The san hunter-gatherers of southern Africa establish social networks by exchanging gifts, often glass or ostrich-eggshell beads, strung into a necklace or sewn onto a bag or hat. The gifts help secure future favors, says anthropologist Stanley Ambrose of the University of Illinois in Urbana-Champaign. As one San man told a researcher to whom he gave a gift, "It's free! It's yours! And don't you forget it!" According to Ambrose, such gift giving may have been established more than 40,000 years ago. He has found ostrich-eggshell beads of that age in Kenya, which rank among the world's oldest ornaments and may have given early humans in Africa an edge over their competitors.
Ambrose has been working at a rock shelter called Enkapune Ya Muto, or Twilight Cave, in Kenya's Rift Valley. There, among thousands of stone tools, he discovered the remains of an ostrich-eggshell bead workshop. He found nearly 600 ...
