If you were to compare a similar map from 1970 with the current one the notion of which came first would be much more clear. Before WWII IQ was pretty evenly distributed across the regions of Germany, but during the partition the IQs of children born in East Germany fell way behind those born in West Germany. And now with reunification and economic convergence IQ scores have converged too. Genetics may play a fairly large role in explaining outcomes for individuals, but if it affects measurable differences in outcomes between large groups the effect is small enough to be drowned out by other factors.