The Bell Curve

Evaluation & Critique

Where Does It Go Wrong?

• Claim that intelligence is fixed & stable

• Claim that ethnic differences are genetic

• Technical issues:

AFQT not good IQ test

regression analysis, w/out goodness of fit

• Definition of intelligence as g

• Sleight of hand in moral argument

Evidence Intelligence not Fixed

“ Flynn Effect ”

Raven’s Matrices

Flynn Effect

Flynn Effect

Ethnicity and Race• Within group vs. between group

variation

• Social Inequality & Test Scores

• Genes vs. Environment: recent twin & adoption studies

• Social Inequality & Stress

• “Stereotype Threat”

Genetic Variability &Between-Group Differences

Iowa soil Nevada soil

Inequality & IQ / Achievement Scores

Country High Scores Low Scores

U.S. Whites

Whites

Blacks

Latinos

Great Britain English Irish, Scottish

Northern Ireland

Protestants Catholics

Australia Whites Aborigines

New Zealand Whites Maoris

Inequality & IQ / Achievement Scores

Country High Scores Low Scores

South Africa English Afrikaaners

Belgium French Flemish

Israel Jews

Western Jews

Arabs

Eastern Jews

India High caste Low caste

Czech Slovaks Gypsies

Japan Non-Burakumin Burakumin

Turkheimer 2003 Twin Studies

Environmental influence greater for children in poor families:

• Genes set upper limit

• Environment determines whether limit reached

“If you have a chaotic environment, kids’ genetic potential doesn’t have a chance to be expressed.”

Capron & DuymeFrench Adoption Study 1

• High-SES high-SES: IQ = 120

• High-SES low-SES: IQ = 108

• Low-SES low-SES: IQ = 92

• Low-SES high-SES: IQ = 104

Capron & DuymeFrench Adoption Study 2

Sample of abused / neglected infants, adopted between age 4 and 6

• IQ at adoption = 77

• IQ 9 years later– Farmers & laborers: 86– Middle class: 92– Upper class: 98

Enrichment Effects

Social Inequality & Stress

• Height: U.S. men: 5’ 9” Dutch men: 6’ 1”

• Subordinate primates:glucocorticoid-cascade hypothesis“allostatic load” hypercortisolemiadepression & social isolationatrophy of hippocampal neuronspoor ovarian functioncompromised immune functioning “stunted growth” & “accelerated

aging”

Stereotype ThreatClaude Steele

• Whites & blacks take GRE-like test• ½ told “measures intelligence” ½ told

developing test of problem-solving

• White scores same in both conditions

• Black scores equal to whites in “developing test” condition

• Black scores lower in “measures intelligence” condition

Stereotype Threat

• Women score lower when test measures “math ability”

• Asian women taking math test:

femaleness primed score lower

Asianness primed score higher

Stereotype Threat• Golf study:

-- Blacks out-play whites in “test of athletic ability”

-- Blacks out-played by whites in “test of athletic intelligence”

• Basketball vertical leap study:

-- Whites can’t jump when experimenter is Black !!!

Ethnicity and Race• Within group vs. between group

variation

• Social Inequality & Test Scores

• Genes vs. Environment: recent twin & adoption studies

• Social Inequality & Stress

• “Stereotype Threat”

What Harm Does It Do?

• Racist view of ethnic differences

• Downplays influence of social environments

• Narrow theory of intelligence – fixed & unchangeable

• “Social Darwinism” not socio-biology

• Moral “sleight of hand”

Moral “Sleight of hand”

Two sets of ideas, joined from Galton to Murray & Herrnstein:

1. IQ should be measured as purely abstract operations performed on tasks uncontaminated by Real World

2. IQ scores can be viewed as the source of virtue, morality, ambition, & drive.

The Bell Curve (p. 21) :

“This identification of IQ with attractive human qualities in general is unfortunate and wrong.”

“This thing we know as IQ is important but not a synonym for human excellence.”

Herrnstein (1971) :

“It is only when able and energetic individuals can rise and displace the dull and sluggish ones that there can be sorting out of people according to inherited differences.”

The Bell Curve:

“The difference between people of low cognitive ability and the rest of society may be put in terms of a metaphor: Everyone has a moral compass, but some of those compasses are more susceptible to magnetic storms than others.” (p. 543)

What Good Does It Do?• Danger of accelerating stratification of American

society

• Sorting process in America’s schools

• High-tech society may not have a place for everyone

• Challenges naïve liberal view that all differences environmental

• Challenges view that wealth & status are rewards for hard work; poverty just punishment for laziness

Raise Key Moral Question:

“If it’s not someone’s fault that he is less intelligent than others, why should he be penalized in his income and social status?”

(p. 527)

Tension Animating Bell Curve

• They approve of IQ-based sorting & stratification

• But: this process destroying the social values they cherish & undermining democracy

Question Basic Values

• Thrasymachus (Plato): “justice” is the ideology of strong?

• H & M: “Meritocracy” is the ideology of the cognitive elite?

A Place for Everyone “At the heart of our thought is the quest for human dignity. The central measure of success for this government, as for any other, is to permit people to live lives of dignity…” ( p. 551)

“The broadest goal is a society in which people… can find, and feel they have found, a valued place for themselves.”

(p. 535 )

Thomas Hobbes“The value or worth of a man is, as

of all other things, his price – that is to say, so much as would be given for the use of his power… And as in other things so in men, not the seller but the buyer determines the price….

“To value a man at a high rate is to honor him, at a low rate is to dishonor him.”

-- Leviathan, 1651

A Valued Place

A low-IQ underclass, with no valued place, is a creation of modern society

Charles Darwin

“If the misery of our poor be caused not by the laws of nature, but by our institutions, great is our sin.”

Voyage of the Beagle