For decades, the human story was one told through signs of modernity—art, tools, burials—found only after Homo sapiens left Africa. Recent discoveries pushing back the date of departure are helping to change that narrative, as are three new studies in Science. Together, they describe the earliest stone tools of their kind in East Africa as well as the earliest evidence for long-distance transport of raw materials in the region, per Science News. Researchers previously believed the Early Stone Age marked by large, primitive tools (hand axes and cleavers) made way for the Middle Stone Age and its smaller tools (spearpoints and blades) around 280,000 years ago. But stone tools found in Kenya's Olorgesailie Basin show hominin groups—it's not clear which species is responsible—had developed these more advanced tools approximately 320,000 years ago.
"We see a smaller technology, a more diverse series of stone tools … designed for specific purposes," researcher Rick Potts tells NPR. An expert not involved in the study says the tools are so "prepared and retouched" they suggest the Middle Stone Age likely started even earlier. What drove it? Microscopic and chemical analyses of the region's soil show the landscape was rapidly shifting between wet and dry conditions, meaning hominins might have been forced to adapt. But as the technology also coincides with the emergence of Homo sapiens in Africa, it's possible that the human mind deserves credit. The tools themselves suggest the development of trading networks, too. Some were made of rocks carried from 55 miles away, says Potts. Others were made of obsidian from as far as 30 miles away, per the Conversation. (These stone tools are also making waves.)