On average, formal education is more likely than not to be correlated with higher intelligence because it generates opportunities to learn, but it’s not an isolated determinator, and widely varying academic standards don’t always guarantee graduates make good use of that opportunity.
However, with respect to that Wiley (a text-book mill which to my mind screams conflict of interest) article’s abstract - and acknowledging that I’m not buying the article, so maybe it does address this - IQ tests are, respectfully, a shit show, and I take any modern study that presents it otherwise with a shaker of salt at best.
http://www.oupcanada.com/catalog/9780199585595.html
The question ‘What is intelligence?’ may seem simple to answer, but the study and measurement of human intelligence is one of the most controversial subjects in psychology. For much of its history, the focus has been on differences between people, on what it means for one person to be more intelligent than another, and how such differences might have arisen, obscuring efforts to understand the general nature of intelligence. These are obviously fundamental questions, still widely debated and misunderstood. New definitions of intelligence and new factors affecting intelligence are frequently being described, while psychometric testing is applied in most large industries.
https://select.nytimes.com/2007/09/14/opinion/14brooks.html
And finally a free in-depth article for the curious. Section 6 (pp. 95 to 97): Summary and Conclusions is readily accessible to a non-technical audience…
