Rocks carved into ancient stone arrowheads or into lethal tools for hurling spears suggest humans innovated relatively advanced weapons much earlier than thought, researchers in South Africa say.
The researchers' finds, partially exposed by a coastal storm, suggest ancient peoples were capable of complex forms of thinking, scientists added.
"These people were like you and I," researcher Curtis Marean, a paleoanthropologist at Arizona State University in Tempe, told LiveScience.
Modern humans originated in Africa about 200,000 years ago, but when modern human ways of thinking emerged remains controversial. For instance, some researchers note that the first signs of complex thought such as art appeared relatively late in history, suggesting that genetic mutations linked with modern human behavior occurred as recently as 40,000 years ago.
Other scientists argue that modern human thought originated much earlier but that the evidence was largely lost to the rigors of time.
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