Tyler Cowen notes that James R. Flynn — of the Flynn effect — has a new book out, What is Intelligence?: Beyond the Flynn Effect, that argues that we are much better at “freeing logic from concrete referents and reasoning about purely hypothetical situations” than previous generations:
In other words, people in earlier times really were stupider when it came to abstract thought, but this was primarily for environmental reasons. These people also had more daily, practical skills, again for reasons of practice. We in contrast receive daily workouts with hypotheticals, rapidly moving images, and spatial reasoning. So Flynn is suggesting that IQ isn’t more multi-dimensional than it may seem. The Flynn Effect gains are in fact concentrated in the most spatial and abstract versions of IQ tests.Flynn summarizes the “Dickens-Flynn” model, through which environment and IQ interact in multiplicative fashion. Smart people seek out environments which make them even smarter, and this helps reconcile the cross-sectional IQ data (adoption doesn’t change IQ so much) with the time series of increasingly higher IQ scores (environments are changing for everybody).