Researchers Continue to Learn From Williams Syndrome
> 7/9/2007 2:26:20 PM

Ask a person with Williams Syndrome what the symptoms are, and you might hear about elfin facial features, poor spatial reasoning, and heart problems. What you will undoubtedly hear is a staggering quantity of words, because the most noted symptom of the syndrome is an overflowing desire to engage in conversation. The same genetic deletion that prevents them from completing simple jigsaw puzzles or holding a steady job leaves them able to chatter with surprising fluency--it is this mysterious cognitive imbalance that has made Williams Syndrome such a hot subject for researchers and the subject of a New York Times magazine article this week.

Despite the fact that Williams Syndrome is 50 time less prevalent than autism, its unique mix of traits has drawn intense attention. Neurogeneticist Julie Korenberg told the New York Times, “It is the most compelling model available for studying the genetic bases of human behavior.” The model is particularly useful for explaining linguistic and social behavior because of the juxtaposition of high and low abilities, but real insight only begins when differences in brain function are precisely determined. The Times relays a number of broad generalizations and presents a case study of one child, Nicki Hornbaker, but it does not always delve into the details where the true explanatory power lies.

The neurolinguist Ursula Bellugi went deep into the details when she compared Williams children with a Down Syndrome group that had equivalent general IQ scores. The Times reports on his observation that Williams children were far more verbose and gregarious, but tests determined much finer distinctions.

It is not enough to say that those with Williams Syndrome talk more than those with similar IQs. We must ask why and how they speak so readily. As for why, perhaps they are compelled by an overwhelming instinct to use language or perhaps they get an inordinate amount of pleasure from communicating. The first of these hypotheses is probably incorrect, because Williams infants actually take longer than average to begin speaking. They do, however, have a powerful drive to make eye contact before they are able to speak. Dr. Allan Reiss, director of the Center for Interdisciplinary Brain Scienses Research, suggests that this intense gaze means that, unlike autistic children, Williams children crave connection with other humans. Because their language ability is relatively intact compared to their other skills, they focus on this easy source of pleasure and further develop the ability through practice.

Given the very low IQs of those with Williams, it might be suggested that the syndrome merely induces a parrot-like blather with no true understanding. However, Bellugi’s extensive tests showed that they have a deep understanding of language. Not only can they answer questions about complicated grammatical structures like “The horse is chased by the man,” but they can even talk about language itself and point out the mistakes in incorrectly constructed sentences. This is important for the field of neurolinguistics, because it demonstrates that language does not require advanced general intelligence. This gives some credence to the position of linguists like Noam Chomsky who insist that humans must have a specialized language organ because even very intelligent beings could not learn all the rules of language from scratch as quickly as humans do.

Though those with Williams achieve a level of language skill equivalent to the general population, there are some abnormalities that hint that they may process things differently. For example, they use uncommon words with much greater frequency. The reason for this is not clear, but perhaps it is connected to an elevated auditory sensitivity observed in many people with Williams. When Bellugi presented them with sentences that ended in jarringly incorrect ways, those with Williams showed greater arousal. They also show a response to these abnormal sentences that begins about a 100 milliseconds before the normal population, suggesting that they may process some language in an accelerated way. Possibly connected to this phenomenon is the fact that those with Williams are many times more likely to have perfect pitch, the ability to precisely identify sounds without help from any external reference.

Those with Williams also display an abnormal amount of emotional affect, regardless of how many times they are telling the same story or who they are telling it to. They clearly have a strong theory of mind, and add frequent statements about what characters are thinking and feeling (complete with impressions of emotion-laden tone) when asked to create a narration for a picture-book. Yet, they seem unable to pick up some negative social cues. It is difficult to extricate oneself from a conversation with someone with Williams, because they have trouble detecting impatience, disinterest, or even anger. This selective social inability is yet another mystery of the syndrome. The Times suggests that a study led by Karen Berman for the N.I.M.H. may hold the key to this puzzle. Berman found that there was a malfunctioning connection between the amygdala (the fear center) and the orbitofrontal cortex (social context analyzer). When people with Williams are shown threatening faces, they have no response. Yet, they have a normal response to pictures of threatening animals and objects. Those with Williams may be unable to pick up social cues, or alternatively, they may have never been motivated to pick up negative cues because they do not fear them. We, who cringe at the thought of a disapproving or cunning face, study other people careful for signs of what we instinctually want to avoid. Someone not ruled by this fear has no compunction about speaking to strangers and little motivation to pick out subtleties and lies.

Those with Williams have smaller brains, but retain relatively large neocortexes. It was suggested that this language center has grown to compensate for general stroke-like impairments in the right hemisphere, where spatial thinking is centered. However, Bellugi’s research suggests that this is not the case because specific spatial abilities are preserved. Those with Williams are adept at recognizing faces even though they have trouble discriminating inanimate objects. They show a similar ability for the task of determining the age and sex of faces, which was previously shown to be unrelated to the narrow task of facial recognition difficult for some stroke victims. Those with Williams are also good at recognizing some objects when presented in unorthodox manners, like a telephone seen from a viewpoint under the arch of the handset. It is possible that those with Williams have divergent performance on spatial tasks not because they have brain lesions, but because they use different processing strategies.

Along this vein, we can examine the way that those with Williams fail in a different way than those with Down Syndrome when asked to reproduce pictures. These pictures were large objects made up by a multitude of smaller images, like a giant letter T comprised of hundreds of X’s. Those with Down Syndrome reproduced the larger shape without capturing the smaller parts, and those with Williams Syndrome drew the small parts while losing track of the larger picture.

Those with Williams are like the proverbial wise-men describing an elephant from touch. When asked to draw an elephant, they drew many detailed parts with no real coherence and bearing little resemblance to a complete animal. Yet, as wise-men often do, they were able to defend their flawed creations with eloquence after the fact: “It has long grey ears, fan ears, ears that can blow in the wind”. In some ways, we too are groping in the dark to understand this complex array of symptoms. Hopefully, we will soon be able to combine all the details into a complete picture. Even if Williams Syndrome is never fully understood, the study of its impairments and abundancies will yield valuable insight into the way that the human mind handles linguistic, spatial, and social tasks. And with a better understanding, we might be able to better integrate those with Williams into society and help train them for happy and productive lives.

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