Prehistoric technology Ground and polished stone tools continued to be created and used during the Neolithic period. Numeric record keeping evolved from a system of counting using small clay tokens that began in Sumer about 8000 BC. The Stone Age developed into the Bronze Age after the Neolithic Revolution. The Neolithic Revolution involved radical changes in agricultural technology which included development of agriculture, animal domestication, and the adoption of permanent settlements. The Bronze Age is characterised by metal smelting of copper and its alloy bronze, an alloy of tin and copper, to create implements and weapons. Polished stone tools continued to be
Neolithic and Bronze Age rock art in the British Isles might have been induced by the use of hallucinogenic drugs, evidence for which exists from Neolithic and Bronze Age Europe. This idea was first applied to the petroglyphs on the Neolithic monuments of the British Isles by David Lewis-Williams and T. Dowson. They noted that the depiction of phosphenes could appear independently in different areas due their common basis in the human nervous system. Lewis-Williams and David Pearce expanded on this idea in their book "Inside the Neolithic Mind". Bradley extended these ideas to suggest that the circular designs on open air petroglyphs might have represented a pathway that led