Think about this: every time you hear the doorbell ring, you get a taste of potato chips in your mouth! Not so bad? What about getting the odour of rotten eggs each time you see a spherical object?

These are only partly jokes. All people suffering from synaesthesia get these kinds of 'dual sensation'. Actually synaesthesia is the production of a sense impression relating to one sense or part of the body by stimulation of another sense or part of the body. In simpler terms, synaesthesia is the condition whereby one sensory experience generates another.

A less exaggerated example of what a synesthete may 'sense' would be the appearance of a black letter "R" on a white background, as always being a blue letter "R"! This is the slightly transformed world of the grapheme-colour synesthete.

To confirm that grapheme-colour synesthetes really see the reported colours, scientists performed some behavioural tests.

A person not suffering from synaesthesia, when asked to comment on this graphic, will probably start with the fact that there are a lot of letters. Then after some time, the person will spot a ring of letters in the middle of the graphic. But will he be able to know what letter of the alphabet is forming this ring? Can you determine the letter?

This is more or less what a person suffering from severe grapheme-colour synaesthesia will see when observing that same black and white graphic. Note that contrarily to what this graphic shows, the synesthete will see each letter having a more or less unique colour. For clarity of this graphic however, each row of letters has been given a single colour. The synesthete clearly sees that there is a ring of letters in the middle of the graphic. And he easily spots that the letter is "R."

As the results of these tests arrived however, it was spotted that not all synesthetes performed equally well. Eduard Hubbard, author of a paper on grapheme-colour synesthetes, says more work has to be done to know the specific types of synesthetic experience. Two most probable types though are the 'higher' synesthetes, whose colours are driven by the concept of the letter and 'lower' synesthetes, whose colours are driven rather by the appearance of the letter.

But why exactly are all these researches important? Hubbard says;

'By gaining an understanding of how the synesthetic brain functions, we may gain an understanding of important aspects of human perception, cognition and development.'

To me personally though, to understand the why of synaesthesia means to get a step closer to the synesthete. All the research will help bring people together. Synaesthesia provides a unique window to the mind but also forms part of the flyover which will help bridge the gap between us, 'normal' people and them, 'unique' people. Hence, another way in which science helps to make the world a better place to live in.

Maybe I'll just shut up now.

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