Synaesthesia: Hearing music and seeing colours

Many people associate colours with words, sounds and occasionally smells. My associations aren't strong or consistent enough to be considered true synaesthesia, the neurological condition under which normally distinct sensory impressions cross over and blend with one another but there is evidence that experiences, similar to synaesthesia, can be induced in those who don't normally have it. This is accomplished through training or hypnosis, for example.

Recently, there's been a proliferation of art that attempts to capture the essence of synaesthesia in recent years. That's a tough task - how do you communicate such an intrinsically subjective experience? Indeed, few of the works lead to experiences that prove any more stimulating than looking through a kaleidoscope. Would Parfums Pourpres du Soileil des Pôles - a performance piece for three harmonium players and a synaesthete - turn out to be any different?

Many people certainly won't find the individual elements of Parfums prepossessing. During the hour-long performance, the musicians play an uninterrupted succession of glacial arpeggios - sustained chords that are slowly assembled and disassembled, note by note. (Fans of drone will be well satisfied, though.) As they do so, the synaesthete selects and arranges coloured cards to reflect his or her perception of the music, a spectacle reminiscent of watching someone hunting for particular Lego bricks to complete a particularly abstract construction.

While this might not sound very entertaining, there's a certain intellectual fascination to it. During last Wednesday's performance at the South London Gallery, the choreography was by Claude-Samuel Lévine, who arranged the cards in several horizontal rows, continually adding and removing them as the music developed. At times the arrangement became disordered and vaguely resembled a painting by Kandinsky (often believed to be a synaesthete); at others it fell into a strict grid that was more like Mondrian (not a synaesthete).

He later explained that the "y" axis of his arrangement more or less represented musical pitch, and the "x" axis time. What the colours represented proved harder to articulate, at least in terms comprehensible by a non-synaesthete. Lévine clearly felt strongly that his presentation reflected his personal experience. His collaborator Laurent Montaron said that it was much the same each time the piece was performed - a hallmark of true synaesthesia.

Try as they might, however, many people cannot grasp the correspondence between Lévine's actions and the musical progressions. There was one exception, whwn one dramatic key change led to the frenzied construction of a wall of white cards and a second that prompted Lévine to sweep away the multicoloured mass that he had painstakingly assembled for the past 10 minutes.

A couple of my fellow audience-members did claim to have "got it", but it was hard to know how seriously to take those claims. Since synaesthesia has become widely known (perhaps even trendy), it's noticeable that more and more people profess to have it - sometimes offering only the flimsiest of evidence. But trying to compare notes led quickly into the philosophical quagmire of qualia. Inasmuch as the experience of art is necessarily subjective, the experience of synaesthetic art is doubly so; and Montaron says different synaesthetes respond in markedly different ways to the piece, confusing matters still further.

A more common reaction, however, was bafflement, edged with suspicion from some of those encountering synaesthesia for the first time. Synaesthetic art might gratify the eye and ear, but it can also leave you wondering if it's actually possible to communicate effectively across the gulf between the minds of those with and without the condition.

Even the title of the piece - "purple perfumes of the polar sun" in English - is evocative but opaque: it's a line from Metropolitain by the French poet, libertine and synaesthete Arthur Rimbaud. Exactly what Rimbaud was describing in his poem remains the subject of controversy; and it seems a fair bet that the message of Parfums will remain just as elusive - at least to those of us who are not, in the end, special synaesthetic snowflakes.