[simonh]

Interesting, thanks. I think the fact that some of these advances are very spread out doesn't necessarily mean they are unrelated. It would have been very slow going in terms of change and iteration back then.

Prefrontal Synthesis is a lot more recent and generates a lot of material evidence (in comparison) so I think it's easier to see that there was a common cause behind the subsequent developments in material culture, which fall under the umbrella of Behavioural Modernity.