At http://anthropology.net/2013/07/26/the-role-of-climate-on-african-stone-… …. the blog author refers to a paper in the May 2013 issue of Nature Communications, 'Devolopment of middle stone age innovation linked to rapid climate change' where we learn the bigger blink of the eye (the last Ice Age, all 90,000 years) was punctuated by smaller winks of the eye (ups and down in temperature during that 90,000 years). Apart from the conscious attempt to transfer modern populist science into the palaeolithic world (global warming and cooling events) the paper does show that all is not as claimed as far as the Ice Age (the last of many) is concerned – it had lots of bumps, and ups and downs (all quite common knowledge but usually passed over in the broader picture show as purveyed in the textbooks designed for a public diet). Climate change here can be read as an 'event' of some kind – so we have the possibility of catastrophism (hidden behind the robes of respectable palaeo-climate studies). Basically, we are talking about dramatic changes in temperature and human migrations etc. The author observes that abrupt changes in rainfall in South Africa can be seen in the geology between 80,000 and 40,000 years ago – which tallies with similar changes elsewhere in the world at the same time. The researchers analysed river delta deposits over a period of 100,000 years (geological dates) and there were spikes when rainfall levels were sharply increased over a short time interval – before falling back again very soon afterwards (or within centuries from a geo-chronological standpoint). These wet periods coincided with the abrupt emergence of material cultures and new kinds of behaviour such as evidence of primitive agriculture, use of stone tools and bone, novel features of art and decoration, etc. In turn, changes in culture also occur with the onset of drier climate regimes. Palaeolithic cultural evolution appears to involve the migration and adoption of new ideas where novel technologies can be exchanged and explored.