reflected the strength of the synesthetic experience: the stronger the connections, the stronger the synesthetic experiences. Research has also revealed that synesthetes generally have more white matter. This intrinsic, increased network connectivity led scientists to agree that there is a genetic component to synesthesia. Sure enough “About 40 percent of synesthetes have a first-degree relative with synesthesia, and many synesthetes recall having synesthesia as long as they can remember.“

An interesting way to test whether you might have grapheme-color synesthesia, which is the number to color synesthesia, is to look at this picture: try to identify the 2s as quickly as you can. People who have synesthesia react quicker on a test like this because the 2s and 5s are naturally seen in different colors to them like this, which makes it much easier to identify. They are able to see the 2s in different colors without necessarily having to “hunt” for them like non-synesthetes. So they are not staring at a number and then thinking of the associated color; it’s an automatic response, one synesthetes can’t turn off. 

And that can be a problem, right? Even with the 5 senses most of us are able to use, sometimes we feel overwhelmed by the world around us. So to be over-stimulated all the time with a barrage of sensory inputs would be pretty uncomfortable- 

…or so you would think. 

Synesthetes, by and large, consider their abilities as gifts rather than curses. Most synesthetes are completely unaware that others don’t see the world as they do. For some, sound has always had color, color has always had taste, and taste has always had sound. It sounds strange, but you’d be surprised how many of your favorite artists are synesthetes. From musicians like Lorde, and Pharell Williams to novelists like Vladimir Nabokov, from theoretical physicists like Richard Feynman to painters like Vincent Van Gogh - all are said to have had synesthesia, their conditions as versatile as their crafts. Common amongst all, however, is the fact that their contributions have all been incredible feats of creativity. This convergence of creativity and synesthesia is no coincidence. In fact, synesthesia is up to seven times more common in artists and people involved in creative professions. It’s no surprise then that Synesthetes perform better on tests of creativity and originality than the average person. 

But, of course, as with any condition, it’s not all sunshine and rainbows. Some kids who have the condition display poorer reading comprehension than their peers and often have a hard time following lectures. Solomon Shereshevsky was a Russian Journalist who was also diagnosed with the condition. He could recall unusually long lists of information without error but said that the “automatic, and nearly permanent, retention of every detail” due to synesthesia made it very hard for him to grasp abstract concepts or make sense of what he was reading. Still, synesthesia is generally considered a positive, and most people that have it do not think of it as a “disorder.” 

It’s staggering how the same world you and I experience can actually be so different to so many people. I had no idea that such a condition existed before I was introduced to this tool just a few days ago that allowed me to see what my name looks like to a synesthete. In her video, violinist, composer, and synesthete Kaitlyn Hova recalls finding out in college that not everyone “saw” music as she did. The prevalence of synesthetes within the general population is remarkably high, contrary to what it may seem. As many as 1 in 20 people can have some form of synesthesia, and you probably know a lot of them; you just don’t know that you know them. 

But, now you know that you don’t know that you know them. You get the point. In what follows, Kaitlyn goes on to play an incredible piece on her violin to showcase what she “sees” when she plays it, which really makes me wonder how relatively “colorless” our realities are in comparison. Or are they? You see, we all “visualize” things. We may not see colors for every note on an instrument or have perfect pitch, but we do visualize. It happens all the time: when we’re trying to process large amounts of data, or trying our hand at more artistic ventures, we are trying to see something totally abstract.  One of the more interesting studies regarding synesthesia is the “Bouba-Kiki effect.” 

Take a look at this image: Which one of the shapes looks like it’s called “Bouba” and which one’s called “Kiki”? An overwhelming majority of the initial participants chose the image on the right as Bouba and the one on the left as Kiki, even across languages. Even children as young as 2.5 years have demonstrated this effect. While these findings are not seen in every community, the consensus suggests that the Bouba-Kiki effect is a cue to pre-existing synesthesia-like associations present in all of us. It would reinforce the idea that the neural hyperconnectivity that is responsible for synesthesia is seen in pretty much all babies. But most of us simply lose those connections as we grow older. And that’s the beauty and tragedy of synesthesia, all at once- that we all have it, but that most of us lose it. 

Kaitlyn ends her video by asking what could’ve happened if we were all more conscious of each other’s experiences, and “how different our senses might be from one another.” How we solve a math problem, how we make sense of complex concepts, how we enjoy music - sharing these things could make learning so much more fun. “What does it mean to know you have the correct answer,“ she asks, ”What is that feeling? Is that feeling a color?” 

As a student of the sciences, I find myself wondering, time and time again, how scientists realized some of the most mind-bending, unintuitive truths about the universe. How are they so confident in their findings? Aside from the degrees and credentials, what does it truly mean to know something? What is that feeling of harmony, that creative connection; and why does it soothe our hearts? Whether we can describe these things or not, you and I have felt them - maybe in a painting, or in a ballad, or in a book, but we have all felt them. Answering these questions could help uncover the colors in our mundane but elegant reality, and allow us all to experience a richer consciousness - all whilst using an ability that, deep down, we all possess.

- MA, MM