Synaesthesia: The strangest thing by John Harrison, Oxford University
Press, 拢16.99, ISBN 0192632450
IT鈥橲 always a treat to stumble onto a book that promises to enlighten you
about yourself. In Synaesthesia I found just that. Here鈥檚 a book that
investigates not just any old brain, but brains like mine, brains that have a
weird and unexplained propensity to mix up senses.
For ten years now, John Harrison, formerly a neuropsychologist at the
University of Cambridge, has been pondering what synaesthesia is all about. He鈥檚
long been persuaded that the people telling him they hear words in colour or
smell smells in shapes are not having him on. A 鈥渢est of genuineness鈥� he devised
with colleagues confirms that a synaesthete who is asked which colour they
associate with particular letters, words or numbers will give the same answer
now as they did years ago.
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I admire his respect for subjective reports, but it鈥檚 the book鈥檚 scepticism I
enjoy most. Harrison examines historical figures who either claimed to have had
synaesthesia or who had that honour bestowed on them by other people. He looks
at, among others, poets Arthur Rimbaud and Charles Baudelaire, composers
Aleksandr Scriabin and Nikolai Rimsky-Korsakov, and painters Wassily Kandinsky
and David Hockney鈥攁ll of whose creative works seem in one way or another
to draw on synaesthetic associations. He stops short of saying they did not or
don鈥檛 have the condition鈥攈e can鈥檛 know for sure鈥攂ut he says there is
not enough evidence. It could, he points out, be mere metaphor. Or even wishful
thinking.
Synaesthesia, he says, isn鈥檛 something that you suddenly acquire. It goes
back as far as a person can remember. Although one synaesthete seldom agrees
with another鈥攅ven a relative鈥攁bout the colour of a word or sound, a
synaesthete鈥檚 own take on it never changes. Apart from the apparent merging of
the senses, there is nothing unusual about synaesthetes, apart from the fact
that women outnumber men by about 9 to 1.
Harrison isn鈥檛 easily convinced by theories purporting to explain the
condition. His own theory is that neural connections we all have as infants, and
which in most people are pared down, stay intact in synaesthetes. Even this
doesn鈥檛 seem to persuade him fully.
If there is a problem with the book, it is its balance. There is too much in
the way of background explanation. Do we really need to be given crash courses
in Mendelian inheritance, statistical significance and even the difference
between psychoanalysts, psychologists and psychiatrists?
Elsewhere, though, I want so much more鈥攅specially more analysis. I
would have liked more space given to the competing theories of what might cause
the condition, and why they might be flawed. Intriguing theories shouldn鈥檛 be
summed up and dismissed in less than a page. How about more discussion on Peter
Grossenbacher鈥檚 idea that synaesthesia is caused by excessive 鈥渇eed-backward鈥�
communication from brain areas now known to integrate multiple senses? And why
not a better exploration of the suggestion that synaesthesia is no more than
childhood associations 鈥渉ard-wired鈥� into the brain? Harrison does not mention
other ideas at all: for example, that neighbouring brain areas responsible for
colour, form and space may simply invade each other.
It鈥檚 not that he is deliberately skimping on his competitors鈥� theories to
puff up his own. I want more of his theory and experimentation too. When he
studies a synaesthete who is perfectly consistent over time in her descriptions
of smell-induced shapes, he found absolutely nothing unusual in her brain scan.
He doesn鈥檛 even speculate about what this means.
And when he discusses how synaesthesia may be genetic, he suggests that the
overwhelming preponderance of females must mean that the trait kills off males
in the womb. Really? This harmless little condition could be fatal to my unborn
male offspring? How? And what does it mean for the males who survive and have
the condition?
If anyone could have sifted through it with a supremely critical eye,
Harrison鈥檚 the man. Sadly, he didn鈥檛. A hundred more pages, please.