INTELLIGENCE2.2 Genetics and behaviour

IQ

What is intelligence quotient (IQ)? Should indicate one’s genetically

endowed intellectual potential

Do be a thinker on p. 54

Answer questions in groups of 4:1. Do you think that these tests

appropriately evaluate your intelligence?2. Do you feel that the tests were adequate?

Why or why not?3. How would you change the tests to make

them reflect more accurately what you consider to be your “intelligence”?

Intelligent Research

Alfred Binet a pioneer in intelligence research, beginning of the 20th century

Pr. Richard J. Herrnstein & Charles Murray 1994, Harvard: The Bell Curve

The Bell Curve

- The Bell Curve is a best-selling but controversial 1994 book. Its central argument is that intelligence is a better predictor of many personal dynamics, including financial income, job performance, chance of unwanted pregnancy, and involvement in crime than are an individual's parental socioeconomic status, or education level. The book also argues that those with high intelligence, the "cognitive elite", are becoming separated from those of average and below-average intelligence, and that this is a dangerous social trend.

Intelligence – ongoing debate

What is it? How can it be measured? Charles Spearman – theorized that there

is a general intelligence factor, which he called the “g” factor.

Modern intelligence testing attempts to assess this “g”

But the question is: where does “g” come from?

Research on Intelligence

Bouchard and McGue (1981) reviewed 111 studies of IQ correlations between siblings

A meta-analysisResults: the closer the kinship, the higher

the correlation for IQ

More research

The Minnesota Twin Study by Bouchard et al 1990

Longitudinal study since 1979 & cross-cultural study

MZA (identical twins raised apart) compared to MZT (identical twins raised together)

The mean age was 41 years (start of the study), differ from most other research which is carried out on adolescents

Each twin completed 50 hours of testing and interviews

results

The concordance rates of intelligence can be found in a table on p. 55

The study concluded that 70% of intelligence can be attributed to genetic inheritance – leaves 30% to other factors

Critique

Media coverage to recruit participants Ethical concerns – reunited the twins No adequate control to establish the

frequency of contacts between the twins prior to the study

“equal environment assumption”

Adoption studies

Scarr and Weinberg (1977) and Horn et al (1979) studied parents who raised both adopted and natural children

So same environment – any differences should be due to… what?

Results

Found no significant difference in IQ correlations! Very interesting findings

Another study by Wahlstein (1997) found that transferring children from low socio-economic status family to one where they are high socio-economic status improved childhood IQ scored by 12-16 points (about one SD)

Shows that an enriched environment may raise IQ in children.

Does this resemble to something else we studied?

Stereotype threat affects cognitive ability

Women and Math stereotype threat: http://www.youtube.com/watch?v=tjn6ZS

U_zS0&feature=related

Stereotype threat:http://www.youtube.com/watch?v=nGEUVM6QuMg

Concluding thoughts on intelligence

Found out (p.56) and answer in writing:1. What is eugenics?2. What is the Less effort hypothesis?3. Does IQ change over time?4. Which factor is the most important

environmental factor in development of IQ?

5. Why has the average mean on IQ tests been going up over the years?