Almost everything I've seen where they talk about intelligence, they are actually talking about education, and they also do it from a culturally-specific viewpoint to some degree or another. Actual intelligence is extremely hard to measure, and so it tends to be measured in terms of secondary characteristics - such as education. Because obviously if you are intelligent, you will have learned as much as you can, and that can be measured through education. But what of those who do poorly academically but are very clever in other ways? What of those who have reduced access to education, or poor quality education, or whose cultures do not value education as highly as those who make the tests?