Arguably, the surprise is in the fact that Australia and New Zealand are also in this top bracket. A prejudice of low expectations holds that the fat and happy Anglosphere is also dumb, compared with the Asians and a few Baltic standouts. Not necessarily so, though the U.S. has only middling scores in this study; the U.K. did somewhat better.
First of all, yay for us! New Zealand is living up to our own story of being small but nimble and smart, a story Ferguson tells for Asia:
Commodity prices are up, but the most enduring natural resource is the human mind. That is the essential explanation for many of Asia's great modern successes, and the premium for knowledge is only growing with advances in information technology.
I've long thought that's what we had going for us. Maybe I've just been hanging out with the right crowd, and reading too much Idealog.
Secondly, I've never come across the "prejudice of low expectations" about our "fat and happy Anglosphere" - although I am secretly (or not so secretly) very happy but not surprised that we are, on aggregate, smarter than the US.