The brain of modern humans is more globular, while the brain of the earliest Homo sapiens was elongated. Photo by MPI EVA/ S. Neubauer, Ph. Gunz
Jan. 25 (UPI) -- New analysis suggests the development of the modern human brain was a late chapter in the evolutionary history of the Homo sapien.
Scientists at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, first analyzed the skull shapes of the earliest Homo sapien specimens in 2017. Their researcher revealed an elongated braincase resembling the skull of the Neanderthals. Modern humans, on the other hand, feature a rounder braincase.
In a followup study, published this week in the journal Science Advances, scientists used advanced imaging technology, including micro computed tomography, to more accurately render the inner structure of the braincase, what's known as the endocast. The endocast offers scientists a better idea of what the brain itself was like.
Researchers measured the endocasts of a variety of Homo sapien specimens, from ancient to modern. The measurements reveal a gradual transition from an elongated endocranial shape to a more globular brain.
Only fossils younger than 35,000 years feature a globular braincase shape similar to those found among of modern humans.
The transformation was associated with two cerebral processes, parietal and cerebellar bulging. Parietal systems are essential orientation, attention, perception, motor control, self-awareness, memory and more. The cerebellum assists with motor-related functions, in addition to powering spatial processing, decision making, language and social cognition.
These unique parts of the brain evolved independently of brain size, researchers confirmed.
"The brain is arguably the most important organ for the abilities that make us human," paleoanthropologist Simon Neubauer said in a news release. "But modern human brain shape was not established at the origin of our species together with other key features of craniodental morphology."
Scientists were surprised to find the modern brain made such a significant transformation so recently in human history.
Scientists suggest the changes were triggered by shifts in the early development of the human brain. In modern humans, the young brain takes on its recognizable globular shape within a few months of birth.
"The gradual evolution of modern human brain shape seems to parallel the gradual emergence of behavioral modernity as seen from the archeological record," said researcher Jean-Jacques Hublin.