When we started being really inventive is not known. Cave art, burial rites, weaponry, jewelry are all studied items. Now 71,000 year old arrowheads are adding to the puzzle:-http://blogs.scientificamerican.com/observations/2012/11/07/oldest-arrowheads-hint-at-how-modern-humans-overtook-neandertals/?WT_mc_id=SA_DD_20121108-WSJ thorough article:-http://online.wsj.com/article/SB10001424127887323894704578105004000070778.html?KEYWORDS=Gautam+Naik-We had a big brain long before, about 200,000 years ago. Apparently we had to learn to use it.

Adding to the arrow heads, now spear tips from 500,000 years ago:-http://blogs.scientificamerican.com/observations/2012/11/15/human-ancestors-made-deadly-stone-tipped-spears-500000-years-ago/

More evidence of southern African cultural development:-http://phys.org/news/2012-12-africa-homo-sapiens-techies.html