Are our brains different than those of our ancestors

Mitchell Leslie wrote in Sandford Magazine several years ago:

(W)hat turned humans into a planetary power? Lacking evidence to answer that question, we can only guess at the cause or causes. Among the dozen or so experts focusing on “the leap,” most favor cultural, social or demographic explanations, Klein says. They speculate, for example, that humans suddenly crossed a threshold of creativity after a long, slow buildup in population, or that a radical population boom set off a maelstrom of competition between groups, inspiring rapid innovation.

A few researchers reject the whole notion of a sudden behavioral revolution, arguing instead for slow cultural evolution. Some of the so-called hallmarks of modernity, they say, showed up tens of thousands of years earlier. Noting that the brain reached its full size at least 130,000 years ago, these anthropologists think humans had all the intellect they needed from then on and that modern advances arose one by one over a vast period of time.

Klein suggests a third possibility—a strictly neurological scenario that has gained few followers in a field of study dominated by cultural explanations, he says. Humanity’s big bang, he speculates, was sparked not by an increase in brain size but by a sudden increase in brain quality. Klein thinks a fortuitous genetic mutation may have somehow reorganized the brain around 45,000 years ago, boosting the capacity to innovate. “It’s possible this change produced the modern ability for spoken language,” he says.

Clearly, speech eases communication. But it also fosters something less obvious and equally important. Spoken language, Klein says, “allows people to conceive and model complex natural and social circumstances entirely within their minds.”

Today's Washington Post, in an article ("Learning About Learning: Brain Research May Produce Results in the Classroom" by Nelson Hernandez0 today notes

One of the most startling recent revelations in neuroscience has been that the brain's structure is much more flexible (a concept called neuroplasticity) than was previously thought.

The brain is the organ of thought. The brain may or may not have changed much genetically over the past 130 thousand years, but the way it is used has changed a lot. Neuroplasticity implies not only that brain will assign portions of itself away from seldom used functions to much used functions, but that practice makes it better at the functions that are practiced.

Take athletics as a metaphor. A professional boxer hits much harder than the average person, not only because he has learned how better to throw a punch, but because he has built the muscle power to do so through his training. So too, competitive runners train to run faster, and competitive weight lifters build their muscles and don't look the rest of us.

The first Homo sapiens 130,000 years ago were hunter gatherers. Think how they used their brains. They lived short lives in small communities, and their lives depended on finding food in the wild and avoiding accidents and predators. As children they must have learned mostly by watching their elders. Vocabularies probably would have been simple, heavily biased towards what one would find where.

How different from modern Homo sapiens in the United States, most of whom live in cities, dealing almost exclusively with the artifacts of modern civilizations, having attended schools and learned from books, subjected to a bombardment of information from radio, television, the Internet and media that are even in elevators and on the sides of buses.

Functionally the brains of the first hunter gatherers micht have been as different from modern humans as are the bodies of Michael Phelps and Akebono, the sumo wrestler.