All of the evidence gathered by talented anthropologists over the years has proven Charles Darwin's famous theory that our brains have an extensive evolutionary history that developed over millions of years.

Neuroscientists have embellished this evidence by proclaiming an old prehistoric brain is still lurking beneath our newly acquired higher brain functions. They claim many of the higher centers most recently acquired in our brains, communicate with others via the prehistoric lower ones.

What has happened over human evolutionary history is clear--that certain parts of the human brain have become enlarged or reduced relative to others. This primarily occurred through a long process known to scientists as random mutation where the brain used a form of trial and error to meet the challenges imposed on it by forces in the environment and within its own drive to improve reproduction.

Beyond Prehistoric Brain Size

The size of the brain is not the only factor in prehistoric brain development. The inner organization of the brain is of great importance as well. If we had this information, we could better understand the behaviors of each hominid species. Anthropologists have been successful in determining prehistoric brain sizes, but it is difficult to know how the brain was structured or folded within the cranium -- no fossils exist of the inner tissue of these brains.

The Brain's Evolutionary Process

There is a biological mechanism recently discovered which may explain how members of a species may adapt their brains to undergo rapid evolutionary change.

A study, published in The Journal of Neuroscience, 1992 was conducted by Robert Williams, M.D., Professor at the University of Tennessee College of Medicine, on a 20,000 year old species of wildcat, the direct ascendant species to that of the domestic cat.

A fluke of nature allowed the living fossil, Felis silvestris tartessia to have survived unchanged for the past 20,000 years. Thus, comparing the two cats would show the evolutionary changes between them over a 20,000 year span.

The biological process uncovered in the study showed both species of cats had the same amount of brain cells as fetuses, but there was a selective process that killed off different sets of neurons before birth. This process resulted in each cat's brain being better adapted to fit into its environment.

This was the first study ever conducted linking brain cell death with evolution. Most surprising in its results was the speed of the evolutionary process of the domestic cat. Dr. Leo Chalupa, professor of neuroscience at the University of California at Davis, said "Very few people in neuroscience take an evolutionary perspective and this is a very important finding." Other scientists caution that, though it is an innovative idea, there is not enough data to confirm cell death is linked to the evolutionary process.   

Can We Clone a Neandertal's DNA?

Perhaps the only way we would ever know our ancient ancestor's behaviors for certain, is by obtaining a DNA specimen and then cloning it -- but this is a highly unlikely scenario to occur. Though some of our ancestors existed during the ice age, such as the Neandertals, we have only obtained a few human specimens preserved in ice. Recently, two DNA specimens were extracted from the bones of Neandertals, but cloning such a species remains a far fetched idea. Ultimately, the only way we may ever be able to determine actual behaviors of our prehistoric ancestors, is by studying the prehistoric parts of our own brains.

Information Derived From:

Becoming Human, Ian Tattersall,
Harvest Publishing, 1998

Evolution of Tabby Cat Mapped in Brain Study,
The Science Times Book of the Brain, 1998

The Mind's Past, Michael S. Gazzaniga
University of California Press, 1998