Primate Evolution

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We can now trace the evolution of our brains from its earliest beginnings to its recent decline. David Robson reports A brief history of the brain We can now trace the evolution of the brain from its earliest beginnings to its recent decline. David Robson tells its story IT IS 30,000 years ago. A man enters a narrow cave in what is now the south of France. By the flickering light of a tallow lamp, he eases his way through to the furthest chamber. On one of the stone overhangs, he sketches in charcoal a picture of the head of a bison looming above a woman's naked body. In 1933, Pablo Picasso creates a strikingly similar image, called Minotaur Assaulting Girl. That two artists, separated by 30 millennia, should produce such similar work…show more content…
Mastering the social niceties of group living requires a lot of brain power. Robin Dunbar at the University of Oxford thinks this might explain the enormous expansion of the frontal regions of the primate neocortex, particularly in the apes. "You need more computing power to handle those relationships," he says. Dunbar has shown there is a strong relationship between the size of primate groups, the frequency of their interactions with one another and the size of the frontal neocortex in various species. Besides increasing in size, these frontal regions also became better connected, both within themselves, and to other parts of the brain that deal with sensory input and motor control. Such changes can even be seen in the individual neurons within these regions, which have evolved more input and output points. All of which equipped the later primates with an extraordinary ability to integrate and process the information reaching their bodies, and then control their actions based on this kind of deliberative reasoning. Besides increasing their overall intelligence, this eventually leads to some kind of abstract thought: the more the brain processes incoming information, the more it starts to identify and search for overarching patterns that are a step away from the concrete, physical objects in front of the…show more content…
But to support a 10-fold increase in the "clock speed" of our neurons, our brain would need to burn energy at the same rate as Usain Bolt's legs during a 100-metre sprint. The 10,000-calorie-a-day diet of Olympic swimmer Michael Phelps would pale in comparison. Not only did the growth in the size of our brains cease around 200,000 years ago, in the past 10,000 to 15,000 years the average size of the human brain compared with our body has shrunk by 3 or 4 per cent. Some see this as no cause for concern. Size, after all, isn't everything, and it's perfectly possible that the brain has simply evolved to make better use of less grey and white matter. That would seem to fit with some genetic studies, which suggest that our brain's wiring is more efficient now than it was in the past. Others, however, think this shrinkage is a sign of a slight decline in our general mental abilities. David Geary at the University of Missouri-Columbia, for one, believes that once complex societies developed, the less intelligent could survive on the backs of their smarter peers, whereas in the past, they would have died -- or at least failed to find a
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