Topic 1.1 - Interaction of Heredity and Environment

Nature vs. Nurture

Heredity and genetic influences = Nature

Environmental factors = Nurture

Nature + Nurture:

The (nature) genes you are born with are the foundations, the (nurture) environment you grow up in is what makes you a unique person.

• Epigenetics and gene expression:

  • Just because you carry the gene doesn’t mean it needs to be expressed

  • Twin studies

    • Identical twins (monozygotic)

      • Same genes, same environment

    • Fraternal twins (dizygotic)

      • Different genes, same environment

  • Family studies

    • compares the child to the entire extended family, looking for genes in common.

    • you cannot separate nature from nurture

  • Adoptive studies

    • a child’s traits are compared to the adoptive and biological family

    • completely separates nature from nurture

    • adoptive family share nurture

    • biological family share nature

Evolutionary Psychology:

• believed that all behaviors are learned through evolution and are formed to help adapt and survive

  • x: a fear of snakes helped ancestors survive venomous snakes that could kill.

    • fear gets passed on to the descendants.

• Examples:

  • Altruism: tribes that worked and helped each other survived longer then those who didn’t.

  • Mate Selection:

    • Women tend to look for protection, stability, and long-term support

    • Men tend to look for youth, health, and traits liked to fertility.

  • Externalizing Disorders: mental disorders characterized by externalizing behavior

    • more common in men

    • ADHD is an example of externalizing disorders. And its more common in males than it is in females.

    • Disorders linked with aggression are more common in men because of their ancestry.

• Eugenics: Picking out specific genes to reproduce

  • only people with “good genes“ could reproduce

  • people with “bad genes“ were force sterilized.