Some notes and speculations about various topics. ||| Gegenwärtig - vorübergehend -
wohl eher eine Gedanken- und Entwurfsammlung als ein Naturwissenschaftsblog. Die effektive Aufspaltung dieses Blogs in einen Naturwissenschaftsblog und einen rein spekulativen Blog wird voraussichtlich im Laufe dieses Jahres (2019) statt finden.
In the past different researchers have come to diverging cognitive ability estimates for people in Africa and of African descent. The paper tries to check the validity of past results by comparing them with outcomes of two new psychometric test studies from East and South Africa; with results from student assessment studies; with predictions based on those variables which, outside Africa, correlate most strongly with intelligence; and by comparing them with further indicators of cognitive ability (descriptions of everyday life and human accomplishment). Integrating these cognitive ability measures with the application of several corrections (due to the higher age of students in Africa, lower African school enrollment, selectivity of samples and higher African secular IQ rise), the best guess for an African average is IQ 75. Finally, possible environmental and genetic (evolutionary, therefore past environmental) causes are discussed and suggestions are given how to enhance cognitive development in African countries.