6

Interlude

A Final Theory, Knowledge and Intelligence, and a Statement of Belief

Neurological Theory — A View to the Future

All the theories we’ve looked at so far describe what different brains can do. One brain may be good at math or music. Another may take in visual information with unusual speed and accuracy. A third may be especially subtle at understanding the emotions other people are feeling. But where are these different abilities located in brains? That question is the province of neurology — the science that studies nervous systems, including the human brain. Something must be different in the way each of our brains is “wired,” something in each brain’s individual neurology that gives its “owner” his unique characteristics.

A brief caution here: We're always hearing reports that essentially say that we've found the place in the brain where some particular activity takes place. The brain isn't nearly that simple. It is intricately networked, beyond our current ability to more than dimly imagine. Take any one of the ways of being intelligent we've looked at: Interpersonal Intelligence, for example. Surely, working with other people ties together dozens, or hundreds, of brain areas to yield what I blithely summarize as a single capability. Imagine that we find an area which, if damaged, virtually destroys our ability to work with others. That area is apparently a key part of the system that yields our Interpersonal Intelligence. But that's not at all the same thing as saying we've found where Interpersonal Intelligence "is." We just found one of the components.

The promise of Neurological Theory is that we may, one day, be able to show the exact relation between what goes on inside an individual brain and the abilities that brain can demonstrate. It hopes to say how the brain is put together and how the parts function — how it is organized internally and how its electrical and chemical signals eventually yield human behavior. If it succeeds, we’d be much closer to understanding what intelligence really is. (And perhaps even to directly measuring it from brain function.)

With the growth of neuroimaging techniques, this area is rocketing. When I first drafted this section, the cutting-edge research of Michael Posner and Marcus Raichle had just been summarized in their book, Images of Mind. By a clever combination of brain imaging with refinements of an older technique, they found a way to reveal the real-time sequence in which parts of the brain join in a complex task. That research is emblematic of a whole new wave of studies; I imagine the authors might now say that research is mostly of historical interest, so much has happened since. (Even if the research becomes superannuated, the images are amazing, and I think the book will stand as one of the best-designed books of science.)

In my areas of interest, the most exciting recent book to use neuroimaging is Overcoming Dyslexia, by Sally Shaywitz. It is a landmark, because neuroimaging has now let us literally see how the brains of struggling readers differ from those of good readers: different structures, different pathways, and different skill packages. This has given us a practical, research-based understanding of what we can do to help.

This technology is going to revolutionize psychology in all its branches. Eventually, it will allow us to begin to develop a deep understanding of what each part of the brain does. We will begin to understand how the parts of the brain coordinate to do complex human activities. As this line of work progresses, we should be able to see how individual differences in people’s brain activity lead to different levels of performance.

Will we eventually be able to build a theory of intelligence based on detailed knowledge of internal brain functioning? Will we, someday in the far future, have photos and engineering drawings of the Intelligence Elephant? Or will there always be something that eludes us: something greater than the sum of the parts?

Neurology’s potential is huge — but its promise is one for the future. Even now, there are several new intelligence tests that claim to be based in neurological theory. Their value remains to be seen, but, at present, they are certainly based on an incomplete understanding of the neurology of the human brain.

You and I are interested in the knowledge we have now. So let’s travel on! We’ve explored three theories and glanced at a fourth which may be in place to guide our children as they raise the next generation. Each theory we explored — Cognitive Abilities, Multiple Intelligences, and Real-World — will represent a tributary in our eventual map of the Intelligence River. The idea of the Director, which isn’t so much a theory as a collection of important things high-functioning people do, will also add an important tributary to the Intelligence River. Now, before we sketch out that map, I need to touch on several fundamental ideas which will also play a part in our overall map.