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This chart shows the world getting smarter

Zack Beauchamp is a senior correspondent at Vox, where he covers ideology and challenges to democracy, both at home and abroad. Before coming to Vox in 2014, he edited TP Ideas, a section of Think Progress devoted to the ideas shaping our political world.

Raven's Progressive Matrices are a type of intelligence test, one well-respected by psychologists. And according to a new study reported by the BBC, researchers have found something fascinating — scores on the test have been going up for decades, especially in the developing world. It really looks like people are getting smarter:

bbc intelligence test

We've known for a long time that people have been scoring higher and higher on IQ tests. There's even a name for the phenomenon: the Flynn effect, named after the professor — James Flynn — who first documented it.

What's interesting about this new study, from King's College London researchers Peera Wongupparaj, Veena Kumari, and Robin Morris, is both its sophisticated methodology (it did complex analysis on data from over 200,000 people) and the sharp convergence between the developed and developing world.

As the Center for Global Development's Charles Kenny points out, the finding suggests that intelligence is not something that's entirely innate or genetic. Rather, differences in intelligence scores between groups of people appear to largely reflect differences in social circumstances.

But what social circumstances, exactly? That's the million dollar question, and it turns out no one's quite sure. We know, for example, that poverty can artificially depress IQ scores. So it'd make sense that, as the BBC's William Kremer reports, the largest gains in intelligence scores were in India and China, which have also seen major declines in poverty in the last half century.

That explanation doesn't necessarily fit as well in the developed world, where IQ levels in some countries — such as France and Scandinavia — have flatlined even as the countries have gotten richer, according to Flynn. Researchers have proposed a number of possible contributing factors, ranging from better education to better nutrition to the spread of electric lighting (really). It's a fascinating, important subject — and one on which this new study definitely isn't the last word.

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