Tuesday, July 14, 2009

Why Are Human Brains So Big?

Human brains are about three times as large as those of our early australopithecines ancestors that lived 4 million to 2 million years ago, and for years, scientists have wondered how our brains got so big. A new study suggests social competition could be behind the increase in brain size. Credit: NIH, NIDA

From Live Science:

There are many ways to try to explain why human brains today are so big compared to those of early humans, but the major cause may be social competition, new research suggests.

But with several competing ideas, the issue remains a matter of debate.

Compared to almost all other animals, human brains are larger as a percentage of body weight. And since the emergence of the first species in our Homo genus (Homo habilis) about 2 million years ago, the human brain has doubled in size. And when compared to earlier ancestors, such as australopithecines that lived 4 million to 2 million years ago, our brains are three times as large. For years, scientists have wondered what could account for this increase.

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