I am finishing up a large study on smart fraction theory (intellectual classes model). To this end, I reviewed all the empirical papers on the topic, and some historical ones. To save others and future-Emil the trouble of finding all these papers, here’s my collection. These are mainly collected by Google Scholar and following citing papers.

Proto-smart fraction theory:

The number of children with very superior ability is approximately as great as the number of feeble-minded. The future welfare of the country hinges, in no small degree, upon the right education of these superior children. Whether civilization moves on and up depends most on the advances made by creative thinkers and leaders in science, politics, art, morality, and religion. Moderate ability can follow, or imitate, but genius must show the way.

The social implications of exceptionally high ability and its interaction with the other factors that make for unusual achievements are considerably greater than the personal implications. The quality of a society’s culture is highly determined by the very small fraction of its population that is most exceptionally endowed. The growth of civilization, the development of written language and of mathematics, the great religious and philosophic insights, scientific discoveries, practical inventions, industrial developments, advancements in legal and political systems, and the world’s masterpieces of literature, architecture, music and painting, it seems safe to say, are attributable to a rare small proportion of the human population throughout history who undoubtedly possessed, in addition to other important qualities of talent, energy, and imagination, a high level of the essential mental ability measured by tests of intelligence.

[Added: Jensen in fact discussed this back in 1969 too, see Dalliard’s 40-year anniversary review of Jensen’s famous article]

La Griffe du Lion’s writings

These began the modern writings on the topic. http://www.lagriffedulion.f2s.com/, archived at IA and archive. There are 2 articles in particular:

Academic papers