As I wait idly for my friend in a café, I let my thoughts wander. Today is a Monday, so that’s a red day. Accordingly I’m wearing a bright red sweatshirt. I blankly stare at the people around me and colours pop immediately into my mind’s eye. The middle-aged lady with the short black hair chatting animatedly to her friend is a distinct midnight blue. The tall muscular man ordering a cappuccino is a mustard yellow. As my attention wanders to the jazz music playing in the background, the chords I hear are translated into a wonderful shade of pink. Suddenly there is a key change and the colours morph once again, this time into a dark shade of purple. Just as I am lulled into a trance, my friend finally arrives with a female colleague of hers I’ve never met before. I greet her with a smile and reach out to shake her hand. As my hand touches hers, a shot of green lights up in the recesses of my mind.

This is how I experience life. I’m a synesthete.

Synesthesia is a phenomenon where stimulation in one sensory or cognitive modality leads to the subsequent automatic experience in another, often irrelevant, modality. For example, some synesthetes can smell colour, whilst others can taste words. The prevalence of synesthesia in the general population differs somewhat depending on the sources you read, ranging from a sparse 1 in 25,000 (Cytomic, 1989), to 1 in 2000 (Baron-Cohen et al., 1996), to a very common 1 in 100 (Hubbard and Ramachandran, 2005).

The main synesthesia I experience is called grapheme-colour synesthesia where all letters are associated consistently with a distinct colour.  To me, A is red, B is brown, C is yellow, and so forth. Whilst the colour associations with the alphabet are very clear, the colours associated with words take on an added complexity as they depend highly on the first letter. Take my name for example:

‘M’ to me is red, so the initial impression of my name would be as follows:

However, if I let my attention focus on individual letters, their corresponding colours start to pop out:

Hence the resulting colour that emerges from the depths of my awareness ends up becoming a swirling palette of various hues. Grapheme-colour synesthetes can be further classified into ‘associators’ and ‘projectors’ (Dixon, Smilek, & Merikle, 2004). ‘Associators’ – the group I fit in – experience all colour strictly in their mind’s eye. ‘Projectors’ on the other hand, actually physically experience the colour. So this black number 5, would literally look a separate colour, like blue or red, to a projector.

As I presume is the case with most synesthetes, until it is explicitly pointed out that your sensory experiences aren’t, well, ‘normal’, you go on thinking everyone takes in the world in a similar fashion. I remember sitting in a psychology lecture when it suddenly dawned on me that I had synesthesia. Confused, I asked numerous friends whether they really didn’t experience vivid colour associations with letters, words, or months. A world without colour was unthinkable to me. I was met with blank stares.

Blown sideways by this paradigm-shift, I ran back to my room and wrote to my family asking whether they were synethetes. After two, ‘what on earth are you talking about’ replies from my mother and sister, my father wrote back saying he understood exactly what I was talking about. In hindsight this actually should have been no surprise as research has suggested that synesthesia can be hereditary (Baron-Cohen et al., 1996). Interestingly, the type of synesthesia passed on may not necessarily be the same between parent and child (Barnett et al., 2008). This turned out to be the case between my father and I. He has number form synesthesia. Essentially, he sees and feels numbers in 3D space. Here are his exact words detailing his experience:

Series of numbers appear as strings in an unbounded mental space. Strings with semantic content, such as historical years, fall along timelines which change direction at irregular points. A string of ten or a hundred years will appear as a roughly horizontal line floating in mental space, the changes in direction varying from a few degrees to almost ninety.

To give a few examples, the year 1900 marks a ninety-degree inward turn. There are less dramatic turns at 1600, 1800, 1850, and 1940. The turns are always inwards and, for the modern era, to the right. These turns do not cumulate into an angular spiral. Like the motorised cameras that run alongside athletic tracks, my point of view runs along the timeline. When the line changes direction, my point of view follows. At the 1900 point, for example, my mental eye turns ninety-degrees to the right. 

Up to 60 different combinations of synesthesia have been documented up to now (for a fascinating list of these combinations, go here). An unusual mix includes mirror-touch synesthesia, where if an individual with this condition observes somebody touching their arm, they will feel the same sensation on their own arm. Another type of synesthesia I possess, which my friends and colleagues most ask about, is people-colour synesthesia. As I have described in the beginning of this entry, when I look at other people vivid colours light up. When friends find out about this they almost always then ask 1) which colour they are and 2) what that means. I find the second common question quite funny because I have absolutely no idea. I haven’t found any particular link between the colour I see and any personality traits. Sometimes the colours I see with people even surprise me.

Currently there are two different neuroscientific theories proposed to explain why synesthesia occurs. The cross-modality theory suggests that there are increased neural connections between different sensory brain regions in synesthetes (e.g. Rouw & Scholte, 2007). The diminished inhibition theory on the other hand suggests that rather than having more neural connections, synesthetes’ brains simply fail at inhibiting information from other sensory modalities. So when a non-synesthete listens to music for example, the neural excitation in the auditory cortex may ‘leak’ onto other brain regions, but the brain effectively stops this from happening. However, the brains’ of people with synesthesia are believed to have a weak braking mechanism, and as a result the act of listening to music will accidentally activate other seeming irrelevant cortical regions, like the visual cortex (see Eagleman & Goodale, 2009 for further info).

Overall, I would definitely say being a synesthete is a fun thing. I enjoy seeing the various colours pop up in my head. It certainly helps me choose clothes every day – I usually choose colours that correspond to whatever I see as the colour of that day (e.g. Tuesday is yellow).  After all, who doesn’t need more colour in their life?

 

Do you have synesthesia? What kind?  What is your experience with it? Leave any comments below!

 

References

Barnett, K. J., Finucane, C., Asher, J. E., & Bargary…, G. (2008). Familial patterns and the origins of individual differences in synaesthesia. Cognition. Retrieved from http://mobile.www.daysyn.com/Barnettetal2008.pdf

Baron-Cohen, S., Burt, L., Smith-Laittan, F., Harrison, J., & Bolton, P. (1996). Synaesthesia: prevalence and familiality. Perception, 25(9), 1073-1079. Retrieved from http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=8983047

Cytowic, R. E. (1989). Synesthesia and mapping of subjective sensory dimensions. Neurology, 39(6), 849-850. Retrieved from http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=2725882

Day, S. http://www.daysyn.com/types- of- syn.html). Synesthesia: demographic aspects of synesthesia.

Dixon, M. J., Smilek, D., & Merikle, P. M. (2004). Not all synaesthetes are created equal: projector versus associator synaesthetes. Cogn Affect Behav Neurosci, 4(3), 335-343. Retrieved from http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=15535169

Eagleman, D. M., & Goodale, M. A. (2009). Why color synesthesia involves more than color. Trends Cogn Sci, 13(7), 288-292. doi:10.1016/j.tics.2009.03.009

Hubbard, E. M., & Ramachandran, V. S. (2005). Neurocognitive mechanisms of synesthesia. Neuron, 48(3), 509-520. doi:10.1016/j.neuron.2005.10.012

Rouw, R., & Scholte, H. S. (2007). Increased structural connectivity in grapheme-color synesthesia. Nat Neurosci, 10(6), 792-797. doi:10.1038/nn1906