As this book was going to press, I was sent a paper that advances our knowledge of what goes on in the minds of people today so that they score much better on Raven’s than previous generations. Hitherto my explanation of why similarities scores had increased was more adequate than my explanation of why Raven’s scores had increased. As to the latter, I could say only that the utilitarian habits of mind of our ancestors tied their use of logic to the concrete world of physical objects, while the scientific ethos we live in made using logic on symbols and abstractions (often far removed from the concrete) more congenial.

Fox and Mitchum have written a paper that adds substance to the explanation of Raven’s gains: mainly that Raven’s (they used the Advanced Progressive Matrices Test) scores between generations rise on items that are further and further away from taking images at face value and more toward ascribing them symbolic significance. In my system, the sociological key is that utilitarian manipulation of the real world means that the representational image of objects is primary. If you are hunting, you do not want to shoot a cow rather than a deer. If a bird is camouflaged by being in a bush, you flush it out so its shape can be clearly seen. On the other hand, what Raven’s often asks you to do is to divine relations that emerge only if you “take liberties” with the images presented.