Fact is, by traditional measures, children today are much smarter than earlier generations:
IQ tests are updated periodically. For example, the Wechsler Intelligence Scale for Children (WISC), originally developed in 1949, was updated in 1974, in 1991, and again in 2003. The revised versions are standardized to 100 using new standardization samples. In ordinary use IQ tests are scored with respect to those standardization samples. The only way to compare the difficulty of two versions of a test is to conduct a study in which the same subjects take both versions. Doing so confirms IQ gains over time. The average rate of increase seems to be about three IQ points per decade in the US on tests such as the WISC. The increasing raw scores appear on every major test, in every age range and in every modern industrialized country although not necessarily at the same rate as in the US using the WISC. The increase has been continuous and roughly linear from the earliest days of testing to the present.[9] Though the effect is most associated with IQ increases, a similar effect has been found with increases of semantic and episodic memory.[3]
Ulric Neisser estimates that using the IQ values of today the average IQ of the US in 1932, according to the first Stanford–Binet Intelligence Scales standardization sample, was 80. Neisser states that "Hardly any of them would have scored 'very superior,' but nearly one-quarter would have appeared to be 'deficient.'" He also writes that "Test scores are certainly going up all over the world, but whether intelligence itself has risen remains controversial."[9]
Flynn effect, Wikipedia