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Savant Syndrome: not just some stupid rainman

Causes and Explanations for Savant Syndrome and the
Mnemonic Abilities of Savants

Abstract

Savant syndrome is a paradoxical and rare disorder in which a mentally retarded individual possesses a few, narrowly focused fragments of high intelligence, commonly in areas of memory, music, and spatial thought (Yewchuk 1999). The abilities of savants range from unusually gifted when contrasted with their low IQ’s, to phenomenal, with feats like being able to hear a musical composition once and play it back by ear (Young and Nettlebeck 1995), recite quickly every year in which Christmas falls on a Wednesday (Horwitz et. al, 1965), or list the capacities of every hotel in every American city (Jones 1926). However, these subjects typically have a limited comprehension of language, reasoning, or even the meanings of the many things they are able to memorize, although they do seem to enjoy their few activities greatly (Phillips 1930). This disorder occurs in ten percent of autistic individuals and less than one percent of all subjects suffering from brain damage or mental retardation. Overall, half of known savants are autistic and most are male (Rimland 1978). Although no theories to date can satisfactorily explain savant syndrome, much evidence and study suggest that it is genetic and environmental, and arises from individuals’ right brains compensating for left-brain deficiencies (Nurmi et. al., 2003).

Prodigious Savants

Of all known savants, there are only about 100 or so cases recorded throughout history whose abilities are almost inexplicably phenomenal (Treffert 2003). The most common trait of these “prodigious savants” is their seemingly limitless mnemonic skills, with many having eidetic or photographic memories.

Consequently, these few subjects are of particular interest and I will choose to focus on them. One should consider any “scientific” study that attempts to explain for prodigious savants (or all savants) as volatile and not definitive, and the reader should take any generalizations explaining this disorder with a spoonful of salt. By analogy, if just one person were to be killed in a peaceful, small town, then, statistically, this town would have murder rates comparable to large, crime-ridden cities.

Therefore, I feel that the best way to treat the subject of prodigious savants is on a case-by-case basis. Such examples range from the musical talents of ‘Harriet,’ studied by David S. Viscott in 1970, to the knowledgeable ‘K.,’ as recorded by Harold Jones of Columbia University in 1926, to the popular “calendar twins,” who have been researched by so many - each arriving to their own, different conclusions (Howe and Smith, 1988).

Links to Autism

Since savant syndrome occurs most often in autistic patients, perhaps it is best to understand the nature and causes of autism to gain further insight. The three key symptoms of autism are noticeable impairment in social interactions, difficulty with verbal and nonverbal communication, and interested in only very narrow activities (DeLong 1999). A sign of this disorder is uneven brain growth. At birth, autistic infants typically have smaller brain masses than normal infants. As toddlers, they experience a rapid increase in brain growth, which slows down later in childhood but are essentially similar in brain mass to normal people by adulthood (Courchesne et. al., 2003). We should also note that the left hemisphere reaches full development later than the right brain in all people (Treffert 2003). Obviously, this fact, coupled with the uneven brain development in autistic people, should lead to some sort of lateralization in preference to right brain functions.

Much research has also shown that there may be a hereditary and even genetic component, which predisposes individuals to develop savant syndrome. Specifically, as much as 20 genes located on chromosome 15q11-q13 can identify which patients are at risk of becoming autistic (which in turn, may lead to savant syndrome), or developing savant syndrome independent of autism (Nurmi et. al., 2003). Moreover, family members of savants commonly possess similar skills or have a history of mental disorders, suggesting a genetic, or at the very least, an environmental relationship (Young and Nettlebeck 1995).

For example, the first sign of savant syndrome in ‘Harriet’ was when her mother (a music teacher) noticed that “she was lying on her back in her crib and humming in perfect pitch, tempo and phrasing the ‘Caro Nome’ from Rigoletto” after hearing a student perform the piece (Viscott 1970: pg. 498).

Other Factors, Lateralization

Lateralization in favor of right brain functions seems to be the favored explanation for savant syndrome predisposition. The special abilities of savants most commonly occur in activities that are musical or artistic, visually or spatially oriented, or narrowly focused on calendar calculating. In contrast, savants are impaired typically in language comprehension, logic, meaning and symbolism, and abstraction, which are considered mostly as left-brain functions (Howe 1989).

We can see further evidence in patients who develop savant syndrome only after suffering from frontotemporal dementia, particularly localized in the left hemisphere (Miller 2000). These individuals would forget the meaning of words, but develop musical and visual skills where none had existed before. In another case, a child from Mexico suffered a bullet to the left side of his head during a robbery (Brink 1980). Afterwards, he lost many language functions but developed amazing spatial and mechanical abilities - “without instruction he dismantled, reassembled, and modified several multigear bicycles” (pg. 251).

Savants also show lower than normal levels of serotonin in their left hemispheres (DeLong 1999). Furthermore, the reason why savants are mostly male (between four and six to one) could be that testosterone may slow growth in the more vulnerable left hemisphere, resulting in males typically having comparatively larger, compensating right brains (Treffert 2003).

Consequently, savant syndrome may simply arise from of one side of the brain compensating for the other (Howe 1989). Upon testing, this hypothesis becomes increasing credible. One such patient, who “could not be taught to dress himself,” could recite entire stories, but could not comprehend the meanings of them (Phillips 1930: pg. 246). On analogy tests, an autistic savant could answer concrete, associative questions, such as ‘bird is to fly as fish is to ___,’ but failed when asked those that involved reasoning or word meaning - for “potato is to vegetable as veal is to ___,” he would respond, “office” (Howe 1989: pg. 23). When tested on analogies, ‘Harriet’ was unable to see the relation between a nickel and a dime - she would only say, “A nickel is a nickel and a dime is a dime. They are not alike at all.” (Viscott 1970: pg. 504).

The only area in which savants display abstract thinking seems only to be in music. At the age of 14, Leslie Lemke, who suffers from cerebral palsy and blindness, “flawlessly and without hesitation” played Tchaikovsky’s Piano Concerto No. 1 after hearing it once, and with no prior (or thereafter) training. Now, he composes, which certainly requires abstraction to figure correct chord progressions, keys, and so forth (Treffert 2003: pg. 14).

More striking are ‘Harriet’s’ talents: when asked to arrange “Happy Birthday” in the style of famous classical composers, she did so with ease on a piano. Furthermore, she could even arrange the song in the style of one composer with her left while simultaneously playing in a different style with her right (Viscott 1970).

Abilities

As mentioned previously, the abilities of savants generally depend on their mnemonic skills, which beg the questions of how and why they choose to memorize things in such narrowly focused areas of interests, and whether if they understand or appreciate the things they remember. By definition, their strong memories should not be related to their IQ’s, but further study with verbal-association tests confirms this independence (O’Conner and Hermelin 1989).

Their ability to remember does not appear to be simply rote, as once thought, but is “categorically organized” (pg 104). On another test, O'Conner and Hermelin asked these same subjects, who had a good knowledge transport systems, to memorize sets of bus route pairings; scores were generally higher when buses came from the same garage versus randomly paired buses. In a different study, an autistic subject could play back a traditional, normally toned, baroque recording after hearing it once, but found an atonal Bartok to be more difficult (Young and Nettelbeck, 1995).

Several factors may explain why savants are able to memorize so much and so well. As noted earlier, deficiencies in their left-brains actually help them to concentrate better. Without having to think of the meaning or symbolism of things, savants are able to have greater focus simply in literal thinking. It has also been suggested that since savants generally are isolated at homes or institutions, they have fewer distractions (Rimland 1978). Still others have sensory handicaps such a blind girl who developed remarkable calendar calculating - a deprivation in one sense obviously enhances focus on other areas (Rubin 1965).

Furthermore, savant abilities typically are encouraged by family members or doctors, leading to reinforcement and a sense of reward for answering correctly (Howe 1989). For example, the “calendar twins,” only began displaying their skills only after their mother and sisters saw one twin intently focused on an almanac, and encouraged both to learn names of weeks or lengths of months (Horwitz et. al., 1965). Still, others such as ‘Harriet’ acquired her calendar skills out of fear: after she was institutionalized as a child, she began counting days until she could go home (Viscott 1970).

Reservations

I find these theories, however, somewhat inadequate to account for prodigious savants. The most pertinent question, “how?” has not been definitively answered. While musicians and artists spend lifetimes in study and training, the many abilities of prodigious savants seem almost intuitive or innate, as we shall see.

Consider the subject, “K.,” who had an IQ of 74 but knew volumes’ worth of information on every town and city in the United States (Jones 1926). When asked to memorize a string of random numbers, 30249385274, he responded:

30 is the number of days in a month. 249 - if that were 149 it would be the distance from Chicago to Peoria, Illinois. 385 - I once paid $3.85 railroad fare going from Cheyenne, Wyoming to Wheatlands, Wyoming. 274 - I can remember that by putting a 6 in front of it for the time being; 6274 is the seating capacity of the Hippodrome. (pg. 372)

More remarkable (or disturbing) cases lie in calendar calculating. Consider next, the calendar twins: autistic, “severely myopic,” and with IQ’s about 60 at best (Horwitz et. al., 1965: pg. 1077). When one twin was asked the day of the week for October 16 in the year 32011, he answered quickly and correctly. Since they gave so many answers “in a flash,” it was deemed impractical even to measure response rates (Horwitz et. al., 1969: pg. 413). Many doctors became satisfied with the conclusion that the twins were using some sort of algorithm, not accounting for the fact that the pair performed poorly on simple arithmetic tests (Horwitz et. al., 1965).

Another researcher, Oliver W. Sacks (1990), decided that observation would be a better approach. On one such visit, a box of matches fell of a table, scattered its contents, and “they both cried simultaneously” the number, 111 (pg. 199). Then they repeated the number 37 three times. Not only had they “saw the 111” matches, they had factorized the number as well. This startling act corresponded with the mannerisms that Sacks observed when they were ‘calculating’ calendars, that is, they just looked at ceilings or into nothing, as if they were visualizing numbers eidetically.

On another occasion, Sacks saw the twins engaging in a conversation that consisted of exchanging six-digit numbers. “They look, at first, like two connoisseurs wine-tasting, sharing rare tastes, rare appreciations,” he observed (pg. 202). In fact, they were exchanging primes.

The next day, Sacks arrived (equipped with a book of primes) and joined in their ‘conversation’ with an 8-digit number. The twins paused for only a “half-minute... and suddenly, simultaneously, they broke into smiles” (pg. 203). Then one twin dictated a ten-digit prime, to which the other replied with a twelve-digit number. Sacks was unable to keep up because his book only contained so much. By the end of the day, the twins were swapping twenty-digit prime numbers.

Similarities

With a few exceptions such as the blind girl whom Rubin and Monaghan studied (1965), most savants with calendar calculating abilities share common traits. Like the twins, many would stare off into space when asked a question - one would do likewise when answering test questions. One subject, ‘Dave,’ answered “Thursday, that’s black” for one of his questions (Howe and Smith, 1988). As to why, he replied, “they’re black on the kitchen calendar.” ‘Dave’ would often draw calendars he remembered seeing, down to their unique illustrations, leading to the hypothesis that this child was not using algorithms; he just had photographic memory of calendars. Rather unsurprisingly, when asked of his methods, he flatly said, “use me brain” (Howe 1989: pg. 116).

In addition, calendar calculators possess strong mnemonic recollections of many events in every day of their lives. Instead of computing for days of the week for so many decades, they remember them. Perhaps, as I believe, these savants use the days of their lives as anchors, and realizing that calendars are cyclical, are able extend their ranges. Most of them cannot even add or subtract, much less compute algorithms “in a flash.” However, there are limits that appear emotionally related: ‘Harriet’s’ accuracy suffered for dates in the year that her father died (Viscott 1970), and the twins lost their abilities after they were separated in 1977 (Sacks 1990).

Thoughts

The final question is whether if savants appreciate their abilities - I can confidently answer, yes. As we have seen, the twins enjoyed having conversations about prime numbers. ‘K." carried a book with him that he used to write down anything he could (Jones 1926). The Mexican child who suffered a bullet wound loved showing others tricks and inventions he designed (Brink 1980). ‘Harriet,’ who rarely showed emotion and almost never cried (even as an infant), became ";another person" when she was on the piano (Viscott 1970: 507). She even encouraged her researchers to challenge her musical talents, which brought her much amusement. Yet whenever one of her mother’s students sang a note out of tune, she would scream and hit the offender. Evidently, these savants usually lack the skills to articulate and interact. Caught in their own worlds, they have found pleasure in private ways.

Written by Dinah Cheshire
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