Savant syndrome (/ˈsævənt, sæˈvɑːnt/ SAV-ənt, sə-VAHNT, US also /səˈvɑːnt/ sav-AHNT) is a phenomenon where someone demonstrates exceptional aptitude in one domain, such as art or mathematics, despite significant social or intellectual impairment.

[1][6][7] It is estimated that fewer than one hundred prodigious savants are currently living, with skills so extraordinary that they would be considered spectacular even among unimpaired individuals.

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.

[14][15] It has also been hypothesized that some savants operate by directly accessing deep, unfiltered information that exists in all human brains that is not normally available to conscious awareness.

[1] Savant syndrome has been artificially replicated using low-frequency transcranial magnetic stimulation to temporarily disable this area of the brain.

[20][21] Males diagnosed with savant syndrome outnumber females by roughly 6:1 (in Finland),[22] slightly higher than the sex ratio disparity for autism spectrum disorders of 4.3:1.

Down noted that they were all male, none had a family history of similar talents, and that the extraordinary memory was usually associated with "very great defect of reasoning power".