Can you imagine having your whole life mapped out like a board game where you are the game character? Some individuals perceive their environment in a way that is different from the rest of us. This phenomenon is a seldomly known condition called synesthesia.
Synesthesia is a condition where stimulation of one sense results in a concurrent perception in the same or another modality (1)Hanggi, J., Wotruba, D., & Jancke, L. (2011). Globally Altered Structural Brain Network Topology in Grapheme-Color Synesthesia. Journal of Neuroscience, 31(15), 5816–5828. doi: 10.1523/jneurosci.0964-10.2011. Unlike other psychological conditions it cannot be found in the DSM-V or the ICD-11, since this special form of perception is not classified as a psychopathology (2)Reinberger, S. (2017, September 18). Synästhesie: Farbwahrnehmung und Hirnforschung. Retrieved from https://www.dasgehirn.info/wahrnehmen/truegerische-wahrnehmung/milde-musik-und-zickige-zahlen?gclid=EAIaIQobChMIurDWlPTP3wIVxOR3Ch2hTQHqEAAYASAAEgKY6_D_BwE. By many synesthetes, it is rather considered a gift of experiencing a concurrent perception – like colour – while perceiving a stimulus – like a tone – from their surroundings. By breaking down this experience, we can differ between an inducing stimulus (inducer) and a concurrent perception (concurrent) (3)Hänggi, J., Beeli, G., Oechslin, M. S., & Jäncke, L. (2008). The multiple synaesthete E.S. — Neuroanatomical basis of interval-taste and tone-colour synaesthesia. NeuroImage, 43(2), 192–203. doi: 10.1016/j.neuroimage.2008.07.018. Many different forms of synesthesia have been documented.
Black and white weekends
Gloria, one of my former colleagues, has synesthesia. For her, each weekday has a different colour. She starts the week with a red Monday, followed by a blue Tuesday and, after the remaining yellow, orange and brown weekdays, her week ends with a black and white weekend. But more than that Gloria also perceives her life similar to a game board. She describes this experience as having a very specific vision of her own life, where the board has different colours depending on seasons or events. Within her life’s board, she can change perspectives. For example, she has the possibility to look at a whole year or zoom a specific day, which then itself has a spatial structure of different ups and downs.
Gloria’s spatial representation of her life as a game board can be classified as visual-spatial synesthesia. Another example of synesthesia is a Swiss musician who experiences colors when she hears a tone, called tone-color-synesthesia. She also tastes different flavors when she hears tone intervals (sound-taste-synesthesia) (4)Sulser, E. (n.d.). Synesthesia. Retrieved from http://www.elisabethsulser.ch/en/synaesthesie/. . Her rare gustatory experiences make a major second taste bitter and a minor third, salty. As you can see, there are a variety of ways in which this condition can manifest, not only among synesthetes but also within synesthetes. Around half of those gifted with one type of that perceptual phenomenon, also experience a second or more types of synesthesia (5)Cytowic, R. E. (2018). Synesthesia . Cambridge, Massachusetts: Massachusetts Institute of Technology ..
Characteristics of synesthesia
Learning the formal definitions of synesthesia can lead to questioning your perceptions, such as maybe considering the letter “A” as female gendered or thinking a Sunday can be connected with yellow since the sun is also associated with yellow. This leads to asking the question, “Am I a synesthete?” The answer is no.
One of the main characteristics for synesthesia is the automaticity the concurrent comes with (6)Ward, J. (2013). Synesthesia. Annual Review of Psychology, 64(1), 49–75. doi: 10.1146/annurev-psych-113011-143840. This means a synesthete does not choose to see the color red, or does not think about the gender of a certain letter. Instead these perceptions are just “there” and have always been.
Another substantial aspect is the consistency of this connection (7)Ward, J. (2013). Synesthesia. Annual Review of Psychology, 64(1), 49–75. doi: 10.1146/annurev-psych-113011-143840. In cases of synesthesia, consistency means that the established connections between the inducer and the concurrent are always the same. For instance, when hearing the pitch of C you do not see red one time and green the next time, instead hearing the pitch of C always triggers the color red.
Prevalence and the synesthetic brain
Even though the prevalence of synesthesia is estimated to be around 4.4% of the population (8)Synesthesia research (2016, March 10). FAQ : Synaesthesia research. Retrieved from http://www.sussex.ac.uk/synaesthesia/faq#acquired, a lot of synesthetes do not know about their condition, since they do not perceive it as something special. When my former colleague Gloria figured out that she was a synesthete in eleventh grade, and she told her parents about it, her father described similar experiences. This situation is certainly not unique, considering that around 40% of synesthetes know at least one family member who also has synesthesia (9)Synesthesia research (2016, March 10). FAQ : Synaesthesia research. Retrieved from http://www.sussex.ac.uk/synaesthesia/faq#acquired. A high familial clustering like that hints towards a genetic component that influences the manifestation of synesthesia.
Several articles imply underlying mechanisms that determine the occurrence of synesthesia. Previous research has not yet identified a definite cause for this perceptual phenomenon. Some researchers suggest a hyperconnectivity between involved brain areas (10)Hanggi, J., Wotruba, D., & Jancke, L. (2011). Globally Altered Structural Brain Network Topology in Grapheme-Color Synesthesia. Journal of Neuroscience, 31(15), 5816–5828. doi: 10.1523/jneurosci.0964-10.2011. Other research talks about the possibility of disinhibition of feedback; a theory which proposes that reduced inhibition leads to a hyperexcitability, and thus to communication between brain areas that would normally work separately from each other (11)Reinberger, S. (2017, September 18). Synästhesie: Farbwahrnehmung und Hirnforschung. Retrieved from https://www.dasgehirn.info/wahrnehmen/truegerische-wahrnehmung/milde-musik-und-zickige-zahlen?gclid=EAIaIQobChMIurDWlPTP3wIVxOR3Ch2hTQHqEAAYASAAEgKY6_D_BwE. Independently of what theory has the most support, or if they intermingle with each other, evidence found in brain imaging studies imply a different organisation of white matter in synesthetes compared to “non-synesthetes” (12)Synesthesia research (2016, March 10). FAQ : Synaesthesia research. Retrieved from http://www.sussex.ac.uk/synaesthesia/faq#acquired.
On a personal note
While working on this article, a friend of mine discovered that she has synesthesia. Her brain attributes a gender, and sometimes even personality traits, to the letters of the alphabet. She describes for example:
“the letter G is definitely female for me. All my life, I have always perceived the letter G as an older woman. She is really strict and even mean sometimes, (…) like a strict teacher. From her character and appearance, I would compare her to Miss Finster from Disney’s Recess TV show. She is not married and lives alone”.
There is no easy way to describe synesthesia due to its’ various manifestations in different individuals, but this is also part of its attractiveness. So if after reading this, you realize that your perception is also a little different from others, you might find yourself in the world of synesthesia.
Referanseliste