Howard Burton - Investigating Intelligence: A Conversation with John Duncan

What if you could take a pill that would make you more intelligent?

Science fiction? Well, maybe not. Researchers have been studying intelligence for some time now and have begun to make significant progress. But it all starts, of course, with understanding what, exactly, we mean by intelligence in the first place.

In his popular book, How Intelligence Happens, University of Cambridge cognitive scientist John Duncan sets the stage by re-introducing us to the work of the influential English scientist Charles Spearman.

Back in 1904, Spearman discovered that a clear correlation existed between peoples abilities to perform various tasks. Those who were good at one sort of thing tended, in a mathematically quantifiable way, to be good at others. The wider the sample of tasks, the clearer this correlation became. This led Spearman to develop his theory of a so-called g factor or general factor, reflecting a certain aptitude that some people had which enabled them to be successful across a wide range of activities.

Intriguingly, some tasks proved to be fairly reliable indicators of this factor almost all by themselves: Spearman applied his statistical approach to the work of Alfred Binet and others, and the modern IQ test was born.

But what does it all mean?

Well, its hardly straightforward: the road to a more rigorous understanding of human intelligence is fraught with difficulties.

The first is sociological. Many are concerned that such investigations are driven by a dangerous sense of elitist eugenics that seeks to extend itself far beyond any strictly defined sense of cognitive ability.

A common criticism levelled against IQ tests, for example, is that they are motivated by an insidious desire to reduce all human experiences, and all humans, to a single number.

John unhesitatingly dismisses this idea straight away:

Right from the very beginning of the scientific study of cognitive abilities its been perfectly clear that you cannot assess somebodys abilities, and certainly not their worth, through a single number. In fact, there are an infinite number of things that are important to people and we value them for so many different characteristics: their honesty, their good humour, their ability at math, their ability to play football and so onan infinite number of different things. That is the truth; and if you think you can explain everything important about somebody with one test, its obviously doomed. As far as I know, nobody has ever thought that, although many people are criticized for thinking it.

However, what started with the work of the British psychologist Charles Spearman in the early part of the 20th century was the study of something much more specific than that. That was an empirical discovery drawn from experiments on measuring peoples ability to do things; and putting forward a theory to explain it.

The problem is, of course, that the scientific study of intelligence has a nasty habit of running smack into our pre-conceived egalitarian principles.

Its very common to hear that everybody has their strengths, and thats a great thing. But then, meanwhile, you go into the job interview next door and people say, I really like that candidate, thats the smart one. Well, what do they think they mean by that? They dont believe this person will do well at the job because of being good at this or that particular thing, but rather because they just somehow felt that they got more out of them intellectually.

I think people always have an intuitionwhich to some extent, at least, is truethat the same people tend to be able to flexibly address themselves to different sorts of problems. But whats important about a scientific program is that for a given question, such as predicting how well a person will do in a new job when youre interviewing her, this is something that you can actually measure.

But its one thing to measure something and another to truly understand it. If this g factor is a real thing that somehow enables some of us to more flexibly address different sorts of problems, what is it, exactly? And where can it be found in the brain?

Through years of rigorous testing and close examination of brain-imaging technology, Duncan believes hes narrowing in on the answer. The key to g, he believes, lies in a very particular brain network that lies in the frontal and parietal lobes.

Very interestingly, if you gave many different sorts of taskstests of memory or language, or even identifying faces or holding something in short term memorythis same network tends to be a part of the brains response.

So whatever g is, its something thats important in organizing many different sorts of activity, which is just what you should think if its going to explain the g factor. And much of what were doing now is trying to understand whats going on inside these regions of the brain as problems are solved.

The key word here is organizing. John is convinced that the primary role this network plays is to allow us to focus sufficiently on a task at hand in order to select the key thing that enables us to find the solution. That is, in a nutshell, what separates those with high g from those without it, and effectively what we mean when we call someone intelligent.

Focus is really the same thing as selection, if you go into it. It means that you take part of the problem and not the rest. Interestingly, I think this is also very closely related to what many people think of as the heart of whats special about the human mind: the power of abstraction, being able to think abstractly.

Often we tend to think of abstraction in, if you like, rather abstract terms: we think that abstract thinkers are philosophers or those who can tackle complex and recondite problems. I think theres probably a simpler way to think about abstraction as the ability to see the common important thread between a great many instances that are different from one another. This is what we mean by abstraction.

An instance of justice occurs, for example, no matter whether it happened in the court or on the playground. You can see were now very close to the idea of attention or focus: were picking up just one critical aspect of a situation and throwing away all the other things that differ between them.