Serbia has a much stronger affinity with Russia, Croatia is in Catholic Europe, while Slovenia seems more like Northern European nations than Croatia.
You have to go read the whole thing. He discusses a cultural map of the world, based on two scales: traditional values vs. secular/relational values; and survival values vs. self-expression values.
He then goes on to discuss the Peter Turchin, et al paper that I’ve seen referenced on several blogs. It’s the paper that develops an index of social complexity. I think of it as something like an IQ measure that operates at a cultural level.