But there has always been something opaque about IQ. In the first place, there’s no consensus about what intelligence is. Some people think intelligence is the ability to adapt to an environment, others that capacity to think abstractly, and so on.
Then there are weird patterns. For example, over the past century, average IQ scores have risen at a rate of about 3 to 6 points per decade. This phenomenon, known as the “Flynn Effect”, has been measured in many countries and across all age groups. Nobody seems to understand why this happens, or why it seems to be petering out in some places, like Scandinavia.
IQ can also be powerfully affected by environment. As Eric Turkheimer of the University of Virginia and others have shown, growing up in poverty can affect your intelligence for the worse. Growing up in an emotionally strangled household also affects IQ.
One of the classic findings of this was made by H M Skeels back in the 30’s. He studied mentally retarded orphans who were put in foster homes. After four years, their IQ's diverged an amazing 50 points from orphans who were not moved.
And the remarkable thing is the mothers who adopted the orphans were themselves mentally retarded and living in a different institution. It wasn’t tutoring that produced the IQ spike; it was love.
Then, finally, there are the various theories of multiple intelligences. We don’t just have one thing called intelligence. We have a lot of distinct mental capacities. These theories thrive, despite resistance from the statisticians, because they explain everyday experience. I’m decent at processing words, but when it comes to calculating the caroms on a pool table, I have the aptitude of a sea slug.
IQ, in other words, is a black box. It measures something, but it’s not clear what it is, or whether it’s good at predicting how people will do in life. Over the past few years, scientists have opened the black box to investigate the brain itself, not a statistical artifact.
Now you can read books about mental capacities in which the subject of IQ and intelligence barely comes up. The authors are concerned instead with, say, the parallel processes that compete for attention in the brain, and how they integrate.
They’re discovering that far from being a cold engine for processing information, neural connections are shaped by emotion.
Today, the research that dominates public conversation is not about raw brain power but about the strengths and consequences of specific processes.
Daniel Schacter of Harvard writes about the vices that flow from the way memory works. Daniel Gilbert, also of Harvard, describes the mistakes people make in perceiving the future. If people at Harvard are moving beyond general intelligence, you know something big is happening.
The cultural consequence is that judging intelligence is less like measuring horsepower in an engine and more like watching ballet. Speed and strength are part of intelligence, and these things can be measured numerically, but the essence of the activity is found in the rhythm and grace and personality – traits that are the products of an idiosyncratic blend of emotions, experiences, motivations and
inheritances.
Recent brain research, rather than reducing everything to electrical impulses and quantifiable pulses, actually enhances our appreciation of human complexity and richness. While psychometrics offered the false allure of objective fact, the new science brings us back into contact with literature, history and the humanities, and, ultimately, to the uniqueness of the individual.
NYT