Human development over time

The theory, science, and investigation of human evolution and development have long been sources of debate and dispute. From Charles Darwin’s On the Origin of Species to the Creation Museum in Petersburg, Kentucky, many views abound. Some come squarely within the consensus of scientific thought and others from way off on one fringe or another.

Consensus has it that human beings have not always looked like the beautiful and handsome creatures we saw in the mirror this morning. We sit here today as members of the species Homo sapiens. 

What is a species?

The website Biology Online defines “species” as a group of organisms with common characteristics that can mate with each other to produce fertile offspring. New and different species emerge from time to time, and they may overlap in time and geography.

Homo sapiens species is not the first and only species that appears on our family tree. Just how many species appear on our family tree is up for debate along with everything else, including when and where each species lived and how one transitioned to the other.

Our family tree of species

Scientists debate, as we will see, just how many species of pre-you-and-me humans have existed. However, according to the Smithsonian Museum of Natural History most scientists agree that there have been 20 species of early humans. Does that number surprise? Some of these names will be more common than others, but here’s the Smithsonian’s version of the “consensus,” from oldest to youngest.

  • Sahelanthropus tchadensi
  • Orrorin tugenensis
  • Ardipithecus kadabba
  • Ardipithecus ramidus
  • Australopithecus anamensis
  • Australopithecus afarensis
  • Kenyanthropus platyops
  • Australopithecus africanus
  • Paranthropus aethiopicus
  • Australopithecus garhi
  • Homo habilis
  • Paranthropus boisei
  • Australopithecus sediba
  • Homo rudolfensis
  • Homo erectus
  • Paranthropus robustus
  • Homo floresiensis
  • Homo heidelbergensis
  • Homo neanderthalensis
  • Homo naledi

 

There have been other candidates for that illustrious list that have been rejected for one reason or another. One of them is Homo capensis — sometimes referred to as Boskop Man.

Introducing Homo capensis, aka Boskop Man

Two Afrikaner farmers found hominid fossils near Boskop, South Africa in 1913 while digging a drainage ditch. The bones they found included parts of a skull. The farmers took the bones to Frederick W. FitzSimmons at the Port Elizabeth Museum at the tip of South Africa. Paleontologist S. H. Haughton investigated them and reported his findings to the Royal Society of South Africa in 1915. From there, European anatomists became interested, including Scottish scientist Robert Broom.

Consensus has it that human beings have not always looked like the beautiful and handsome creatures we saw in the mirror this morning.

Broom published a paper called “The Evidence Afforded by the Boskop Skull of a New Species of Primitive Man (Homo capensis)” in The Anthropological Papers of The American Museum of Natural HistoryIn that paper, Broom proposed that the Boskop Man was a new and distinct species of ancient humans that lived in Southern Africa some 10,000 years ago.

What was striking about Broom’s work on the Boskop Man skull fragments found, and other findings that were consolidated with it, was the calculations of Boskop Man’s brain capacity.

What should we make of Boskop Man’s big brain?

Broom estimated that Boskop Man’s skull had a brain capacity of 1,930 cubic centimeters, over one-third larger than the brain capacity of modern humans (1,400 cubic centimeters). In addition to that, the other bone fragments suggested Boskop Men had small faces akin to children. Boskop man’s face made up just one-fifth of his cranium; by comparison, a modern human adult’s face takes up one-third of our cranium.

Boskop enthusiasts were drawn to the notion that a small enclave of early hominids had superior intelligence (based on their larger brain capacity and a prefrontal cortex that would have been 53% bigger) but had not prevailed as the dominant human species.

A December 2009 Discover magazine article titled “What Happened to the Hominids Who May Have Been Smarter Than Us?” excerpted a portion of the book Big Brain by Gary Lynch and Richard Granger. Lynch and Granger were experts in neuroscience who had many publications about memory and brain activity. Neither were anthropologist or archaeologists. The authors posited the notion that Boskop man represented an isolated superior human species.

We’re drawn to the idea that we are the end point, the pinnacle not only of the hominids but of all animal life. Boskops argue otherwise. They say that humans with big brains, and perhaps great intelligence, occupied a substantial piece of southern Africa in the not very distant past.

Lynch and Granger speculated that a typical Boskop would have had a genius-level IQ of 149, and that 15 to 20% of Boskops might have IQs over 180. We, to Boskops, would look like mere primitives. So, as posed in the question, what happened to them? As the writers put it: “Why didn’t they outthink the smaller-brained hominids like ourselves and spread across the planet?”

Perhaps the reason has to do with when they existed. The human brain is a sort of central processing unit operating on multiple memory disks, some stored in the head, some in the culture. Lacking the external hard drive of a literate society, the Boskops were unable to exploit the vast potential locked up in their expanded cortex.

If this is true then, perhaps, they were born just a few millennia too soon.

Not everyone believes ‘Homo capensis’ existed as an isolated superior species

The neuroscientists’ assessment of Boskop man and his evolutionary relevance was not unanimous, though. Paleoanthropologist John Hawks, even before reading the book, attacked the notion of the Boskops as a superior early human.  John Hawks is an associate professor of anthropology at the University of Wisconsin–Madison. Lynch and Granger’s idea was drawn, he suggested, from ideas that had been rejected, disregarded, and ignored for decades, since the 1950s. Why, then, the revival?

Hawks speculated that the source was not science, so much as science fiction. In 1958, author Loren Eiseley published a collection of writings called The Immense Journey. It included an essay about Boskop Man. In language that would be echoed in Big Brain, he wrote: “What we can say is that perhaps the unloosed mechanism ran too fast, that the biological clock had speeded them out of their time and place — a time which ten thousand years later has still not arrived. This, then, was the logical end of complete foetalization: a desperate struggle to survive among a welter of more prolific and aggressive stocks.”

Hawks “hate[d] to think that the theme of a 2008 book” came from a 1958 essay, but had no other explanation. To his paleontologist’s mind, there was no way to estimate a fossil’s IQ, and no foundation for the notion that humans’ brain functions had shrunk in the last 10,000 years.

Then he read the book, or some of it anyway. Hawks posted his impressions on his blog at johnhawks.net, including the assessment that “The portrayal of “Boskops” in the Discover excerpt is so out of line with the anthropology of the last forty years, that I am amazed the magazine printed it.

As it turns out, Discover amended the page excerpting the text of Big Brain to refer specifically to Hawks’ contrary opinion.

Other theories about homo capensis

For many people, including Dr. Ed Spencer and former member of the Legal Department at the World Bank, Karen Hudes, Boskop Man is the tip of an enormous iceberg. Spencer and Hudes suggest, as recently as in a 2014 podcast on Canarycryradio.com, that the rejection of Boskop superiority is a cover-up.

Spencer and Hudes suggest that Boskop Men were another humanoid race on Earth that constructed megalithic structures around the world, and prison cells in South Africa to keep other human species as “their pets.” Spencer and Hudes also query whether ancient Egyptian Pharaohs may have been Homo Capensis themselves, including the Pharaoh Akhenaten who, they posit, may actually have been Abraham or Moses.

There is a lot of room between Sahelanthropus tchadensi and Homo naledi. Lots of space and time for the finding, losing and re-writing of history and inquiry. Should Boskop Man — Homo capensis — be written into the family tree set out by the Smithsonian. The consensus would say no. But contrary voices exist.

A deeper dive — Related reading from the 101: