Whites, N =19,726
Blacks, N = 3,441As a follow-up to the last post, let's look at IQ trends by race since the GSS vocabulary test was first given in 1974 (WORDSUM). The test is 10 questions. The overall mean for whites is 6.3. Over the 35-year span, the percentage of whites with below-average scores has dropped about 5 points, and the top two categories have shrunk about the same. The average-to-above-average has picked up the slack.
For blacks (bottom graph), the overall mean is 4.9. The share scoring 4 or fewer has dropped over the period from around 45% to 30%. The improvement began in the late 80s. The percent scoring 5 or 6 grew from 38% to 58%. That's the good news. The bad news is that those scoring 7 or higher appears to have shrunk. (It's not easy to tell since few blacks score so high, so there is a lot of year-to-year fluctuation).
So, the main story seems to be that both blacks and whites have expanded their middles at the expense of their extremes. Next, let's look at mean changes by year:
Mean IQ (standard deviation in parentheses)
Whites
1970s 6.2 (2.2)
1980s 6.1 (2.2)
1990s 6.3 (2.0)
2000s 6.4 (2.0)
Blacks
1970s 4.6 (1.9)
1980s 4.7 (2.1)
1990s 5.0 (1.9)
2000s 5.2 (1.9)
The past three or four decades have been good for blacks. Their mean has increased more than whites, and so the IQ gap has narrowed from 1.6 in the 70s to 1.2 in this decade. Another way to look at it is the gap in standard deviation units (SD). The gap fell from .72 SD in the 70s to .60 SD now. The narrowing is significant, but the gap is still large.
It's also important that, while the white mean has gone up a bit since the 70s, the standard deviation is now smaller. This is due to fewer whites having low scores, but it is also due to a smaller share of smart people.
It looks like America's efforts may have raised the scores of the bottom half, while ignoring the high end. As La Griffe has shown, a nation's wealth depends on the fraction of the population that is intelligent. So it makes little sense to obsess about the bottom, but that seems to be what we're doing. (I'm not sure what has brought up low scores. Getting rid of really bad schools still around in the 60s? Nutrition? All that TV watching improving vocabulary?).
1970s 6.2 (2.2)
1980s 6.1 (2.2)
1990s 6.3 (2.0)
2000s 6.4 (2.0)
Blacks
1970s 4.6 (1.9)
1980s 4.7 (2.1)
1990s 5.0 (1.9)
2000s 5.2 (1.9)
The past three or four decades have been good for blacks. Their mean has increased more than whites, and so the IQ gap has narrowed from 1.6 in the 70s to 1.2 in this decade. Another way to look at it is the gap in standard deviation units (SD). The gap fell from .72 SD in the 70s to .60 SD now. The narrowing is significant, but the gap is still large.
It's also important that, while the white mean has gone up a bit since the 70s, the standard deviation is now smaller. This is due to fewer whites having low scores, but it is also due to a smaller share of smart people.
It looks like America's efforts may have raised the scores of the bottom half, while ignoring the high end. As La Griffe has shown, a nation's wealth depends on the fraction of the population that is intelligent. So it makes little sense to obsess about the bottom, but that seems to be what we're doing. (I'm not sure what has brought up low scores. Getting rid of really bad schools still around in the 60s? Nutrition? All that TV watching improving vocabulary?).
Is it possible to check how the narrowing for the black-white gap in WORDSUM scores measures against the narrowing for the black-white gap in SAT, GRE, and traditional IQ scores?
ReplyDeleteI'm interesting to see if the narrowing is similar.
Thats interesting. If anything, the literature out there explains that the gap has gotten even wider in recent years because of lack of control at the bottom(70 IQ women).
ReplyDeleteSAT scores show the same wide and not narrowing gap since the 90s.
http://aera.net/uploadedFiles/Journals_and_Publications/Journals/Educational_Researcher/3101/3101_Lee.pdf
P. Rushton in the G factor put it at 1.2SDs based on Ravens Matrices taken in the 80s so halving it is unlikely.
However this shouldn't hold back NAMs or Arabs. There was an interesting article in the New Yorker about "neuroenhancers" aside from Ritalin to be out by 2012. This is probably the best bet.
"As La Griffe has shown, a nation's wealth depends on the fraction of the population that is intelligent."
ReplyDeleteI wouldn't say he's shown it: he's argued for it, but a thesis that sweeping can't be established on the basis of a couple of essays.
He's done sophisticated data analyses, not essays. That's a tad more persuasive than empty skepticism.
ReplyDelete