If we were really smart, we’d get over our fixation on the IQ test | David Olusoga

Scores are falling across the world, provoking headlines of 'dumbing down'. But what does it measure anyway?

IQ tests have a troubled history. Although their inventor, the intellectually cautious Frenchman Alfred Binet, understood and acknowledged their limitations, many of those who went on to deploy and develop his ideas did not. Within years of their emergence, IQ tests were being used by US eugenicists to weed out the "feebleminded", and by politicians keen to cloak their calls for greater racial segregation and changes to American immigration laws with a degree of scientific legitimacy.

From the start, Binet's tests were also drawn into the debate over whether human intelligence is predominantly hereditary or better understood as a reflection of environmental factors such as education - one part of the sprawling nature v nurture debate.