James Lee, a professor of psychology at the University of Minnesota whose research examines the genetic basis of intelligence, provided some background to explain why vocabulary might be one of our best indicators of a person’s general intelligence and not just an indication of a person’s socioeconomic class, upbringing, and, education. These elements clearly play a role in determining what and how many words a person knows, as demonstrated in the influential work of Betty Hart and Todd Risley, who showed that educational inequalities among nine-year-olds from different socioeconomic correlated closely with the sheer number of words they heard in their first three years of life. For Hart and Risley, words are beaks.
In classical IQ science, words are feathers because, without denying the importance of exposure to words, there is more to vocabulary acquisition and knowledge than exposure. In older, behaviorist models of word acquisition, children were believed to learn words simply through association. A kid hears the word “ball” in the presence of said object enough times, and he links the sound to the concept.
Nowadays, Lee explained, thanks to the work of Paul Bloom and others, many psychologists think that word learning “is actually a quite rational process, and not , to concepts through repetition; they “parse what they hear into segments and use all the intellectual skills at their disposal to figure out what these individual words mean.” It is a small cognitive marvel every time a child or an adult for that matter learns a new word, which is why a large vocabulary can be a sign of an innate intellectual ability. Lee warned that much more study remains to be done on this subject. It seems likely that, given an equal playing field, differences in innate intelligence probably account for some differences in the sizes of individuals’ lexicons, so, yes, vocabulary can serve a plumage function. The problem is that we are a long way from a society in which all children grow up in rich linguistic environments, and the insidious effects that appear to be a product of this particular kind of poverty suggest that words are also beaks that allow us to think more efficiently and with greater complexity about our world.
There are two fundamental ways difficult words make us smarter: They bundle concepts together so that they can be recalled and mentally manipulated. And they help us cut fine distinctions in our thinking about the world. Some difficult words chunk and other chisel. Unfortunately, the same qualities that allow these words to contribute to our intelligence also make them more difficult to master and, thus, less frequently used in speech and writing, which only makes them harder to learn.
Borrowing the concept of chunking from cognitive psychology, Hirsch argued in “A Wealth of Words,”
Words are fantastically effective chunking devices. Suppose you put a single item into your working memory—say, “Pasteur.” So long as you hold in your long-term memory a lot of associations with that name, you don’t need to dredge them up and try to cram them into your working memory. The name serves as a brief proxy for whatever aspects will turn out to be needed to cope with your problem.
Of course, this chunking only works once you have mastered all the concepts that the word bundles together. “Topology” would not strike most mathematicians as difficult, but that is only because they are immersed in their particular domain of knowledge.