However, considering the SPM alone over its entire age range, there was a net slowing down of the Flynn effect (0.15 points per year for 1979-2008 vs. 0.23 points per year for 1938-1979), because at the highest ages tested the Flynn effect went into reverse (a 1.9 point IQ drop from 1979 to 2008 for 14- & 15-year-olds). Presumably it’s this data that suggested a reversal of the UK Flynn effect to you, and your inference differed from Flynn’s because the two of you looked at different slices of the data. Flynn focused on younger children, who have rising IQs, and you remembered the data from older children, who have falling IQs. (It’s a shame there are no recent adult data to resolve which trend the grown-ups are following.)
Hm, maybe I’m missing something on how the tests interact, but if the older range up to 2008 on the SPM was falling, doesn’t that tell you how the adults are going to turn out simply because they are closer to being adults than the younger counterparts?
Hm, maybe I’m missing something on how the tests interact, but if the older range up to 2008 on the SPM was falling, doesn’t that tell you how the adults are going to turn out simply because they are closer to being adults than the younger counterparts?
A priori, it does seem like the older kid trend should be more relevant to adults than the younger kid trend.
However, British IQ gains might have a V-shaped relationship with age: solid gains in younger kids, lesser gains (or indeed losses) in teenagers, and a return to higher gains in adulthood. As written that probably sounds like a wilful disregard of Occam’s razor, but there is some precedent.
I went back to Flynn’s original 1987 article “Massive IQ Gains in 14 Nations” and looked up Great Britain. The only Matrices results seem to be for the SPM, but as well as the familiar 1938-1979 results, there’s an adult IQ gain estimate. Flynn got it by comparing a 1940 sample of militiamen (average age 22) at a WW2 training depot to the 15½-year-olds in the 1979 sample, adjusting the gain estimate to partially offset the teenagers’ age disadvantage.
Comparing the adult(ish) gains to the child gains reveals something like a V-shaped trend: ages 8-11 gained 0.25 points/year, ages 12-14 gained 0.11 points/year, and the 15½-year-olds outpaced the militiamen by 0.18 points/year. In this case, the older kids’ gain rate was no better as an estimate of the (pseudo-)adult rate than the younger kids’ rate.
Hm, maybe I’m missing something on how the tests interact, but if the older range up to 2008 on the SPM was falling, doesn’t that tell you how the adults are going to turn out simply because they are closer to being adults than the younger counterparts?
(Guess I’ll have to read his book eventually.)
A priori, it does seem like the older kid trend should be more relevant to adults than the younger kid trend.
However, British IQ gains might have a V-shaped relationship with age: solid gains in younger kids, lesser gains (or indeed losses) in teenagers, and a return to higher gains in adulthood. As written that probably sounds like a wilful disregard of Occam’s razor, but there is some precedent.
I went back to Flynn’s original 1987 article “Massive IQ Gains in 14 Nations” and looked up Great Britain. The only Matrices results seem to be for the SPM, but as well as the familiar 1938-1979 results, there’s an adult IQ gain estimate. Flynn got it by comparing a 1940 sample of militiamen (average age 22) at a WW2 training depot to the 15½-year-olds in the 1979 sample, adjusting the gain estimate to partially offset the teenagers’ age disadvantage.
Comparing the adult(ish) gains to the child gains reveals something like a V-shaped trend: ages 8-11 gained 0.25 points/year, ages 12-14 gained 0.11 points/year, and the 15½-year-olds outpaced the militiamen by 0.18 points/year. In this case, the older kids’ gain rate was no better as an estimate of the (pseudo-)adult rate than the younger kids’ rate.