Biological Perspective

1
Biological Perspective

• The Scientific Study of Behavior

2
Biological Correlates of Behavior

• Examples of how what happens in the body can have
  a dramatic effect on behavior include
• Damage to various areas of the brain
• Effect of drugs on brain and behavior
• Genetic contributions to explanations of behavior
• Effects of hormonal change on behavior

3
Brain Damage

• Damage to occipital lobe may result in cortical
  blindness or visual anosognosia (denial of
  blindness)
• Parietal Lobe damage can result in disorders of
  perception such as
• Apraxia inability to identify objects
• Hemisomatognosia unawareness of the opposite
  side of the body to the damage
• Phantom limb sensations still present from an
  amputated limb

4
Brain Damage

• Damage to the Temporal Lobe such as Wernickes
  Aphasia
• People with this disorder loss their ability to
  understand language
• They may be able to speak clearly, but the words
  make no sense word salad
• However, people with Wenickes aphasia are able
  to comprehend non-verbal sounds and respond
  appropriately

5
Effect of Drugs on Brain and Behavior

• A Drug is any chemical not required for the
  maintenance of health that alters biological
  function or structure when taken
• Positive effects of drugs
• Pain relief
• Maintenance of bodily functions
• Protective effects
• Negative effects of drugs
• Drug abuse and dependency
• Drunk driving and other self-destructive
  behaviors

6
Blood-Brain Barrier

• Prevents most toxins from the blood stream
  entering the brain because the pores in the
  capillary walls of the CNS are relatively small
  and restrict movement of foreign molecules into
  the brain via the blood
• Brain chemistry is a matter of balance and using
  drugs generally disrupts this balance ( Mouse
  Party)
• Allows the following substances to pass into the
  brain
• water oxygen carbon dioxide
• small lipid (fat) soluble substances
• small electrolytes

7
Genetic Explanations of Behavior

• Genetic research is a controversial area that has
  ethical, legal, social and practical implications
• The heritability of psychological characteristics
  has remained an influential idea within psychology

8
Sir Francis Galton (1822-1911)

• Coined the phrase nature versus nurture
• Developed statistical concepts of correlation and
  regression to the mean
• Conducted twin studies of the differences between
  monozygotic and dizygotic twins

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Sir Francis Galton

• Argued that intelligence had a genetic basis and
  that genius was something that could be traced
  across generations
• Was influenced by his cousins (Charles Darwin)
  theories of evolution
• He was convinced that success was due to superior
  qualities passed down to offspring through
  heredity - link to determinism
• He proposed ideals of eugenics in which he
  advocated human breeding restrictions to curtail
  the breeding of feeble-minded individuals

10
Sir Cyril Burt (1883-1971)

• Suggested as much as 80 of individual
  differences in intelligence were related to
  inherited or genetic factors
• In his Twin studies, he showed the IQs of
  identical twins reared apart much closer than the
  IQs of non-identical twins
• Concluded that genetic factors were more
  important than environmental factors in
  determining intelligence

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Hans Eysenck

• Developed the British Twin Register early in his
  career
• His studies indicated that genes contribute
  significantly to measures of extraversion,
  neuroticism, psychoticism, personal adjustment
  and social attitudes
• He estimated the heritability of criminality at
  60

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Genetic Research

• Has improved our understanding of intellectual
  disability
• Fragile-X Syndrome leads to the breakdown of
  the X chromosome and explains why more boys than
  girls have intellectual disabilities
• Color blindness and hemophilia are also more
  common in males and are related to the X
  chromosome

13
Genetic Research

• Other disorders such as
• Alzheimers disease
• Huntingtons chorea
• Schizophrenia
• Are also thought to have a strong genetic
  component
• Behavioral geneticists are interested in how
  genetics can be used to understand individual
  differences between people.

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Twin Studies

• Identical (Monozygotic ) Twins share 100 of
  their DNA
• Non-Identical (Dizygotic) Twins share only 50 of
  their DNA
• Comparisons between these two groups provide a
  useful basis for understanding the role that
  genes play in shaping behavior