It's uncomfortable to consider, but there is strong evidence to suggest that the brains of Australian aboriginal people differ in significant ways from their Caucasian bretheren. One study found the aboriginal visual cortex to be significantly larger than the Caucasian equivalent [0], possibly as an adaption to Australia's (visually) vast open spaces. The same study found the Caucasians had significantly larger parietal lobes and cerebellums - the same structures mentioned in this article. Another study found that Caucasians have significantly larger brains on average compared to those of aboriginals [1].
There's also evidence to suggest that modern humans from India [2] have contributed to the Australian gene pool for millennia (long before the arrival of the British), so more dramatic cranial differences may have already been averaged out.
EDIT: deleted figure mis-remembered from an unrelated study.
There's also evidence to suggest that modern humans from India [2] have contributed to the Australian gene pool for millennia (long before the arrival of the British), so more dramatic cranial differences may have already been averaged out.
EDIT: deleted figure mis-remembered from an unrelated study.
[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1261675/ [1] https://www.ncbi.nlm.nih.gov/pubmed/6926391 [2] http://www.pnas.org/content/110/5/1803