Is Daniel Tammet a liar?

[Added November 2011]
In his wondeful book Moonwalking with Einstein
Joshua Foer speaks also about Daniel Tammet. This is the famous
autistic savant that has written a book explaining ,among other
things, how he was able to learn the first 22,514 digits of pi.
Joshua Foer attempts to convince the reader that Daniel Tammet is a liar.
Of course there is no doubt that Tammet has Asperger and that he was able
to memorise all these digits (or to perform other extraordinary feats involving memory). What he criticises is the explanation given by Tammet on how he
managed doing it. The reason is very simple: as he very well explains
in his book, there are methods that can enable anyone to do this and these
methods don’t require extraordinary powers like synaesthesia.
According to someone this is a “misstep” in Foer’s book : see for example
this review.
But my opinion is that in this case, it is better to use the Occam razor until
we have more evidence: why should we believe that this accomplishment was possible by extraordinary powers when normal methods suffice?

How to remember the first 22,000 digits of pi

[Added November 1997]

I have read the book Born in a blue day by # Daniel Tammet. Daniel Tammet has a mild form of autism called Asperger’s syndrome and reports in this extraordinary book how he was able to memorise in a few weeks the first 22,000 digits of pi and then recall them in around 5 hours before a jury that checked the correctness of each digit. As with Luria’s mnemonist the secret seems to be synaesthesia. Daniel sees each digit as a distinct pattern : for example the 9 is blue and tall. To him a string of 10 random digits is like a landscape. In the book he makes some sample drawing of this peculiar landscape that he sees in the mind. What he has done is to build little by little a huge landscape in his mind representing all the 22,000 digits of pi.
In the day of the recall he had only to concentrate himself on the features
of this extraordinary mental painting extracting one by one all the pi digits.

What autistic people can teach us about memory

[Added February 2004]
A small percentage of people with autism have some remarkable abilities: it is the
so called Savant Syndrome.They show mostly artistic abilities (play music or paint).The reason fo these abilities may be a normal right brain hemisphere that compensates for a damaged left hemisphere .
But what about the extraordinary memory that such people show(this phenomenon was depicted in the film Rain man)?The almost limitless memory of savant
people seems to be of the kind called procedural.This is the kind of implicit memory that we use when we learn to do something like riding a bicycle.
This memory is the last to be lost by people with Alzheimer.
Again, it seems that the damage that produces the autism has destroyed the explicit semantic memory, leaving intact this “low-level” memory.
Although the autistic people don’t know the meanings of what they learn,
they are able to remember a lot of things almost without effort. Some autistic savants
become able to describe how they do it. Their account is fascinating and may
be of great help in understanding how the brain works.
For example see the case of Daniel Tammet
and Temple Grandin.