Can the Flynn Effect Dwindle As the IQ Rises?
All IQs in the following discussion are based upon a standard deviation of 16. In arguing that the Flynn Effect cannot be dependent upon IQ, I assumed that the Flynn Effect acts uniformly over all age groups. But supposing it isn’t. Suppose that someone who today has a deviation IQ of 143 (present-day ratio IQ of 150) actually only has a present-day ratio IQ of 125 (present-day mental age of 20). And someone today with a deviation IQ of about 174 (equivalent ratio IQ of 200) really only has a present-day ratio IQ of 150 (present-day mental age of 24). In other words, suppose that the distribution curve for the upper half of the year-2002 distribution for intelligence is only half as wide as it was in 1916, with a standard deviation of 8 instead of 16. After all, if we measure adult IQ’s, and since 1986, even children’s IQs, only with deviation IQs (frequencies of occurrence,) we have no idea what their actual levels of capability are. The average present-day young adult (present-day IQ
