As cranial capacity gets smaller the tools get simpler.
And apparently other skills increase.
Aborigines:
They seem to have better visual memory than other populations, having a much larger visual cortext.
Australian Aborigines have long been famous for their ability to navigate the trackless wastes, to find water holes and locate animal lairs. Modern testing has shown that this is because they excel in what is called "visual memory." On average, they perform about 50 percent better than whites when asked to recall what they saw in a room or picture.
Now Clive Harper, a professor of pathology in Sidney, Australia, reports that the visual cortex, which processes visual information, is about 25 percent larger in Aborigines than in whites and has more nerve cells. He points out that no one really knows how the visual cortex works, but the difference in size suggests inherently superior spatial ability. However, racial differences in brain structure are a very unfashionable area of study, and Prof. Harper has been unable to publish his work in any scientific journal. Editors are "anxious that this was going to be seen as some form of discrimination," says Prof. Harper. The organizers of a conference in the United States also refused to let him present his work. [Alasdair Palmer, The Difference, Sunday Telegraph (London), Nov. 19, 2000.]
It is easy to scorn the unwillingness of editors to deal with scientific fact, but their terror is easy to understand. Overall, the Aborigine brain is only about 85 percent the size of the European brain, and the skull is about twice as thick as in other races.....If, given their generally smaller brains, the Aborigine visual cortex is exceptionally large, this would mean other areas of the brain are correspondingly smaller. This would conform entirely with the low performance levels Aborigines show in other mental abilities.
How do you think you would fare against an aborigine in a visual recall test or memory mapping spatial pathways? Different populations have different areas of strength.
It seems to me that tool formulation (and technology in general) is affected by environment, weather, population differences, competition, access to previous acquired knowledge etc. and probably many other factors that I haven't mentioned.
This guy looks pretty close
