Population growth, spread responsible for human advancement

May 3 (UPI) -- Researchers at Stanford University have identified population growth and spread as a possible cause for early human advancements such as explosions of tool use.

Previous theories regarding why there was a significant increase in the use of new tools, art and other cultural artifacts from the Middle to the Upper Paleolithic period credited climate change, which forced prehistoric humans to innovate or die off.

The Paleolithic period was marked by periods of slow change and then bursts of cultural innovation.

The research was conducted in the lab of Marcus Feldman, a professor of biology at Stanford, along with Oren Kolodny and Nicole Creanza, both of whom are post-doctoral fellows at Stanford.

"Those cultural bursts have been taken as evidence of an external change," Creanza said in a press release. "But to some extent, Oren, Marc and I felt that the simplest explanation could be that culture itself is capable of behaving in a punctuated fashion."

The research combined a previous study showing the combination of three kinds of advancements -- lucky leaps theory, extensions of lucky leaps and the loss of ideas could -- have directly led to bursts of innovation, with two new components.

The two new components were migrations between distinct populations and that certain major innovations helped grow the population.

The updated model made predictions that qualitatively validate what archaeologists know about cultural evolution in the Paleolithic period.

Researchers theorized that when population sized are small and migration is rare, a pattern of cultural booms and busts will occur. Occasional travel may bring new ideas to set off a boom, but without more new ideas, innovation can be lost over time.

However, innovation that encourages population growth can have lasting effects.

"We don't think that whenever we get a qualitative pattern that looks like the archaeological record, this is what necessarily happened," Kolodny said. "But it is a proof of concept that it could have happened this way."

The study was published in Royal Society Interface.