intro to nature and nurture Flashcards
(28 cards)
What is temperament?
Innate, individual differences in emotion, activity level, and attention, present from infancy and stable across contexts.
What are Thomas and Chess’s (1977) three temperament categories?
Easy, Difficult, Slow-to-warm-up.
What are Rothbart et al.’s (2001) within-person temperament traits?
Fear, distress/anger, attention span, activity level, smiling/laughter.
What is the nature vs. nurture debate in the context of temperament?
It examines how much individual differences in temperament are due to genetic (nature) vs. environmental (nurture) factors.
Why can’t studies of biological families separate nature and nurture?
Because both genes and environment are shared between parents and children.
What does adoption design involve?
Comparing adopted children to their biological and adoptive parents to isolate genetic and environmental effects.
What similarities suggest genetic influences in adoption studies?
Similarity between adopted child and birth parents.
What similarities suggest environmental influences in adoption studies?
Similarity between adopted child and adoptive parents.
List 4 limitations of adoption studies.
Non-random placement in low-risk environments
Not generalisable to broader population
Do not account for prenatal influences
Adoption is an unusual event
What does twin design compare?
Similarity of traits in monozygotic (MZ) and dizygotic (DZ) twins to estimate genetic/environmental contributions.
What percentage of genes do MZ and DZ twins share?
MZ twins: 100%, DZ twins: 50%.
What does higher MZ similarity vs DZ suggest?
Genetic influence on the trait.
Give examples of temperament traits found to be heritable (Saudino, 2005).
Emotionality, activity, sociability, shyness, adaptability, attention/persistence, approach, distress, positive/negative affect.
What is the equal environments assumption?
The assumption that MZ and DZ twins share equally similar environments.
Why is the equal environments assumption problematic?
MZ twins often share more similar environments (womb + postnatal) than DZ twins.
Why might MZ twins not be genetically identical?
Post-conception mutations and biological mechanisms can cause genetic variation between them.
Why might twin studies not generalise to the population?
Twins have increased prenatal risks and developmental differences.
What is heritability?
The proportion of variance in a trait within a population that is due to genetic differences.
Does heritability apply to individuals?
No—it applies only to populations.
Can heritability change?
Yes—it varies by population, environment, and time
What does heritability not tell us?
It doesn’t identify specific genes or capture gene-environment interactions.
What was the sample in Lemery-Chalfant et al. (2013)?
807 twin pairs (301 MZ, 263 same-sex DZ, 243 opposite-sex DZ), age ~9.
What were the key findings on temperament heritability?
Effortful control: 54% heritable
Negative affectivity: 79%
Extraversion: 49%
What environmental finding did Lemery-Chalfant et al. (2013) report?
Home environments (chaotic/unsafe) are heritable and influence extraversion.
