![]() It suggests that, for an ant at least, having a bigger brain is important for doing well in a large society – but that more complex social systems with greater division of labour might, in contrast, prompt their brains to shrink. When DeSilva's team compared the brain sizes of various ant species, they found that sometimes those with large societies had evolved bigger brains – except when they had also evolved this penchant for fungus-farming. These ants gather leaves and other plant material to use on their farms before harvesting the fungus to eat. Amazingly, there even are ant species that practise a form of agriculture in which they grow huge swathes of fungus inside their nests. A human brain, by comparison, has around 86 billion.īut some ant societies share striking similarities with our own. They are roughly one tenth of a cubic millimetre in volume – or a third the size of a grain of salt – and contain just 250,000 neurons. And so, in a recent paper, they sought inspiration from an unlikely source – the humble ant.Īt first glance, or should I say squint, ant brains might seem hopelessly different to ours. The question as to why this change occurred still hovers. DeSilva and his colleagues note that human bodies have got smaller over time but not enough to account for our reduction in brain volume. What exactly prompts brains to get bigger or smaller over time in a given species also is often difficult to know. So the relationship between brain volume and how humans think can't be a straightforward one. Many species have brains far bigger in size than ours and yet their intelligence – as far as we understand it – is quite different. And it also raises questions about what the size of a brain really reveals about an animal's intelligence, or cognitive ability, in general. It's a question that has left researchers scratching heads. Why, during this age of extraordinary technological development, did human brains start to dwindle in size? The first writing appeared at roughly the same time. Sprawling civilisations, full of architecture and machinery, soon followed. "We were expecting something closer to 30,000 years ago."Īgriculture emerged between 10,000 and 5,000 years ago, although there is some evidence that plant cultivation may have started as early as 23,000 years ago. "This is much more recent than we anticipated," says DeSilva. And according to an analysis of cranial fossils, which he and colleagues published last year, the shrinkage started just 3,000 years ago. The lost volume, on average, would be roughly equivalent to that of four ping pong balls, says Jeremy DeSilva, an anthropologist at Dartmouth College in the US. But since then, human brains have actually shrunk slightly. ![]() The people walking around and meeting in the world's earliest cities would have been familiar in many ways to modern urbanites today. Several thousand years ago, humans reached a milestone in their history – the first known complex civilisations began to emerge. Your ancestors had bigger brains than you. ![]()
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