Scientists have found evidence that human ancestors used stone-tipped weapons 200,000 years earlier than once thought, findings that may change notions about the capabilities of prehistoric people.

Spears topped with stone points were most likely used for hunting large game and self-defense and were an important advance in weaponry, according to Jayne Wilkins, lead author of the paper Thursday in the journal Science. The points came from one of the Stone Age archaeological sites in South Africa called Kathu Pan 1, and were used a half-million years ago.

Researchers first thought the early humans were using sharpened wooden spears or stone hand axes, Wilkins said. The steps required to put a sharp-tipped stone at the end of a wooden spear, called hafting, means these ancestors had to engage in planning and other goal-driven thought processes long before a hunt took place, she said.

"This expands the range of behavioral complexity known in human ancestors living 500,000 years ago," said Wilkins, a PhD candidate in the Department of Anthropology at the University of Toronto, in a Nov. 13 email. "The amount of fore-planning and goal-oriented behavior required for collecting stone, wood and bindings for hafting indicate capabilities much greater than was previously known. It also shows that stone-tipped spears were being used by the ancestors of both modern humans and Neanderthals, so the technology is probably not an independent invention nor something one group learned from the other."

The spears were an improvement because the hunters could get further out of harm's way and were more likely to make a successful kill, she said.

The stone tips were recovered between 1979 and 1982 during excavations. In 2010, researchers dated the site to about a half-million years ago.

In the study, researchers replicated the stone points, attached them to spears and then shot them at a dead animal using a calibrated crossbow. The damage to the researchers' stone points was similar to that seen on the 500,000-year-old points, Wilkins said. The stone points also fit the size and shape of Stone Age points used as spear tips.