16) Intelligence: Group Differences

What are some general points about sex differences in intelligence?

Spearman and Cattell claim there is no sex diffrences in general intelligence

Court (1983), Jensen (1998), Mackintosh (1998) find no significant differences b/w males/females

Irwing and Lynn (2005) - no differences up to age 15, adult men on average have higher IQ by 5pts than women - small effect size

What are sex differences in cognitive abilities?

Men show strong signs of superiority at spatial ability (spatial visualisation, mental rotation)

Woem show strong signs of being superior on tests of verbal abilities (spelling/speech), perceptual speed (rapidly identified matching items), and do better in school

What are some biological explanations of sex differences in intelligence?

Anatomical differences b/w male/female brains

Broca (1861) - male brain ave weight of 1325g, female brain ave weight of 1444g

Lateralisation differences - men predominantly use one heimsphere, women use both

Testosterone may explain spatial ability, but links are inconsistent

Evolutionary differences - men hunt/fight = better spatial skills

Men/women learning to be different in spatial abilities through practice

What are some environmental explanations of sex differences in intelligence?

Gender stereotypes and socialisation have been considered responsible

Stereotypes set up expectations that bring about self-fulfilling prophecies

Lee Jussim - expectations rooted in reality, self-fulfilling prophecies not particularly powerful

What does the racist book say about race differences in intelligence?

The Bell Curse (Hernstein and Murray, 1994) makes six assumptions

General intelligence factor, g, exists. IQ tests measure intelligence, IQ scores are stable, not biased towards different groups, and is substantially heritable (40-80%)

Claims that IQ is best predictor of college attendance, predicts job performance and low IQ predicts social problems

Reccomends stopping immigration and welfare, understand IQ cannot easily be raised, end affirmative action for failing students and invest in gifted students

What reasons are there to doubt a hereditarian thesis?

Many findings conserning IQ and achievement are consistent with IQ being highly heritable and genetically rooted if not racially.

However, here are some findings that are difficult to reconcile this point of view