The Complex Relationship Between Genetics, Intelligence, and Behavior: Insights and Debates

1. Intelligence 2.2 Genetics and behaviour

3. IQ • What is intelligence quotient (IQ)? • Should indicate one’s genetically endowed intellectual potential

4. Do be a thinker on p. 54 • Answer questions in groups of 4: • Do you think that these tests appropriately evaluate your intelligence? • Do you feel that the tests were adequate? Why or why not? • How would you change the tests to make them reflect more accurately what you consider to be your “intelligence”?

5. 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

6. 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 crimethan 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.

7. 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?

8. Research on Intelligence • Bouchard and McGue (1981) reviewed 111 studies of IQ correlations between siblings A meta-analysis Results: the closer the kinship, the higher the correlation for IQ

9. 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

10. 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

11. 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”

12. 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?

13. 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?

14. Stereotype threat affects cognitive ability Women and Math stereotype threat: • http://www.youtube.com/watch?v=tjn6ZSU_zS0&feature=related Stereotype threat: http://www.youtube.com/watch?v=nGEUVM6QuMg

15. Concluding thoughts on intelligence • Found out (p.56) and answer in writing: • What is eugenics? • What is the Less effort hypothesis? • Does IQ change over time? • Which factor is the most important environmental factor in development of IQ? • Why has the average mean on IQ tests been going up over the years?