Biological Psychology

1
Chapter OneThe Major Issues
2
Biological Psychology

• study of the physiological, evolutionary, and
  developmental mechanisms of behavior and
  experience

3
The Major Issues

• The Mind-Brain Relationship
• Biological Explanations of Behavior
• Four categories
• physiological-relates a behavior to the activity
  of the brain and other organs
• ontogenetic-describes the development of the
  structure or behavior
• evolutionary-examines a structure or a behavior
  in terms of evolutionary history
• functional-describes why a structure or behavior
  evolved as it did

4
The Major Issues

• The Mind-Brain Relationship
• The Brain and Conscious Experience
• Dualism
• defined-the belief that mind and body are
  different kinds of substances, that exist
  independently but somehow interact
• DesCartes-proposed that mind and brain interact
  in the pineal gland

5
The Major Issues

• The Mind-Brain Relationship
• The Brain and Conscious Experience
• Monism
• defined-the belief that the universe consists of
  only one kind of existence
• Forms of Monism
• materialism-the view that everything that exists
• is material or physical
• mentalism-the view that only the mind really
  exists
• identity position-the view that mental processes
  are the same thing as certain kinds of brain
  processes, but described in different terms

6
The Major Issues

• The Mind-Brain Relationship
• Discussions of Consciousness
• David Chalmers-proposed distinguishing easy
  problems from hard problems
• easy problems
• pertain to many phenomena to which we apply the
  term consciousness
• Ex the difference between wakefulness and sleep,
  and the mechanisms that enable us to focus our
  attention
• hard problem-the question of why and how any kind
  of brain activity is associated with consciousness

7
Nature or Nurture

• The Genetics of Behavior
• Chromosome Structure
• genes-units of heredity that maintain their
  structural identity from one generation to
  another
• chromosomes-strands of genes
• deoxyribonucleic acid-DNA-when it exists as a
  double strand in a helix, it makes up a
  chromosome when it exists in a single strand, it
  serves as a template for the synthesis of RNA
• ribonucleic acid (RNA)-single strand chemical
  that can serve as a template for the synthesis of
  proteins
• enzymes-biological catalysts that regulate
  chemical reactions in the body

8
Figure 1.6  How DNA controls development of the
organism The sequence of bases along a strand of
DNA determines the order of bases along a strand
of RNA RNA in turn controls the sequence of
amino acids in a protein molecule.
9
Nature or Nurture

• Mendelian Genetics Contd
• Patterns of Inheritance
• homozygous-having an identical pair of genes on
  two chromosomes
• heterozygous-having an unmatched pair of genes on
  two chromosomes
• dominant gene-expressed in either the homozygous
  or heterozygous condition (ex Bb or BB will be
  expressed as brown eyes)
• recessive gene-only expressed in the homozygous
  condition (ex bb is the only condition where
  blue eyes will be expressed)

10
Figure 1.7  Four equally likely outcomes of a
mating between parents who are heterozygous for a
given gene (Tt) A child in this family has a 25
chance of being homozygous for the dominant gene
(TT), a 25 chance of being homozygous for the
recessive gene (tt), and a 50 chance of being
heterozygous (Tt).
11
Nature and Nurture

• Mendelian Genetics Contd
• Patterns of Inheritance
• Linkage and Crossing Over
• Occurs when the inheritance of one gene is linked
  to inheritance of another gene
• Occurs when a pair of chromosomes break apart and
  reconnect exchanging parts of each chromosome
• Sex-Linked Genes
• genes that are located on the sex chromosomes
• an X-linked recessive gene will always be
  expressed in a male while a female will only
  express the gene if both of her X chromosomes
  carry the recessive gene

12
Nature and Nurture

• Mendelian Genetics Contd
• Patterns of Inheritance
• Sex-Limited Genes
• present in both sexes but is expressed in only
  one sex,
• or has a much stronger effect in one sex than
  the other
• the genes do not need to be on the sex
  chromosomes
• these genes are expressed only after activation
  by sex hormones
• Sources of Variation
• Recombination-some genes from one parent and some
  
• from the other, that combine to yield
  characteristics
• not found in either parent
• Mutation-a random change in a single gene

13
Nature and Nurture

• Heritability
• defined-an estimate of how much of the variance
  in some characteristic within a population is due
  to heredity
• Ranges from 0 to 1
• If 0 then hereditary differences account for none
  of the observed variations in that characteristic
• If 1 then hereditary differences account for all
  of the observed variations in that characteristic

14
Nature and Nurture Contd

• How Heritability is Determined
• Compare similarities in monozygotic twins versus
  dizygotic twins
• Compare adopted children and their biological and
  adoptive parents
• Can heritability be modified?
• PKU prevention as an example

15
Figure 1.8  Prenatal development of monozygotic
and dizygotic twins In most cases, monozygotic
(identical) twins develop in a single placenta
and have the same blood supply. Dizygotic
(fraternal) twins develop in separate placentas.
Therefore, monozygotic twins have more similar
prenatal environments as well as more similar
heredities.
16
The Evolution of Behavior

• Evolution
• Defined-change over generations in the
  frequencies of various genes in a population
• How it occurs-Characteristics that lend
  themselves to survival assist an individual in
  surviving to reproductive age, therefore these
  survival genes are passed on to the next
  generation
• Artificial Selection
• Choosing individuals with a desired trait and
  making them the parents of the next generation

Video
17
Common Misunderstandings About Evolution

• Does the use or disuse of some structure or
  behavior cause an evolutionary increase or
  decrease in that feature?
• Have humans stopped evolving?
• Does evolution mean improvement?
• Does evolution act to benefit the individual or
  the species?

18
Sociobiology

• Defined-studies the issues that concern the
  evolution of social behavior
• It emphasizes functional explanations
• Criticisms of the field
• Functional explanations are often speculative
• Sociobiological explanations sometimes imply that
  human behavior has evolved to be as it is, and
  therefore it should stay that

19
Use of Animals in Research

• Reasons for Animal Research
• The underlying mechanisms of behavior are similar
  across species and sometimes are easier to study
  in a nonhuman species
• We are interested in animals for their own sake
• What we learn about animals sheds light on human
  evolution
• Certain experiments cannot use human subjects
  because of legal or ethical restrictions

20
Use of Animals in Research

• The Ethical Debate
• The range of opposition
• minimalists-agree that some animal research is
  acceptable, but wish to minimize it
• abolitionists-want all research on animals to stop

21
(No Transcript)
22
Prospects for Further Study

• Researchers Associated with Biological psychology
• Behavioral neuroscience-investigates how the
  function of the brain and other organs influences
  behavior
• Neuroscience-studies anatomy, physiology and
  biochemistry of the nervous system
• Neuropsychologist-conducts behavioral test to
  determine recovery and deterioration after brain
  damage

23
Prospects for Further Study

• Researchers associated with Biological Psychology
  Contd
• Psychophysiologist-measures heart rate, breathing
  rate, brain waves and other body processes that
  change as a function of what someone is doing
• Comparative psychologist-compares the behaviors
  of different species and tries to relate them to
  evolutionary histories and ecological niches
• Sociobiologist-relates behaviors, especially
  social behaviors, to the function they have
  served, and therefore the presumed selective
  pressures that caused them to evolve

24
Prospects for Further Study
Medical Doctors Neurologist-treats people with
brain damage or diseases of the
brain Neurosurgeon-performs brain
surgery Psychiatrist-helps people with emotional
distress or troublesome behaviors, sometimes
using drugs or other medical procedures