By David Robson
Are our IQs set to increase forever, or are we on the cusp of decline? David Robson explores the past, present and future of intelligence.
You may not have noticed, but we are living in an intellectual golden age.
Since the intelligence test was invented more than 100 years ago, our IQ scores have been steadily increasing. Even the average person today would have been considered a genius compared to someone born in 1919 – a phenomenon known as the Flynn effect.
We may have to enjoy it while we can. The most recent evidence suggests that this trend may now be slowing. It may even be reversing, meaning that we have already passed the summit of human intellectual potential.
Can we have really reached peak intelligence? And if that is the case, what can the subsequent decline mean for the future of humanity?
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Let’s begin by exploring the ancient origins of human intelligence, from the moment our ancestors began to walk upright more than three million years ago. Scans of fossil skulls suggest that the brains of the first bipedal apes, Australopithecus, were about 400 cubic centimetres – just a third the size of modern humans’.
That comes at a serious cost. The brains of modern humans consume around 20% of the body’s energy, so our bigger brains must have offered some serious benefits to make up for those excess calories.