It has been called “the most fundamental change in human behavior” that ever occurred. About 50,000 years ago, human beings began to produce art and develop innovative new technologies that allowed them to master their environment as never before. Population increased and Homo sapiens spread rapidly around the globe displacing cousins such as Neanderthals. A significant evolutionary advance in human neurological capacity must have occurred. Yet the appearance of culturally modern humans is an event without an apparent cause.
Where did modern humans originate? The answer may be hidden underneath a cow pasture in Oklahoma. Abandoned for more than eighty years, what could be one of the most important archeological sites on earth lies neglected and forgotten.
In the 1920s A. H. Holloman operated a commercial gravel pit near the small town of Frederick, Oklahoma. Holloman began to find both animal fossils and human artifacts interspersed among the gravels. A friend of Holloman’s wrote to the editor of Scientific American concerning the finds. Subsequent visits by paleontologist Harold Cook and museum director J. D. Figgins resulted in publications describing both fossils and human artifacts from the Holloman Pit.
Almost immediately, the Holloman site became the subject of controversy. Fossils associated with the artifacts appeared to be from the Pleistoceneepoch, about 150,000 years before present. Found among the Pleistocene fauna were arrowheads that anthropologist Leslie Spier described as “resembling modern Indian forms.” Even in the 1920s, this was regarded as impossible. The archeological consensus was that humans had evolved in the Old World and only entered the Americas during the Holocene epoch starting about 10,000 years ago.
Every possible objection was raised as to why the artifacts from Holloman could not be of Pleistocene age. Without bothering to visit the Holloman site, Leslie Spier argued that the arrowheads must have fallen into the pit from the surface. Another critic speculated that the gravel deposits represented a recent reworking and mixing of Pleistocene fossils with Holocene artifacts.
All objections were met and defeated. In 1929 Mr. Holloman located an arrowhead cemented in place. A team of geologists from the University of Oklahoma led by Charles Gould visited the Holloman site and satisfied themselves as to the in situ nature of the artifact. Even critic Leslie Spier conceded that the human artifacts were of the same age as the fossil animals.
Yet the controversy continued. Tired of the contentious quarrelling, in 1932 Mr. Holloman closed the site. A 1955 retrospective published by the Oklahoma Geological Survey concluded “it is a scientific tragedy that the disagreement among observers and scientists caused all to cease collecting and observing the pit.” Despite its apparent promise, the Holloman site was never systematically excavated.
By 1965 North American archeologists had acceded to moving the date of first human occupation in America back to the late Pleistocene. Dating of a site near Clovis, New Mexico suggested that humans first entered the Western Hemisphere about 11,500 bp when an ice-free corridor opened up that would have allowed entry into the continental interior. The Clovis-first theory seemed to have extraordinary explanatory power and it remained the ruling theory for more than thirty years.
For US archeologists, Clovis-first became dogmatic truth. No one looked for an older human presence in the Americas because everyone knew that the Clovis culture was first. When archeological excavations reached the Clovis level, digging stopped. But Central and South American archeologists were unencumbered by preconceived notions. Not knowing that pre-Clovis occupation was impossible they went out and discovered it. Excavations in Brazil and Mexico uncovered evidence of a human presence in the Americas as early as 295,000 bp.
In 1997 US archeologists were finally forced to abandon their beloved Clovis-first theory. Excavations at Monte Verde, Chile, by Tom Dillehay and his colleagues definitively documented a human presence in South America during pre-Clovis times. Yet the accepted date of first entry into the Americas was barely nudged back from 11,500 bp to 15,000 bp.
Archeologists have yet to come to terms with the reams of evidence documenting a human presence in the Americas as early as 300,000 bp. It is likely that humans evolved initially in Africa. But they didn’t remain there very long. Homo is a highly mobile species. Hominids were in the Republic of Georgia by 1,800,000 bp and people occupied cold climates in northern Europe as early as 780,000 bp.
The Bering Land Bridge between Asia and Alaska was open for about 200,000 of the last 500,000 years. Yet we are supposed to believe that Homo sapiens only entered the Americas 15,000 years ago, even though Homo erectus was in east Asia as early as 1,500,000 bp. It is more likely that hominids moved back and forth over the Bering Land Bridge repeatedly.
The currently fashionable theory is that the modern humans evolved in Africa about 50,000 bp and then migrated throughout the world, displacing other forms of Homo such as Neanderthals. Yet there are numerous difficulties with this theory and little evidence in support.
The most significant problem with the Out-of-Africa theory is that evolution requires geographic isolation of a small population. Yet people living in Africa shared a common stone technology with hominids in Eurasia and surely would have interbred with them. Any evolutionary change would have been muted by gene flow.
Another problem with Out-of-Africa is that it implies that a species which evolved in tropical Africa rapidly displaced cold-adapted Neanderthals in northern Europe during the coldest part of the last Ice Age. Acceptance of Out-of-Africa also requires us to accept the bizarre corollary that modern humans managed to cross the ocean to Australia as early as 60,000 bp, yet failed to walk into Europe until 43,000 bp.
It is more likely that culturally modern humans originated in the Americas. This theory was first proposed by Jeff Goodman in 1981. Only in America do we find evidence of advanced stone technology at early times. Holloman is not the only site in the Western Hemisphere at which human artifacts of great age have been found. At the Hueyatlaco site in Mexico, Virginia Steen-McIntyre and her colleagues have found advanced stone technologies dating to 250,000 bp.
It is possible that the opening and closing of the Bering Land Bridge has functioned as the pacemaker of human evolution over the last several hundred thousand years. Archaic Homo sapiens from Africa could have walked into America from about 189,000 to 130,000 bp. The critical period for evolutionary change was the last interglacial. From about 130,000 to 75,000 bp the land bridge was closed. Isolated from the rest of humanity, a relatively small population of people in the Americas could have evolved the intellectual capabilities of modern humans. When the land bridge opened again at 75,000 bp, there likely were one or more migrations back into Asia, with humans moving down the coast of Asia into Australia, eventually reaching both Africa and Europe.
The key to understanding where modern humans originated may lie in an obscure location in rural Oklahoma. The Holloman Pit is only a small part of a broad ridge of Pleistocene gravels 800 meters wide that extends linearly more than 12 kilometers. This area has never been excavated, yet it has a vast potential for discovery. If we do not look we shall not find.