R. Sternberg identified 4 questions associated with the "nature vs. nurture" question:

Level 1. Is personality due to inheritance or to environment?

Level 2: To what extent is personality a product of inheritance, to what extent is it a product of the environment, and to what extent is it a product of the interaction between the two?

Level 3: To what extent is personality a product of inheritance, to what extent is it a product of the environment, and to what extent is it due to the interaction between the two?

Level 4: To what extent is personality a product of inheritance biology, to what extent a product of the environment, and to what extent a product of the interaction between the two as a function of time and place?

What does each of these questions add to the others in the way of perspective on genetic vs. environmental influences on personality?

Are we born with a characteristic or are we born with a susceptibility to developing that characteristic?

Nonadditive effects are complex influences in which one gene is not expressed unless there are also certain others present.

If inheritance does not fully determine whether a person will have a given personality characteristic, what else might contribute, specifically?

Each of the following provides information on the heritability of personality. What are the strengths and weaknesses of each approach, in terms of its potential for advancing knowledge in this area? What kind of evidence, if any, do each offer in support of the hypothesis that personality is, in part, inherited?

1. True experiments (in which researchers manipulate independent variables to determine their effects on dependent variables)

2. Research on similarities between parents and children

            Assumptions of this approach?

            Support for genetic influences on personality?

Limitations?

3. Twin studies: comparisons between MZ & DZ twins who have been reared together.

        Assumptions of this approach?

        Support for genetic influences on personality?

        Limitations?

4. Research comparing adopted children’s personalities with those of the parents who reared them and with their biological parents.

        Assumptions of this approach?

        Support for genetic influences on personality?

Limitations?

5. Studying twins separated at birth & reared apart.

        Assumptions of this approach?

        Support for genetic influences on personality?

Limitations?

All of this together provides strong evidence for a inherited component of personality. (Why?).

They also likely overestimate the influence of genes on personality. Males may be expected to be more similar to other males than to females, all other things being equal, and females similarly may be more similar in personality to other females.

and found support or no support (?) for the hypothesis that extraversion/introversion is partly inherited.

In a study of twins reared apart from birth, investigators found greater similarity between monozygotic twins (relative to dizygotic twins), but less than compared with monozygotic twins reared together.

Can you describe the interaction effect revealed in Table 10.4?

Remember that when there is an interaction between two independent variables, one independent variable is intensifying, reducing, or even reversing the effect of the other independent variable on the dependent variable.

Which level (1-4) of the nature-nurture question would best be answered by the data in Table 10.4?

What seems to best distinguish extraverted individuals from introverted ones? Does one group simply enjoy people more, as common sense notions suggest?

Why would extraverts be happier individuals than introverts, on average, as the research seems to suggest?