The typical Williams facility with language, however, does not extend to most spatial abilities. Asked to draw a bicycle, a person with Down syndrome will come up with something that's crude but recognizable. Someone with Williams syndrome, on the other hand, will produce a drawing with the person underneath the bike, the chain stretched out below the wheels, and the pedals off to the lower left, connected to nothing. All the parts are there, but they're not in the correct relationship to each other. Bellugi has shown as much with a test in which she briefly presents a card with a large letter D made up of many small Y s and asks children to reproduce what they saw.
Normal children reproduce the figure accurately.
Children with Down syndrome generally draw a large D , ignoring the little Y s. Children with Williams syndrome, however, will draw a collection of Y s, but it won't be arranged in the shape of a D . One group seems to see just the forest, while the other sees only the trees. Because language is generally handled by the brain's left hemisphere and spatial abilities by the right hemisphere, one might be tempted to conclude that Williams syndrome is purely a right hemisphere disorder. But other peaks and valleys of ability make it clear that this is not the case. For example, Williams adults are at least as good as normal adults at recognizing faces, which is typically a function of the right hemisphere.