INTELLIGENCE2.2 Genetics and behaviourDiscuss the extent to which

genetics influence behaviour

IQ

What is intelligence quotient (IQ)?

Should indicate one’s genetically endowed intellectual potential

IQ

The abbreviation "IQ" comes from the German term Intelligenz-Quotient, originally coined by psychologist William Stern.

When modern IQ tests are devised, the mean (average) score within an age group is set to 100 and the standard deviation (SD) almost always to 15.

Thus, the intention is that approximately 95% of the population scores within two SDs of the mean, i.e. has an IQ between 70 and 130.

IQ scores are used as predictors of educational achievement, special needs, job performance and income.

What about crime? Read p. 61-63 if you want to find out and there is an article online Seeking the criminal element

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”?

http://www.mensa.se/provtesthttp://www.mensa.org/

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?

Is there any difference between men and women?

Research on IntelligenceFamily and Twin studies

Bouchard and McGue (1981) reviewed 111 studies from around the world of IQ correlations between siblings

A meta-analysisResults: the closer the kinship, the

higher the correlation for IQ

This supports the idea that IQ mostly derives from our genes.

More research The Minnesota Twin Study by Bouchard

et al 1990 Longitudinal study since 1979 & cross-

cultural study. Use media to recruit participants.

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

Evaluation?

Critique

Media coverage to recruit participants (self-selected sample)

Ethical concerns – reunited the twins No adequate control to establish the

frequency of contacts between the twins prior to the study

“equal environment assumption” – are all twins treated the same way (even MZ twins?)

No cause and effect

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) in France 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 have studied?

Evaluation of research about IQ

Think critacally – using the following:

1. Method?2. Ethics?3. Gender?4. Culture?

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?Finish as homework (including reading the handout “the development of IQ test performance” and summarize the “two sides” with 2-3 arguments on each side – to be handed in