By Aulden Foltz
Two Stanford researchers are using mathematics to model the extinction of Neanderthals. Biology professor Marcus Feldman and Applied Physics Ph.D. student William Gilpin collaborated with Kenichi Aoki of Meiji University to release a paper this past month using a measure of “culture” as the distinguishing factor between humans and Neanderthals.
The new paper took an interdisciplinary approach in order to explain why humans, not Neanderthals, became the prevalent species.
According to previous research, modern humans migrated to Europe around 45 thousand years ago. At the time, Neanderthals had already lived in Europe for hundreds of thousands of years and had established much larger populations than the migrating humans.
In the past, there has been academic debate over whether humans and Neanderthals interacted. Research in the past few years, however, has revealed that modern day humans outside of Africa have approximately 1.5 to 2.1 percent Neanderthal DNA in their genome, meaning that there must have been interaction and coexistence. This raised the question of why humans surpassed Neanderthals.
“Everybody’s hypothesis has been that we were probably smarter [than Neanderthals], in some respects,” said Shripad Tuljapurkar, a Stanford biology professor who commented on the research. “What this paper does is it actually attempts to get fairly precise about explaining what this smartness is.”
Feldman and Gilpin do not assume that humans had higher cognitive function than Neanderthals. Instead, they express the “smartness” of humans through what they call “culture.” Feldman and Gilpin use this term in a very specific way.
Drawing from paleobiological, archaeological and anatomical literature, Feldman and Gilpin highlight a number of skills humans developed before or at a greater complexity than the Neanderthals. They focus mainly on complex language and tool development. These skills, rather than cognitive function or artistic ability, would have directly affected human population size.
“Because of [human’s] advanced culture, their population is able to grow faster, the environment is able to support more of them, and the result is that the culture itself allows modern humans to overwhelm the Neanderthal,” Feldman said.
In the future, Feldman and Gilpin hope to add spatial effects to their models since human-Neanderthal interactions occurred over massive areas and timescales. Both the physical migration of humans and the spread of ideas and culture need to be taken into account.
By borrowing mathematical techniques from classical systems in physics, Feldman and Gilpin were able to come up with a possible explanation for an otherwise unexplained phenomenon. Much of the flexibility of their research relies on the fact that each member of the research team comes from very different backgrounds in academia.
Feldman focuses his research on theoretical biology, while Gilpin has a background in classical physics. Their colleague, Aoki, works on a Japanese Science Foundation project called The Replacement of Neanderthals by Modern Humans, which funds archaeological, paleontological and anatomical projects.
“The nice thing about being a professor here at Stanford is how easy it is to do this kind of interdisciplinary research,” Feldman said. “We don’t build walls around departments.”
Contact Aulden Foltz at afoltz ‘at’ stanford.edu.