Savant syndrome (/sæˈvɑːnt,səˈvɑːnt,ˈsævənt/) is a phenomenon where someone demonstrates exceptional aptitude in one domain, such as art or mathematics, despite significant social or intellectual impairment.[1]
Savant syndrome is estimated to affect around one in a million people.[4] The condition affects more males than females, at a ratio of 6:1.[1] The first medical account of the condition was in 1783.[1] Approximately half of savants are autistic; the other half often have some form of central nervous system injury or disease.[1] It is estimated that between 0.5% up to 10% of those with autism have some form of savant abilities.[1][6][7] It is estimated that there are fewer than a hundred prodigious savants, with skills so extraordinary that they would be considered spectacular even for a non-impaired person, currently living.[1]
Savant skills are usually found in one or more of five major areas: art, memory, arithmetic, musical abilities, and spatial skills.[1] The most common kinds of savants are calendrical savants,[8][9] "human calendars" who can calculate the day of the week for any given date with speed and accuracy, or recall personal memories from any given date. Advanced memory is the key "superpower" in savant abilities.[8]
Calendrical savants
A calendrical savant (or calendar savant) is someone who – despite having an intellectual disability – can name the day of the week of a date, or vice versa, on a limited range of decades or certain millennia.[9][10] The rarity of human calendar calculators is possibly due to the lack of motivation to develop such skills among the general population, although mathematicians have developed formulas that allow them to obtain similar skills.[10] Calendrical savants, on the other hand, may not be prone to invest in socially engaging skills.[11]
Mechanism
Psychological
No widely accepted cognitive theory explains savants' combination of talent and deficit.[12] It has been suggested that individuals with autism are biased towards detail-focused processing and that this cognitive style predisposes individuals either with or without autism to savant talents.[13] Another hypothesis is that savants hyper-systemize, thereby giving an impression of 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.[14] Also, the attention to detail of savants is a consequence of enhanced perception or sensory hypersensitivity in these unique individuals.[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.[16]
Neurological
In some cases, savant syndrome can be induced following severe head trauma to the left anterior temporal lobe.[1] Savant syndrome has been artificially replicated using low-frequency transcranial magnetic stimulation to temporarily disable this area of the brain.[17]
There are no objectively definitive statistics about how many people have savant skills. The estimates range from "exceedingly rare"[18] to one in ten people with autism having savant skills in varying degrees.[1] A 2009 British study of 137 parents of autistic children found that 28% believe their children met the criteria for a savant skill, defined as a skill or power "at a level that would be unusual even for 'normal' people".[19] As many as 50 cases of sudden or acquired savant syndrome have been reported.[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.[23]
History
The term idiot savant (French for "learned idiot") was first used to describe the condition in 1887 by John Langdon Down, who is known for his description of Down syndrome. The term idiot savant was later described as a misnomer because not all reported cases fit the definition of idiot, originally used for a person with a very severe intellectual disability. The term autistic savant [fr] was also used as a description of the disorder. Like idiot savant, the term came to be considered a misnomer because only half of those who were diagnosed with savant syndrome were autistic. Upon realization of the need for accuracy of diagnosis and dignity towards the individual, the term savant syndrome became widely accepted terminology.[1][18]
