SOMEWHERE in our history is a stone-age Steve Jobs. His invention changed the world - and now scientists say he may not even be a proper modern human.

A recent analysis of the world's oldest known technology - stone-tipped throwing spears - shows they actually predate the earliest known humans by some 85,000 years.

The implications are mind-blowing, scientists say.

Was the creator of this deadly "iStone" an equivalent of the Apple genius who was several steps back on the evolutionary chain that led us down from the trees?

Or have modern humans - Homo sapiens - actually been around much longer than originally thought?

The study, published in online science journal PlosOne, examines a set of newly discovered spearheads from Ethiopia. They appear to date from 280,000 years ago.

The find in the district of Gademotta suggests the "stone-age Steve Jobs" - who would have been a lot more familiar with apples than, er, Apple - was a member of the pre-modern species Homo hiedelbergensis more commonly known as Heidelberg man (and Heidelberg Woman) who lived in Africa, Europe and western Asia about 600,000 years ago.

The stone tools suggest the species was much more crafty and clever than previously believed.

A postdoctoral researcher at the University of California at Berkeley's Human Evolution Research Center, Dr Yonatan Sahle, said he and his team determined that the spears were made from obsidian found near the site.

The volcanic glass is difficult to craft.

They had to shape the spear point and form a recess for a shaft. These then had to be carefully strung and glued to the timber shafts.

And these spears were designed to be thrown, not thrust.

Even today, both building and using such spears involves skills requiring a good degree of knowledge, experience and concentration.

The find suggests that human intelligence predates our modern body shape.

Heidelberg man did look very human, though he was particularly tall and muscular.

"Technological advances were not necessarily associated with anatomical changes," Sahle said. "The advances might have started earlier."

The first key may have been the availability of good quality materials in the region, he said.

"Second, a bigger population was supported at the site. With more individuals around, there would have been a greater chance for the spread of innovative ideas. If there was indeed a Steve Jobs-type in the mix, he would have been able to influence more individuals and perhaps even created a prehistoric spear-making assembly line of sorts.

"Thirdly, there was a mega lake at the site. It might have attracted stable occupations there, further fuelling technological advances."