Paleoanthropologists have characterized the properties of raw stone materials that were selected and used by Early Pleistocene tool-makers at an Acheulian site in the Ethiopian Highlands between 1.6 and 1 million years ago.
Handaxes made on side-struck flakes (a-c) and Kombewa flakes (d-f) from Melka Wakena, Ethiopia. Image credit: Tegenu Gossa & Erella Hovers, doi: 10.1007/s12520-024-02072-8.
“The two earliest stone tool complexes, the Oldowan and the Acheulian, are currently known to have appeared and proliferated within the East African Rift Valley,” said Hebrew University of Jerusalem’s Professor Erella Hovers and colleagues.
“The Oldowan (starting at 2.6 million years ago) represents a fundamental technological breakthrough involving obligatory use of percussive technology, using different types of lithic supports (e.g., cobbles; nodules, pebbles) as percussors for producing simple flakes.”
“The appearance of the Acheulian at 1.75 million years ago arguably marks major biological and behavioral transformations in hominin lifeways, frequently associated with increased cognitive capabilities.”
In their research, the authors focused on Melka Wakena, an early Acheulian site-complex located in south-central Ethiopian Highlands at an elevation of 2,300-2,350 m above sea level.
The site consists of several localities within approximately a 2-km stretch along the western bank of the Wabe River.
Preliminary investigations revealed faunal remains, including 15 species of large vertebrates with some animal bones bearing anthropogenic marks.
“Melka Wakena is one of the earliest known sites of human occupation in high altitudes,” the researchers said.
“Evidence suggests that early hominins made strategic choices based on factors such as rock suitability, durability, and efficiency.”
“Melka Wakena’s unique high altitude setting offers valuable insights into how early humans adapted to challenging environments.”
Using advanced digital imaging techniques, including 3D scanning and photogrammetry, the scientists produced highly detailed models that show the effect of use on the stone tools.
These models enabled precise analysis of wear patterns and surface alterations, revealing that raw material properties significantly impacted these alterations, even under identical usage conditions.
The findings suggest that early hominins carefully evaluated material properties when crafting tools, demonstrating a remarkable degree of technological foresight and adaptability.
“Our findings suggest that early humans were not just randomly picking up stones,” Professor Hovers said.
“They were making complex decisions about which materials would best suit their foreseeable needs, showing high level of planning ahead and cognitive sophistication.”
The results appear in the journal PLoS ONE.
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E. Paixão et al. 2025. Exploring early Acheulian technological decision-making: A controlled experimental approach to raw material selection for percussive artifacts in Melka Wakena, Ethiopia. PLoS ONE 20 (1): e0314039; doi: 10.1371/journal.pone.0314039
