Ostrich beads indicate early symbolic thought 18:25 31 March 04 NewScientist.com news service Stone Age beads revealed by archaeologists on Wednesday could be the strongest evidence yet that humans developed sophisticated symbolic thought much earlier than once thought. The ostrich egg beads and numerous other artefacts, including ochre pencils, carved bone and stone tools, were recovered from the Loiyangalani River Valley, in Serengeti National Park in Tanzania. The archaeologists who discovered the relics have yet to date them precisely, but believe they originate from the African Middle Stone Age - between 280,000 and 45,000 years ago. This is because they...