This adds more evidence that modern behavior developed over time during the Middle Stone Age rather than after our ancestors migrated from Africa to Europe, as some scientists have thought.

Researchers from the University of Colorado at Boulder discovered that the delicate technique — called “pressure flaking” — was used by anatomically modern humans at Blombos Cave in South Africa during the Middle Stone Age. Previously, the earliest evidence of pressure flaking was from 20,000 years ago in France and Spain.

“This finding is important because it shows that modern humans in South Africa had a sophisticated repertoire of tool-making techniques at a very early time,” study co-author Paola Villa, a curator at the University of Colorado Museum of Natural History, said in a university news release.

“This innovation is a clear example of a tendency to develop new functional ideas and techniques widely viewed as symptomatic of advanced, or modern behavior,” she added.

Pressure flaking “takes place when implements previously shaped by hard stone hammer strokes followed by softer strikes with wood or bone hammers are carefully trimmed on edges by directly pressing the point of a tool made of bone on the stone artifact,” according to background material in the study. Many stones — with the exception of jasper, obsidian and high-quality flint — also had to be heated before pressure flaking, researchers noted.

This technique enables better control of the sharpness, thickness and overall shape of two-sided items such as spearheads and stone knives, Villa explained.

The study appears in the Oct. 29 issue of Science.

CAIRO – Rich Egyptians living 3,500 years ago may have been walking around with the same clogged arteries that modern Americans now battle, according to a presentation Monday at the American Heart Association’s annual meeting.

A group of scientists said that, on a whim, they performed a computerized tomography (CT) scan on a collection of 22 mummies housed at the Egyptian National Museum of Antiquities in Cairo to see if they too suffered from the plaque build-up in arteries that lead to coronary artery disease.

“We didn’t believe it was going to be so intense,” said Adel H. Allam, the lead author of a letter to the editor published Tuesday in the Journal of the American Medical Association. “We thought that we would find it, but maybe very rarely, and we thought that if we did find it, it wouldn’t be so severe.”

The plaque was, of course, long gone. The mummies lived between 1981 B.C. and 364 A.D., and only 16 of the mummies had heart tissue left. However, doctors could see evidence of advanced atherosclerosis (plaque build-up that causes hardening of the arteries) by looking for calcium deposits in a CT scan used to diagnose people today.