Researchers at Duke University in North Carolina published in Current Directions in Psychological Science, they describe how they sifted through nearly three decades of standardised tests administered to American high-school students to see what had been happening to the country’s brightest sparks.
They draw two conclusions.
1) The Flynn effect (which weighs on the “nurture” side of the scales because it describes how IQ scores in general have been rising over the decades) applies in particular to the brightest of the bright.
2) The historic difference between the brainiest men and women has vanished. (Men now outnumber women only 4 to 1 instead of 13 to 1 for the top 0.01% of test scores
The three researchers drew their data from Duke University’s Talent Identification Programme, TIP, which is designed to ferret out especially clever candidates early on: all the participants had scored in the top 5% of ability when confronted with exams designed for much older students. TIP, in turn, draws on three national exams: SAT, EXPLORE and ACT. Altogether, Dr Wai, Dr Putallaz and Dr Makel looked at data from 1.7m children. Those data spanned the years between 1981 and 2010.
In the general population boys are well known to do a bit better than girls in maths. Girls, in turn, edge out boys on tests of verbal reasoning. The result is similar overall IQ scores.
By studying samples of intellectual outliers across 30 years, researchers can leverage right-tail data (i.e., samples at or above the 95th percentile on tests of ability) to uncover missing pieces to two psychological puzzles: whether there are sex differences in cognitive abilities among smart people, and whether test scores are rising (a phenomenon known as the Flynn effect) among smart people. For the first puzzle, data indicate that the high male-to-female ratio among extremely high scorers on measures of math ability has decreased dramatically, but is still likely one factor among many explaining female underrepresentation in some professions. For the second puzzle, data indicate that the right tail has risen at a similar rate as the general (or middle portion of the) distribution; it is thus likely that the entire curve is rising at a relatively constant rate, consistent with the Flynn effect, which may explain why a greater number of gifted students have been identified in recent years. However, the causes for these gains and whether they reflect real gains in intelligence continue to remain a mystery. We show how these two puzzles are linked and stress the importance of paying attention to the entire distribution when attempting to address some scientific questions.