Source: NYTimes, Apr 2012
Psychologists have long regarded intelligence as coming in two flavors: crystallized intelligence, the treasure trove of stored-up information and how-to knowledge (the sort of thing tested on “Jeopardy!” or put to use when you ride a bicycle); and fluid intelligence. Crystallized intelligence grows as you age; fluid intelligence has long been known to peak in early adulthood, around college age, and then to decline gradually. And unlike physical conditioning, which can transform 98-pound weaklings into hunks, fluid intelligence has always been considered impervious to training.
That, after all, is the premise of I.Q. tests, or at least the portion that measures fluid intelligence: we can test you now and predict all sorts of things in the future, because fluid intelligence supposedly sets in early and is fairly immutable. While parents, teachers and others play an essential role in establishing an environment in which a child’s intellect can grow, even Tiger Mothers generally expect only higher grades will come from their children’s diligence — not better brains.
How, then, could watching black cats in a haunted house possibly increase something as profound as fluid intelligence? Because the deceptively simple game, it turns out, targets the most elemental of cognitive skills: “working” memory. What long-term memory is to crystallized intelligence, working memory is to fluid intelligence. Working memory is more than just the ability to remember a telephone number long enough to dial it; it’s the capacity to manipulate the information you’re holding in your head — to add or subtract those numbers, place them in reverse order or sort them from high to low. Understanding a metaphor or an analogy is equally dependent on working memory; you can’t follow even a simple statement like “See Jane run” if you can’t put together how “see” and “Jane” connect with “run.” Without it, you can’t make sense of anything.
The training tasks generally require only 15 to 25 minutes of work per day, five days a week, and have been found to improve scores on tests of fluid intelligence in as little as four weeks.
Improvement in working memory, in other words, transferred to improvement on a task the children weren’t training for.
… while most skills improve with practice, the improvement is generally domain-specific: you don’t get better at Sudoku by doing crosswords. And fluid intelligence was not just another skill; it was the ultimate cognitive ability underlying all mental skills, and supposedly immune from the usual benefits of practice. To find that training on a working-memory task could result in an increase in fluid intelligence would be cognitive psychology’s equivalent of discovering particles traveling faster than light.
While studies of twins suggest that intelligence has a fixed genetic component, at least 20 to 50 percent of the variation in I.Q. is due to other factors, whether social, school or family-based. Even more telling, average I.Q.’s have been rising steadily for a century as access to schooling and technology expands, a phenomenon known as the Flynn Effect.
At the University of California, Berkeley, Silvia Bunge, director of a laboratory on the building blocks of cognition, takes what she calls “an everything-but-the-kitchen-sink approach.” Working with 28 children from low socioeconomic backgrounds, she assigned half of them to play games designed to boost the speed of response times, and the other half to play games that target reasoning skills. “Quirkle,” for instance, challenges children to align tiles on a grid to match shapes and colors. After eight weeks of training — 75 minutes per day, twice a week — Bunge found that the children in the reasoning group scored, on average, 10 points higher on a nonverbal I.Q. test than they had before the training. Four of the 17 children who played the reasoning games gained an average of more than 20 points.