Summary: This term is from the French, meaning 'wise idiot'.
(Nowadays of course, to be 'politically correct' one is supposed
to use the term 'savant syndrome'). In this variety of subnormal
individual, although generally functioning intellectually at a
low level the person has abilities in a limited field which are
appreciably beyond this. Of course, intellectual abilities are
correlated and we would not expect to find such cases very often,
they are statistically improbable. Typical cases show special
abilities in music, or art. Less interestingly we see cases where
the individual is able to perform tricks like giving the day, if
provided with a date, a month and a year, and the reverse. Two
cases of this less interesting type were studied in the mid-80's
at a residential school for boys. Both individuals were, I think,
operating generally at around the borderline intellectual
level. It was fairly easy to question them and work out that they
were actually quickly calculating the answer using a very logical
system.
Cases A and B.
Questioning revealed that case A was using this method:-
He would know, by rote memory?, e.g. that the 16th April 1986 fell on a Wednesday. Obviously from this it is easy to work out that the 19th April 1986 will be a Saturday. But it also follows therefore that the 16th April of the previous year, 1985 must fall on a Tuesday, and the 16th April of the succeeding year, 1987, on a Thursday. By some means he had fixed some dates of one (or more?) years in his memory, and from this worked out all others. He even made allowances for leap years!
Conversations with the other boy revealed that his method of linking a date with a day involved recalling special days, days when something very nice, (or bad), happened to him, e.g. birthdays.
How and why did they learn this system? Presumably it reflects
one of those slightly bizarre and obsessional interests that is
supposedly another trademark of the 'autistic' individual.
They must have spent a great deal of time studying calendars!