Intelligence is notoriously difficult to define, but we’re getting there!

It’s a little like love: We all know about it, but where is it? What is it? Among the seemingly endless questions, we’re starting to make some headway in understanding intelligence.

Psychology research has proposed two general categories of intelligence. In 1971, psychologist Raymond Cattell coined the terms fluid and crystallized intelligence, differentiating between the two ways we think.

Fluid intelligence is our ability to think logically, and solve novel problems. This type of thinking underpins the act of reasoning. It allows us to see patterns, and solve things that we haven’t been taught explicitly.

Crystallized intelligence, on the other hand, is the storehouse of information or how-to knowledge that we accumulate throughout our lives. Crystallized intelligence helps us with many things, from answering those general knowledge questions at pub quizzes, to ensuring we remember how to ride a bicycle.

While our crystallized intelligence is constantly growing, scientists agreed that fluid intelligence was unchangeable. Up until now.

It was understood that fluid intelligence reached its peak in early adulthood, around the time you might go to university. A peak at that age explains why most of the influential work done by mathematicians, musicians and physicists occurs in their twenties, and rapidly slows after that.

Moreover, fluid intelligence is closely linked to how our brains are physically structured. So, just as we’d never be able to go to the gym to train our eyes to change from brown to blue, we can’t memorize numbers and then solve equations we’ve never seen before! Or can we?

New evidence suggests we can. To find out, we need to overcome one sizeable hurdle: how can we measure fluid intelligence in the first place? The next blink covers the methods that work.