Do young calendrical calculators improve with age?

The calendrical calculation performance of two 10-year-old children of the same intelligence level (IQ 90) but different calendrical ability, was compared with the performance of eight adult idiot-savant calculators. The calculating speeds of the two 10-year olds fell within the range of the reaction times of the adult savants. No improvement was detectable in a series of successive trials over time, either in speed or accuracy. It is concluded that the young calculators have already inferred rules about calendrical structure and that their performance cannot be accounted for by practice alone, but these savants use cognitive strategies to aid their performance.