Chapter One
The Major Issues
Biological Psychology
“study of the physiological, evolutionary, and developmental
mechanisms of behavior and experience”
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
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
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
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
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
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.
Nature or Nurture
Mendelian Genetics Cont’d
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)
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).
Nature and Nurture
Mendelian Genetics Cont’d
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
Nature and Nurture
Mendelian Genetics Cont’d
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
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
Nature and Nurture Cont’d
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
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.
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
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?
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
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
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
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
Prospects for Further Study
Researchers associated with Biological Psychology Cont’d
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
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