Evolution of human ‘super-brain’ tied to development of bipedalism, tool-making

April 21, 2011

CU-Boulder researcher John Hoffecker, shown here working at a site in Russia dating back 45,000 years, believes there is mounting archaeological evidence for the evolution of a human "super-brain" no later than 75,000 years ago that spurred a modern capacity for novelty and invention (credit: Vance T. Holliday/University of Arizona)

John Hoffecker, an archaeologist at the University of Colorado, Boulder, has attributed the evolving power of the mind to the formation of what he calls the “super-brain” (collective mind), an event that took place in Africa no later than 75,000 years ago.

While the concept of a human super-brain is analogous to social insects like bees and ants, which collectively behave as a super-organism by gathering, processing, and sharing information about their environment, there is one important difference, Hoffecker said. “Human societies are not super-organisms — they are composed of people who are for the most part unrelated, and societies filled with competing individuals and families.”

While crude stone tools crafted by human ancestors beginning about 2.5 million years ago likely were an indirect consequence of bipedalism (walking upright) — which freed up the hands for new functions — the first inklings of a developing super-brain likely began about 1.6 million years ago when early humans began crafting stone hand axes, thought by Hoffecker and others to be one of the first external representations of internal thought.

The emerging modern mind in Africa was marked by a three-fold increase in brain size over 3-million-year-old human ancestors like Lucy, thought by some to be the matriarch of modern humans. Humans were producing perforated shell ornaments, polished bone awls and simple geometric designs incised into lumps of red ochre by 75,000 years ago. “With the appearance of symbols and language — and the consequent integration of brains into a super-brain — the human mind seems to have taken off as a potentially unlimited creative force,” Hoffecker said.

Since the emergence of the modern industrial world beginning roughly 500 years ago, creativity driven by the human super-brain has grown by leaps and bounds, from the invention of mechanical clocks to space shuttles.

Powerful artificial intelligence could blur the differences between humans and computers in the coming centuries, Hoffecker said.

Hoffecker is the author of an upcoming book, “Landscape of the Mind: Human Evolution and the Archaeology of Thought,” to be published by Columbia University Press in May.