It may have been a lazy, 'why bother?' attitude that led to the downfall of an early species of human, according to new research.

Findings from the Australian National University after an archaeological excavation in Saudi Arabia found Homo erectus tended to do the bare minimum to get by, while other species of human were inclined to put in the effort.

They used "least-effort strategies" for tool making and collection of resources, as opposed to Homo sapiens and Neanderthals, who would climb mountains and haul materials over dozens of kilometres to ensure they had quality goods, the research showed.

Homo erectus, in contrast to the more advanced species, tended to use a single "generic" tool for almost all purposes.

In a similar vein, this particular group also simply used whatever was nearest to their camp at Saffaqah — which is about 200 kilometres west of Saudi Arabia's capital, Riyadh — likely even stone that had broken off a nearby rocky outcrop and rolled down the hill, according to lead researcher Ceri Shipton.

There was better material at the top of a nearby hill, if only they had made the trek. ( Supplied: ANU )

"They knew it was there, but … they seem to have thought, 'why bother?'," he said.

The major problems arose when the environment turned into a desert around them.

Because of their reluctance to journey and put in the effort to find the best possible resources, when the rivers that were flowing across the region dried up, they could not find the increasingly rare water.

"They never strayed very far from fresh water sources," Dr Shipton said.

Dr Ceri Shipton said Homo erectus often did the bare minimum to get by. ( Supplied: ANU )

"We also found that in the technology they were using to make the stone tools, they were very conservative. They used the same strategies for making the tools in the face of changing environments.

"They don't appear to have been adapting very much ... and when the environment got too difficult for them, when it got very dry, they just went extinct."

Dr Shipton said the demise of Homo erectus came down to an inability plan ahead.

"They were very short term in their view," Dr Shipton said

"They would be just planning just a few hours, perhaps a day ahead at most, whereas Homo sapiens and Neanderthals [did] things like target seasonal migration.

"So they're planning perhaps for the year ahead."

The study was published in PLOS One.