Stone Age superglue: a first sign of intelligence?   Wired - January 30, 2015
Researchers who reverse-engineered an ancient superglue have found that Stone Age people were smarter than we thought. Making the glue, originally used on 70,000-year-old composite tools, clearly required high-level cognitive powers. Anthropologists usually use symbolic art as the benchmark for modern cognition, but making the glue was an equally profound accomplishment. The archaeologists took design cues from stone tools found during a decade of excavation at South AfricaÕs Sibudu Cave site. The stones were still covered with traces of an iron-rich red pigment and acacia gum, a natural adhesive found in the bark of acacia trees. Acacia gum was almost certainly used to attach the stones to wooden shafts, but researchers have debated the pigment's role. Some suggested that it was decoration. The Witersrand team suspected a more functional use.