Stone age artifacts discovered at a site in Armenia have shown how innovative humans were in terms of technology 325,000 years ago, according to a new study.

Published in the journal Science, researchers from the University of Connecticut examined thousands of stone artifacts retrieved from Nor Geghi 1, a unique site preserved between two lava flows dated from 200,000 to 400,000 years ago. The archaeological material was found in layers of floodplain sediments and ancient soil between the lava flows.

Analysis of the artifacts showed that human technological innovation occurred intermittently throughout the Old World, rather than spreading from a single origin.

The findings challenges the long held theory that human technology developed and spread as human populations moved. Experts thought more advanced technology was invented in Africa and spread to Eurasia, replacing older tools in the process.

Researchers found two distinct technologies at the site: biface technology, such as hand axes, is associated with the Lower Paleolithic era, while the more advanced Levallois technology, a stone tool production method, is thought to have come from the Middle Stone Age in Africa and the Middle Paleolithic in Eurasia.

To the researchers' surprise, these stone tools suggest simultaneous use of both biface and Levallois technology.

"The combination of these different technologies in one place suggests to us that, about 325,000 years ago, people at the site were innovative," lead author Daniel Adler said in a statement.

And after comparing archaeological data from sites in Africa, the Middle East, and Europe, researchers believe that this evolution was gradual and intermittent, and that it occurred independently within different human populations who shared a common technological ancestry.

According to Adler, their findings indicate that Stone Age people were in fact flexible and variable in terms of their technology, highlighting the "antiquity of the human capacity for innovation."