It’s not an incidental correlation—something that happened to exist at the same time as contemporary societies were being built. Cultures all over the world came to the conclusion that physical discipline produced better behaved kids. Europeans only changed their view in the last generation or so, and in Asia, it’s still the dominant view.

By contrast, cultures that stopped using physical discipline are almost universally in decline. On the European continent, for example, post-Christians who don’t use physical discipline are being outcompeted by Muslims who do.