What is Synesthesia?

So far, I've mostly been talking about how we perceive color and the applications of it. Today, I'll diverge from these topics and begin exploring what happens when the internal workings of our visual senses deviates from the norm. With that, I'll specifically be looking at synesthesia!

Retrieved from knowingneurons

So, what exactly is synesthesia? 

The word synesthesia comes from two Greek words: "syn" (together) and "aisthesis" (perception) — literally meaning "joined perception" (Phillips). In other words, synesthesia is a neurological condition in which one sense (e.g hearing) is simultaneously perceived by one or more additional senses (e.g sight) (Phillips). An individual with this condition are referred to as a synesthete. Synesthesia can involve any of the senses in several different combinations.

Using my handy-dandy search in Wikipedia, I found that there are several forms of synesthesia — a few of which I will list below:

Grapheme-color synesthesia, Retrieved from Mysid

The most common form is grapheme-color synesthesia, in which people see certain a color in response to a certain letter of the alphabet or number. For example, the letter A may be associated with red; the number 5 may associated with green, and so forth. 

Another common form of synesthesia is chromesthesia, which associates sound with color. For some, everyday sounds (e.g: doors opening, cars honking, people talking, etc.) can trigger seeing colors. For others, colors are only triggered when musical notes/keys are played. 

There are also other forms, such as spatial sequence synesthesia (numerical sequences are seen as points in space), number form (mental map of numbers that automatically and involuntarily appears whenever the individual thinks of numbers), ordinal linguistic personification (ordered sequences such as ordinal numbers, week-day names, months, etc. are associated with personalities or genders), lexical-gustatory synesthesia (certain tastes are experienced when hearing words), and so forth.

Interestingly, individuals with synesthesia may not have the same sensual associations between one another. For instance, the sound of a music note may represent as blue to some, while others may perceive it to be orange. Moreover, synesthetes can have a combination of these different forms; they're not limited to just one type of synesthesia. Overall, people with synesthesia comprise of about 1% of the population (Phillips). 

What causes synesthesia?

The development of synesthesia is still currently unknown, though several hypotheses have been formed around this condition.

It's suggested that synesthesia develops during childhood when children are intensively engaged with abstract concepts for the first time, thus leading to correlations (in other words, this is a learned condition). This semantic vacuum hypothesis explains why the most common forms of synesthesia are grapheme-color, spatial sequence and number form. However, with this hypothesis, it would mean that those with synesthesia could simply unlearn this condition, which is not the case at all. In fact, synesthesia is a life-long condition, so I share my skepticism on this hypothesis. Interestingly, for non-synesthetes, some forms of synthesthia can apparently be learned by creating forced associations (Baxter). 

Some scientists believe that synesthesia occurs because of "crossed-wiring" in the brain  (Phillips). It's hypothesized that in synesthetes, neurons and synapses that are meant to be contained within one sensory system cross to another sensory system. The reasoning as to why this happens is still unclear, but some researchers believe that everyone has these crossed connections at birth (Phillips). It is only later in life that these connections refined, thus many children possess crossed connections but later lose them. Hence, in a way, adult synesthetes may have simply retained these crossed connections. Of course, these are hypotheses, so skepticism is warranted (e.g: at what age, then, can children differentiate these connections? why is it that only some retain these connections? So many questions!).

Ultimately, more research is needed if we ever want any answers to the why's and how's of this condition.

How do people live with synesthesia?

I personally don't have synesthesia of any sort; however, it was super interesting to learn from the personal accounts of individuals that do have this condition. Many say that synesthesia is more helpful than a hindrance. 

In fact, some genius mathematicians with grapheme-color synesthesia utilize color to help them logic through seemingly impossible problems at lightning speeds (Baxter). Another subset of synesthete mathematicians can see numbers as shapes, making larger numbers easier to digest. People with music-related synesthesia may also have perfect pitch because seeing/hearing colors can aid them in identifying notes or keys (Northwell Health).

Another instance of usefulness is in memorizing long words. This particular synesthete mentions how she can memorize long words after only seeing it once because of the powerful color combinations she sees! She can tell if something is wrong with a spelling because there isn't enough of a specific color in the scheme. Moreover, patterns in writings (such as alliteration) can jump out to synesthete in vivid fashion. In this Ted-Talk video, the speaker goes into detail about how synesthesia has influenced her paintings. 

Phantom colors, retrieved from Edhubbard 

Of course, synesthesia isn't always seen as an extra helping hand. For some synesthetes, a page of math or words can be overwhelming. In this different Ted-Talk video, the speaker goes into how she grew up with synesthesia, the findings of synesthesia, and how she was able to adapt to her surroundings despite her condition. One of the most interesting things I learned from this video was how some synesthetes actually perceive words. Rather than just having a letter blocked in complete colors, some synesthete can see "phantom colors" instead (as seen in the figure).

On an interesting side-note, while researching about synesthesia, I learned that Vladimir Nabokov, author of Lolita (a book I'm currently reading for one of my classes), has grapheme-color synesthesia. This leaves me in awe, as any other reader of his works will also understand how eloquent his prose is.

"Perhaps 'hearing' is not quite accurate, since the color sensation seems to be produced by the very act of my orally forming a given letter while I imagine its outline. The long a of the English alphabet ... has for me the tint of weathered wood, but a French a evokes polished ebony... The word for rainbow, a primary, but decidedly muddy, rainbow, is in my private language the hardly pronounceable: kzspygv." - Vladimir Nabokov

Honestly, reading people's accounts on synesthesia made me a bit saddened by the fact that I can never truly experience nor grasp even a glimpse of what these people go through on a daily basis.  Despite its own fair share of troubles, the uniqueness in their ability to perceive things is a difference that that they definitely shouldn't be ashamed about. Hopefully reading this gives you as much awe and curiosity as it did for me!

The exploration of this condition is a good leeway to next week's topic. As promised from way back, next week, I'll be looking into forms of color blindness! Again, feel free to share any visual-perception conditions of interest for me to research.