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Mostrando postagens com marcador Abagond. Mostrar todas as postagens
Mostrando postagens com marcador Abagond. Mostrar todas as postagens

sábado, 27 de agosto de 2011

Stephen Jay Gould on “The Bell Curve”

Stephen Jay Gould on “The Bell Curve”
Abagond, Sat 10 Jul 2010

Disclaimer: I have not read “The Bell Curve” for myself. The following is based instead on Stephen Jay Gould’s take on it. As a professor of biology at Harvard he knows the science way better than I do – like some of the important stuff “The Bell Curve” left out. He wrote about it in the 1996 edition of “The Mismeasure of Man”.

“The Bell Curve” (1994) by Richard J Herrnstein and Charles Murray is suppose to give the science proving that blacks in America have less intelligence in general than whites – and always will because intelligence, as measured by IQ, is mostly inborn or genetic. Further, they say this lack of intelligence is why things like crime, unemployment and illegitimacy are so high among blacks – and why throwing tax money at them will make little difference. In short: warmed-over social Darwinism.

As it turns out, even if you go by their numbers, IQ is weakly correlated with illegitimacy and so on – the numbers match up badly. So badly, in fact, that when they draw the lines on their graphs to show the relationships, they leave out the dots, the scatter of data points the lines are based on!

Further, correlation is not cause. After all, there is a much stronger correlation between your age and the national debt and yet neither causes the other.

And even Herrnstein and Murray admit that IQ is only 60% genetic. So only somewhat over half of these weak correlations-which-are-not-even-causes have anything to do with the inborn intelligence of black people.

And it gets worse:

All this is based on only one set of data with the numbers worked a certain way. But there are other sets of numbers, which they overlook – but would not if they had a strong case. And there are other ways to work the numbers. In fact, you can even show that it is impossible to measure intelligence by a single number!

That is no small point: Their argument depends on expressing intelligence as a single number. Not all scientists agree you can. The authors admit as much but do not make it plain why anyone would say that, a point which would cast their whole book into doubt – and make it clear that there are other ways to read the numbers. By leaving this out you do not see how weak their case is.

Their argument also depends on assuming that IQ is largely genetic therefore unchangeable. Not true.

Just because something is genetic does not mean it is set in stone. Height seems to be even more genetic than intelligence yet it is heavily affected by what you eat growing up – as people from India who bring up their children in America discover.

The same with IQ: in some countries it has gone up more in the past 50 years than the difference between blacks and whites in America. There is even a name for it: the Flynn Effect.

Thomas Sowell on “The Bell Curve” - Abagond

Thomas Sowell on “The Bell Curve”
Abagond, Fri 3 Dec 2010

Thomas Sowell, an economist, scholar and black right-wing thinker, says that Herrnstein and Murray’s “The Bell Curve” (1994) was an honest, fair-minded and well-written book, one that was far more level-headed than many who disagreed with it. It is certainly nowhere near as extreme as many made it seem. It has its faults, but it raises important questions and needs to be taken seriously.

The part that got everyone upset, of course, was the part on IQ and race, even though it is a small part of the book. Black thinkers and “leaders” (those are Sowell’s air quotes) made two mistakes in how they reacted to the book:

Straw man arguments: They painted the book’s position as being more extreme than it was. The book never says that the difference between black and white IQs is necessarily genetic or that genetics determines intelligence. It leans in that direction, certainly, but the science is not clear-cut enough to go that far.
Name-calling and mud-slinging: By reacting more with anger than with substance, they made it seem like the substance lay mainly with Herrnstein and Murray.
Blacks mainly argued that IQ tests are too cultural – they are written by middle-class whites, so they do not work well on blacks.

Sowell disagrees:

Blacks do best on the more cultural parts, the very parts that do in fact assume middle-class vocabulary and experience, and worse on the parts that do not, like those that test reasoning.
Any functioning IQ test should give blacks a lower score. Because blacks generally do worse at school than whites. The tests should catch this and they do. As it turns out, the tests work all too well.
A “culture-free” test would be useless because no one lives in a “culture-free” world. IQ tests, to work properly, have to be written by the mainstream culture.
But “The Bell Curve” has holes of its own:

Correlation is not cause. There are plenty of correlations between IQ and interesting things like future success in school, future income, divorce, infant mortality, crime, etc. But none of it proves cause. Nor are some of these correlations particularly strong.
The Flynn Effect: IQs have risen by 10 to 15 points in many countries in the space of 30 years. For some, like Jewish Americans, it has risen even faster. Genetics cannot account for this. The book brings up the issue, but avoids drawing the common sense conclusions.
Herrnstein and Murray fear that overall IQ will drop because low-IQ women tend to have more children. That makes sense but it is dead wrong: the Flynn Effect more than cancels it out.
There are way more black women with IQs over 120 than black men. That cannot be genetic either. Among whites there is no difference. The book does not even touch this one.
Sowell says the book should not be accepted unquestioningly, but then neither should it be dismissed out of hand.