EDST 391 Intelligence in Everyday Life


P/F Writing Assignment for Day 18

Genetics of intelligence I: Heritability


  • Bouchard  (“Never the twain shall meet”)
  • Plomin & Petrill, pp. 53-59 
  • Deary's Intelligence, pp. 85-88 (Dataset 9). Pages 67-81 are recommended if you are not confident from the other readings about how heritability is estimated and what the key results are.
  • Sample data on heritability of attitudes and life events --bring it to class. Try to figure out these data, or your questions about them, before you get to class.
  • Dateline video on twins (in class)

Our readings for today come from the field of behavioral genetics, which is the study of the (partly) genetic basis of many differences among us in personality, ability, and the like. They are designed to introduce you to the concept of heritability, the range of traits that are heritable to some degree, and the ways in which scientists go about estimating heritability. Not surprisingly, the research relies heavily on "experiments of nature"--identical twins and adopted children.

1. What is the logic behind looking at the similarities among different sorts of family members (especially twins and adoptees) in order to estimate the heritability (and environmentality) of IQ? It might help to refer to Plomin's Figure 2 (p. 57).

2. Turning to Deary's Dataset 9, what was the:

  1. guiding question
  2. kinds of people studied and data collected
  3. major conclusion

3. What in the set of readings puzzled, confused, or simply surprised you? Please explain. (List at least two or three things.)