Bloodthirsty brains – new research challenges view of human intelligence

2016-09-01 09:14

Cape Town – Researchers in South Africa and Australia have published findings that challenge commonly held views on the evolutionary development of the human brain.

Their work unseats previous theories that the progression of human intelligence is simply related to the increase in the size of the brain.

Hominin skull casts
Hominin skull casts. (Photo credit: Roger Seymour. Sourced from the South Australian Museum, Adelaide, Australia.) 

They found that while brain size increased about 350% over human evolution, blood flow to the brain increased by 600%.

It appeared the human brain had evolved to become not only larger, but more energetically costly and bloodthirsty than previously believed.

The research is a collaboration between Wits University research entities (The Brain Function Research Group and Evolutionary Studies Institute) and the cardiovascular physiology team at the University of Adelaide.

Co-author Dr Edward Snelling, from Wits, said ancient fossil skulls from Africa revealed holes where the arteries supplying the brain passed through.

Increasingly energetic connections

"The size of these holes show how blood flow increased from 3 million-year-old Australopithecus to modern humans," he said.

"The intensity of brain activity was, before now, believed to have been taken to the grave with our ancestors."

Professor Emeritus Roger Seymour, from Adelaide, used the size of these holes to calculate the change in blood flow over time.

"To allow our brain to be so intelligent, it must be constantly fed oxygen and nutrients from the blood. The more metabolically active the brain is, the more blood it requires, so the supply arteries are larger," said Seymour.

He said the holes in fossil skulls were accurate gauges of arterial size.

"We believe this is possibly related to the brain's need to satisfy increasingly energetic connections between nerve cells that allowed the evolution of complex thinking and learning."

The findings of their study have been published in the Royal Society Open Science journal.

- Read the study here.

Read more on:    wits university  |  evolution  |  paleontology

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