Nature � Nurture by n3NYd0M



                             Nature – Nurture

      Nature – genetics or biology
      Nurture – environmental influences

Babies differ from one another not only in physical appearance but also in

What contributes to these individual differences at such a young age?

Before birth – transactions among a vast array of hereditary and
environmental factors begin. Such transactions between genes and the
environment make each newborn unique, and they continue to shape the
individual’s characteristics throughout his/her life span.

What is more important? Nature or nurture?

Researchers who are biologically oriented = nature view.
Researchers who are more environmentally oriented = nurture view. They
emphasize the role of learning.

How the environment influences the expression of genes: The concept of
range of reaction helps explain how environments influence genes.

Some examples of the interplay between nature & nurture:
   Intelligence
   Psychiatric disorders = diathesis stress model
   Temperament: a. slow-to-warm-up child: low in activity level &
     tends to respond negatively to new stimuli at first but to adapt slowly
     to new objects or novel experiences after repeated contacted with
     them. B. difficult – 10%of all babies sleep & eat irregularly, become
     easily upset by new situations, and experience extremes of fussiness
     and crying. c. easy – 40% are friendly, happy, & adaptable.

Can we change the outcome of someone’s intelligence? What about if
someone has a psychiatric disorder like autism?

Methods for studying individual differences
   Adoption & twin studies
   Monozygotic versus Dizygotic twins
   Shared & nonshared environment

Prenatal Development

      Cephalocaudal development: head to tail.
      Proximal-distal development: toward the center & away from the


      A teratogen exerts its effects largely during critical periods.
      Each teratogen exerts certain specific effects.
      Either maternal or fetal genotypes can affect the developing
       organism’s response to teratogenic agents and may play an important
       role in determining whether offspring will display abnormalities.
      The effects of one teratogen may intensify the effects of another.
      A particular teratogen may affect the fetus but have no discernible
       effect on the mother.
      A particular teratogen may produce a variety of deviations,
      The longer a fetus is exposed to a particular teratogen and the
       greater the intensity of the teratogen’s effects, the more likely it is
       that the fetus will be seriously harmed.

Environmental Dangers
    Legal & Illegal Drugs:
      Smoking & drinking alcohol
      Women who are chronic smokers
      Passive smoke
      Men who smoke
      Alcohol: Fetal alcohol syndrome
      Heroine, morphine, methadone

   Other Factors:
   Emotional state
   Genital herpes

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