Savant syndrome is poorly understood. No widely accepted cognitive theory explains savants' combination of talent and deficit.[4] It has been suggested that individuals with autism are biased towards detail-focused processing and that this cognitive style predisposes both individuals with and without autism to savant talents.[5] Another hypothesis is that savants hyper-systemize, predisposing them to show talent. Hyper-systemizing is an extreme state in the empathizing–systemizing theory that classifies people based on their skills in empathizing with others versus systemizing facts about the external world.[6] Also, the attention to detail shown by many savants is a consequence of enhanced perception or sensory hypersensitivity in these unique individuals.[6][7] It has also been confirmed that some of these savants operate by directly accessing low-level, less-processed information that exists in all human brains but is normally unavailable to conscious awareness.[8]

http://en.wikipedia.org/wiki/Savant_syndrome