Autistic savants and negative capability

This Guardian interview with "autistic savant" Daniel Tammet suggests a possible connection between autism and synaesthesia.

Tammet is calculating 377 multiplied by 795. Actually, he isn't "calculating": there is nothing conscious about what he is doing. He arrives at the answer instantly. Since his epileptic fit, he has been able to see numbers as shapes, colours and textures. The number two, for instance, is a motion, and five is a clap of thunder. "When I multiply numbers together, I see two shapes. The image starts to change and evolve, and a third shape emerges. That's the answer. It's mental imagery. It's like maths without having to think."

Scientists are particularly interested in Tammet because, unlike most people with autism, he is able to describe his thought process. This description is wonderfully evocative of a state of negative capability:

One day his brother asked him a sum. "He asked me to multiply something in my head - like 'What is 82 x 82 x 82 x 82?' I just looked at the floor and closed my eyes. My back went very straight and I made my hands into fists. But after five or 10 seconds, the answer just flowed out of my mouth. He asked me several others, and I got every one right."

Professor Allan Snyder, also interviewed by the Guardian, believes that we all possess such extraordinary abilities and it is just a question of us learning how to access them:

"Savants have usually had some kind of brain damage. Whether it's an onset of dementia later in life, a blow to the head or, in the case of Daniel, an epileptic fit. And it's that brain damage which creates the savant. I think that it's possible for a perfectly normal person to have access to these abilities..."