Different tasks involve different shapes, and I also have various sensations or emotions for certain numbers. Whenever I multiply with 11 I always experience a feeling of the digits tumbling downwards in my head. I find 6s hardest to remember of all the numbers, because I experience them as tiny black dots, without any distinctive shape or texture. I would describe them as like little gaps or holes. I have visual and sometimes emotional responses to every number up to 10,000, like having my own visual, numerical vocabulary.
And just like a poet's choice of words, I find some combinations of numbers more beautiful than others: ones go well with darker numbers like 8s and 9s, but not so well with 6s. A telephone number with the sequence 189 is much more beautiful to me than one with a sequence like 116.
This aesthetic dimension to my synesthesia is something that has its ups and downs. If I see a number I experience as particularly beautiful on a shop sign or a car license plate, there's a shiver of excitement and pleasure. On the other hand, if the numbers don't match my experience of them -- if, for example, a shop sign's price has "99 pence" in red or green (instead of blue) -- then I find that uncomfortable and irritating.
It is not known how many savants have synesthetic experiences to help them in the areas they excel in. One reason for this is that, like Raymond Babbitt, many suffer profound disability, preventing them from explaining to others how they do the things that they do. I am fortunate not to suffer from any of the most severe impairments that often come with abilities such as mine.
Like most individuals with savant syndrome, I am also on the autistic spectrum. I have Asperger's syndrome, a relatively mild and high-functioning form of autism that affects around 1 in every 300 people in the United Kingdom. According to a 2001 study by the U.K.'s National Autistic Society, nearly half of all adults with Asperger's syndrome are not diagnosed until after the age of sixteen. I was finally diagnosed at age twenty-five following tests and an interview at the Autism Research Centre in Cambridge.
Autism, including Asperger's syndrome, is defined by the presence of impairments affecting social interaction, communication, and imagination (problems with abstract or flexible thought and empathy, for example). Diagnosis is not easy and cannot be made by a blood test or brain scan; doctors have to observe behavior and study the individual's developmental history from infancy.
People with Asperger's often have good language skills and are able to lead relatively normal lives. Many have above-average IQs and excel in areas that involve logical or visual thinking. Like other forms of autism, Asperger's is a condition affecting many more men than women (around 80 percent of autistics and 90 percent of those diagnosed with Asperger's are men). Single-mindedness is a defining characteristic, as is a strong drive to analyze detail and identify rules and patterns in systems. Specialized skills involving memory, numbers, and mathematics are common. It is not known for certain what causes someone to have Asperger's, though it is something you are born with.