' What Is Intelligence? By James Flynn

In his book What is Intelligence?, James Flynn outlines four paradoxes he associates with the Flynn effect—the intelligence paradox, the mental retardation paradox, the identical twins paradox, and the factor analysis paradox. But seen in the light of both neuronal intelligence and environmental intelligence, it becomes apparent that what Flynn is describing are not really paradoxes at all. Instead, what Flynn is describing are unjustified conflations of neuronal intelligence and environmental intelligence, conflations motivated by the scientific dogma that everything associated with human intelligence must be invariably linked to the human brain. Two of the paradoxes—the ones labeled the intelligence paradox and the mental retardation paradox—state the apparent incongruity that if the Flynn effect were literally true, then humans from one generation would be too implausibly dumb or too implausibly smart compared to humans
Think about incorporating questions dealing with baseball rules into an intelligence exam. If such questions had appeared on an exam in say the year 1800, no one at all, including the smartest people who then lived, would have been able to answer such questions correctly (other than by random luck). By contrast, if such questions were to appear on today’s intelligence exams, many individuals, including those of low-to-average intelligence, would be able to answer such questions correctly—baseball and its rules have become an established part of the human environment, their widespread presence and influence are now thoroughly encountered and absorbed by a large percentage of the population. As Flynn indicates, it would be only those with an IQ of around 75 or under who would have limited potential to answer such questions