Synesthesia

Synesthesia varies from synesthete to synesthete. Even synesthetes with the same form of synesthesia will react differently: for one the letter A may be red but for another it may be light green, or Beethoven's 5th symphony may smell produce sharp, burnt orange lines for one and purple and pink swirls for another. However, after many years of research on synesthesia, the cause and mechanism behind it remains unknown, but the majority of researchers do agree on a basic set of diagnostic criteria (Dann, 1998):

 

1. Synesthesia cannot be produced at will. It is an involuntary response to stimuli and cannot be suppressed (Dann, 1998). This is why synesthesia seems like a terrible burden to those who do not have it; non-synesthetes see it as being potentially annoying and distracting. However those with synesthesia often pity non-synesthetes, saying that there is not an "extra" sensation in their lives but that people without synesthesia are missing something from theirs (Ward, 2008). 

 

2. Synesthesia is not often perceived in the "mind's eye" but rather projected externally or internally with a specific location (Dann, 1998). Synesthetic percepts are perceived differently depending on the synesthete. This concept of where percepts are perceived is typically only seen in color-type synesthetes. For few synesthetes, their percepts are more like feelings, where, in reaction to a stimulus, they get a strong sense of color. More commonly however is the projection of the percept externally or internally with the percept having a specific location. For some, the percept occupies real, physical space in the visual field, similar to a hallucination, and for others the percept is a transparent "overlay" on objects. 

 

3. Synesthetic perceptions remain the same throughout the individual's lifetime, and the perceptions are specific and simple (Dann, 1998). No matter the type of synesthesia a person has, the same stimuli will always produce the same synesthetic percepts. These percepts are developed early in life and remain the same into adulthood. Many studies have tested synesthetes in childhood about the color of their alphabetic letters, only to retest them 5 - 10 years later only to find out the colors had remained, for the most part, constant (Cytowic & Eagleman, 2009). For the percepts themselves, they are typically very specific color- and shape-wise. For sound to sight synesthetes, the shapes they see in response to sound are typically simple, geometric shapes, not detailed picturesque images (Cytowic & Eagleman, 2009). (More about synesthesia types here)

 

4. Synesthetic perceptions are memorable (Dann, 1998). Synesthetic percepts are easily and vividly remembered by synesthetes, often better than the original stimulus. Some synesthetes claim that their colors or number forms help them remember, however like stated before, sometimes the precept is the thing remembered instead of a phone number or address. But this doesn't mean they don't remember the phone number, instead they remember "red-blue-green-yellow-yellow-red-pink", for which each color stands for a number (Cytowic & Eagleman, 2009). (More about synesthesia types here)

 

5. Synesthesia is emotional (Dann, 1998). For most synesthetes, synesthetic percepts are connected to emotions. The strongest percepts tend to be related to the first information children learn. For example, for a color-grapheme synesthete, certain alphabet letters will have stronger colors because those were the first letters that were learned (Dann, 1998). Loss of color or other synesthetic percepts has also been correlated with death or serious illness. Synesthetes suffering from a loss of a loved one or some other tragic event have reported a loss of their synesthesia, usually returning after grieving has subsided (Cytowic & Eagleman, 2009). (More about synesthesia types here)

 

6. Synesthesia is non-verbal (Dann, 1998). Synesthesia is extremely difficult for synesthetes to describe to nonsynesthetes. Some synesthetes with artistic ability attempt to re-create their synesthetic percepts with different mediums, but the creations are always imperfect, leading the synesthete to become frustrated at the inability to communicate effectively (Ward, 2008). (More about synesthesia types here)

 

7. Synesthesia is not a brain dysfunction (Dann, 1998). Synesthesia occurs in people with normal, non-injured brains, which is why it puzzles researcher's so much. It occurs in women more than men, and with all of its forms combined, synesthesia is very rare (almost one in twenty-five thousand). It is not classified as a dysfunction, but more of a mental ability, considering most synesthetes are average to above-average mentally and are often creative (Dann, 1998). (More about synesthesia and the brain found here)