15.2.1 Twin Studies

    Cards (70)

    • How is aggression defined in psychological terms?
      Intentional behavior to cause harm
    • Hostile aggression is driven by emotions like anger
    • Instrumental aggression aims to inflict harm impulsively
      False
    • What is an example of instrumental aggression?
      Tackling in football
    • The MAOA gene metabolizes neurotransmitters like serotonin and dopamine
    • Low activity of the MAOA gene is associated with higher aggression
    • What is the estimated heritability of aggression?
      30-50%
    • Match the gene with its function and effect on aggression:
      MAOA ↔️ Metabolizes serotonin and dopamine; Low activity leads to higher aggression
      COMT ↔️ Metabolizes catecholamines; Variants influence aggressive behavior
    • What type of twins share 100% of their DNA?
      Monozygotic
    • Concordance rates in twin studies measure the likelihood that both twins share a trait
    • Steps in estimating the heritability of aggression using twin studies:
      1️⃣ Compare MZ and DZ concordance rates
      2️⃣ Calculate the heritability using the formula
      3️⃣ Determine if genetics play a significant role
    • If MZ twins have higher concordance rates than DZ twins, genetics are likely significant in aggression
    • What is the estimated heritability of aggression in humans?
      30 - 50%\text{30 - 50\%}
    • The MAOA gene metabolizes serotonin and dopamine, and low activity is associated with higher aggression
    • What does the COMT gene metabolize?
      Catecholamines
    • Twin studies compare identical and fraternal twins to understand genetic and environmental influences on traits like aggression.
    • Monozygotic twins share 100% of their DNA.
    • What percentage of DNA do dizygotic twins share?
      50%
    • If MZ twins show higher concordance rates than DZ twins, genetics likely play a significant role in aggression.
    • The heritability of aggression in twin studies is estimated using a specific formula.
    • What do concordance rates in twin studies measure?
      Shared trait likelihood
    • Twin studies suggest that genetic factors are the only contributors to aggression.
      False
    • Heritability estimates from twin studies suggest that genetic factors account for 30-50% of the variation in aggression.
    • Which researchers conducted meta-analyses to confirm the heritability of aggression across cultures?
      Miles & Carey
    • Match the strength of twin studies with its explanation:
      Separating genetic and environmental influences ↔️ Estimates heritability by comparing MZ and DZ twins
      Natural experiments ↔️ Uses naturally occurring twin pairs
      High internal validity ↔️ Minimizes confounding variables
    • The shared environments assumption in twin studies assumes that twins share equally similar environments.
    • Researchers can estimate the heritability of traits by comparing MZ and DZ twins.
    • Twin studies are considered natural experiments because twins occur naturally without artificial manipulation.
    • Matched genetic similarity in twin studies minimizes confounding variables.
    • Twin studies assume that twins share equally similar environments, which may not always be true.
    • Twins may not be fully representative of the general population.
    • Aggression is commonly defined as behavior intended to cause harm or pain.
    • The psychological definition of aggression includes intentional physical or verbal behavior designed to cause harm.
    • Match the type of aggression with its description:
      Hostile Aggression ↔️ Driven by anger and aimed at harm
      Instrumental Aggression ↔️ Used to achieve a goal
    • Hostile aggression is often driven by emotions like anger.
    • Instrumental aggression uses harm as a means to an end rather than the end itself.
    • Key genes involved in aggression include MAOA and COMT.
    • The heritability of aggression is estimated to be around 30-50%.
    • Match the gene with its function and effect on aggression:
      MAOA ↔️ Metabolizes serotonin; low activity linked to higher aggression
      COMT ↔️ Metabolizes catecholamines; variants affect aggression
    • Twin studies compare MZ and DZ twins to understand genetic and environmental influences on aggression.