Connections Between Language and Intelligence

In a blog from a few weeks ago, I discussed aphasia, the disorder in which there is damage done to certain portions of the brain affecting the ability to use language; the disorder can impair both the expression and understanding of language, as well as reading and writing. But there’s another type of disorder that Steven Pinker discusses in The Language Instinct which seems to do precisely the opposite. Whereas aphasia impairs language, but seems to leave the rest of intelligence more or less intact, individuals suffering from Williams syndrome have good language skills, but bad cognition.

Williams syndrome is a rare genetic condition associated with a defective gene on a chromosome, resulting in this specific form of retardation. Those who suffer from it are generally especially articulate and eloquent and able to speak with fluent grammatical language. In fact, they are much better conversationalists than the average person and incorporate sophisticated vocabulary into their speech.

And yet their IQ is typically between 50 and 70, low enough to qualify them as moderately to mildly retarded. They tend to have limited spatial skills and motor control, and cannot understand mathematical concepts. In fact, virtually no individual with Williams syndrome is living alone; they cannot deal with demands of everyday life. Education psychologist Eleanor Semel comments that in schools, “Educators are confused because the Williams syndrome child tests like the retarded child, talks like a gifted child, behaves like a disturbed child, and functions like a learning-disabled child."

The existence of disorders like aphasia and Williams syndrome—a case in which language is impaired but intelligence is intact and a case in which language is intact but intelligence is impaired—seems to show that intelligence and language are not necessarily interconnected, which may suggest (as Pinker believes to be the case) that the ability to use language is based in our biology, not in our training.

But focusing solely on the Williams syndrome provides further possible insights as to the workings of the brain. Given our discussions in class about the possible connection between language and music , it’s interesting that children with the syndrome generally exhibit “savant-like musical skill”; it seems as though the fact that both their language and music skills remain intact—actually, more than just intact, but heightened—while their intelligence is affected is testimony to the interconnection between the two in the brain.

Using brain scans to compare the brains of affected and unaffected individuals, researchers found that
“cells in the primary visual cortex of carriers of the Williams deletion are smaller and more densely packed -- allowing for fewer connections between cells. Neurons in the primary auditory cortex, on the other hand, were larger and loosely packed, denoting increased connectedness." They believe that it is this greater connectedness of the auditory cortex that leads to increased skill in areas involving auditory phonology in individuals with Williams syndrome.

Apart from better than average skills in discerning music, people with Williams have exuberant personalities and love company and conversation; they talk a lot, and with everyone. They have no difficulty approaching anyone and starting a conversation. Whereas the amygdala (the brain’s main fear processor) shows heightened activity when most of us see angry or worried faces, it shows no reaction when a person with Williams views such faces. As journalist David Dobbs says, “It’s as if they see all faces as friendly.”

Studying the brains of people with Williams shows that while their dorsal areas (the area along the back and top of brain that is thought to be involved with mathematics, vision, and space) are severely underdeveloped, their ventral areas (the area along the front and bottom of the brain that is thought to be involved in language, emotion, and social drive) are unusually rich in synaptic connections. Again, in terms of interconnectivity in the brain, then, it seems as though our social instincts and ability to use language are related—which perhaps reflects the fact that the more effectively we use language, the better we can navigate and communicate in society.

http://www.sciencedaily.com/releases/2006/10/061003191006.htm
http://www.nasw.org/finn/ws.html
http://eands.caltech.edu/articles/LXVI3/genetics.html
The Language Instinct by Steven Pinker