Chapter 1
The Major Issues
The Mind-Brain Relationship
• Biological Psychology is the study of the
physiological, evolutionary and
developmental mechanisms of behavior and
experience.
• A strong emphasis is placed upon brain
functioning.
The Mind-Brain Relationship
• Brain functioning can be explained at a more
microscopic level in terms of neuron and glia
activity.
The Mind-Brain Relationship
• Biological explanations of behavior fall into
four categories:
– Physiological-relates a behavior to the
activity of the brain and other organs.
– Ontogenetic- describes the development of
a structure or behavior.
– Evolutionary- reconstructs evolutionary
history of a behavior or studcutr4.
– Functional- describes why a structure or
behavior evolved as it did.
The Mind-Brain Relationship
• Deep understanding of a particular behavior
is tied to being able to explain the behavior
from each of these perspectives.
The Mind-Brain Relationship
• Biological explanations of behavior raise the
issue of the relationship between the mind
and the brain also know as the “mind-body”
or “mind-brain problem”.
• The “mind-brain problem” has a variety of
explanations.
The Mind-Brain Relationship
• Dualism is the belief that there are different
kinds of substance that exist independently.
– Defended by French philosopher Rene
Descartes.
– Most common belief among nonscientists.
– Rejected by most neuroscientists.
The Mind-Brain Relationship
• Monism is the belief that the universe is only
comprised of one type of substance.
• Forms of monism include:
– Materialism- everything that exists is
physical by nature.
– Mentalism- only the mind truly exists.
– Identity position- mental processes and
some brain processes are the same but
described in different terms.
The Mind-Brain Relationship
• Explanations of the mind-body relationship do
not answer some fundamental questions:
– Why is consciousness a property of brain
activity?
– What kind of brain activity produces
consciousness?
– How does brain activity produce
consciousness?
The Mind-Brain Relationship
• Because “consciousness” is not observable,
its function is often difficult to define and/ or
explain.
• Solipsism- suggests that “I alone am
conscious”
– Difficulty of knowing if others have
conscious experiences is known as the
“problem of other minds”.
The Mind-Brain Relationship
•
Chalmers (1995) proposes two problems
that must be distinguished when discussing
consciousness:
– “Easy problems” focus on differences in
conscious states and their mechanisms.
– “Hard problems” focus on why and how
brain activity is associated with
consciousness.
The Mind-Brain Relationship
•
Careers related to biological psychology fall
into two categories:
1. Research
2. Therapy
The Mind-Brain Relationship
• Insert table 1.1 Fields of specialization
The Genetics of Behavior
• Both genes and environment interact to
shape human behavior.
• The fundamental issue is how much a role
genetics play in shaping human behaviors.
– Examples: psychological disorders, weight
gain, personality, sexual orientation?
The Genetics of Behavior
• 19th century monk Gregor Mendel
demonstrated that inheritance occurs through
genes.
• Genes are basic units of heredity that
maintain their structural identity from one
generation to another.
• Genes are aligned along chromosomes
(strands of genes) and come in pairs.
The Genetics of Behavior
• A gene is a portion of a chromosome and is
composed of deoxyribonucleic acid (DNA).
• DNA serves as a model for the synthesis of
ribonucleic acid (RNA).
The Genetics of Behavior
• RNA is a single strand chemical that can
serve as a template/ model for the synthesis
of proteins.
• Proteins determine the development of the
body by:
• forming part of the structure of the body.
• serving as enzymes, biological catalysts
that regulate chemical reactions in the
body.
The Genetics of Behavior
• Homozygous for a gene means that a person
has an identical pair of genes on the two
chromosomes.
• Heterozygous for a gene means that a
person has an unmatched pair of genes on
the two chromosomes.
The Genetics of Behavior
•
Genes are either dominant, recessive, or
intermediate.
– Examples: eye color, ability to taste PTC
• A dominant gene shows a strong effect in
either the homozygous or heterozygous
condition.
• A recessive gene shows its effect only in
the homozygous condition.
The Genetics of Behavior
• Types of genes include:
– Autosomal genes - all other genes except
for sex- linked genes.
– Sex-linked genes - genes located on the
sex chromosomes.
• In mammals, the sex chromosomes are
designated X & Y.
– Females have two X chromosomes (XX).
– Males have an X and a Y chromosome
(XY).
The Genetics of Behavior
• During reproduction:
– Females contribute an X chromosome.
– Males contribute either an X or a Y
chromosome that determines the sex of
the child.
• If an X chromosome is contributed by the
male, the off-spring is female.
• If a Y chromosome is contributed by the male,
the off-spring will be male.
The Genetics of Behavior
• The human Y chromosome has genes for 27
proteins
• The human X chromosome has genes for
approximately 1500 proteins.
• Thus, sex-linked genes usually refer to Xlinked genes. (Example: Red-green color
deficiency)
• Sex-limited genes are genes that are present
in both sexes but mainly have an effect on
one sex (Chest hair, breast size, etc.)
The Genetics of Behavior
• Almost all behaviors have both a genetic
component and an environmental
component.
• Researchers study monozygotic (“from one
egg”) and fraternal (“from two eggs”) twins to
infer contributions of heredity and
environment
• Researchers also study adopted children and
their resemblance to their biological parents
to infer hereditary influences.
The Genetics of Behavior
• Heritability refers to how much characteristics
depend on genetic differences.
• Estimates of hereditary influences are often
difficult to infer and are prone to error.
• Sources of error include the following:
– The inability to distinguish between the
effects of genes and prenatal influences.
– Environmental factors can inactivate
genes.
The Genetics of Behavior
• Sources of error (con’t)
– Multiplier effect – genetic tendencies that
guide behavior will result in a change in the
environment that magnifies the original
tendency.
– Traits with a strong hereditary influence
can by modified by environmental
intervention.
• Eg. PKU
The Genetics of Behavior
• Genes do not directly produce behaviors.
• Genes produce proteins that increase the
probability that a behavior will develop under
certain circumstances.
• Genes can also have an indirect affect.
– Genes can alter your environment by
producing behaviors or traits that alter how
people in your environment react to you.
The Genetics of Behavior
•
Evolution refers to a change in the
frequency of various genes in a population
over generations
• Regardless if helpful or harmful to the
species.
• Evolution attempts to answer two questions:
1. How did some species evolve?
2. How do species evolve?
The Genetics of Behavior
•
How species did evolve involves the
tentative construction of “evolutionary trees”.
• How species do evolve rests upon some
assumptions:
1. Offspring generally resemble their
parents for genetic reasons.
2. Mutations and recombination of genes
introduce new heritable variations
3. Certain individuals successfully
reproduce more than others do.
The Genetics of Behavior
• Artificial selection refers to choosing
individuals with desired traits and making
them parents of the next generation.
The Genetic of Behavior
• Common misconceptions about evolution
include the following:
– Lamarckian evolution - “The use or disuse
of some structure or behavior causes an
increase or decrease in that behavior.”
– “Humans have stopped evolving.”
– “Evolution means improvement.”
– “Evolution acts to benefit the individual or
the species.”
The Genetics of Behavior
• Evolutionary psychology focuses upon
functional and evolutionary explanations of
how behaviors evolved.
• Assumes that behaviors characteristic of a
species have arisen through natural selection
and provide a survival advantage.
– Examples: differences in peripheral/color
vision, sleep mechanisms in the brain,
eating habits, temperature regulation.
The Genetics of Behavior
• Some behaviors are more debatable
regarding the influence of natural selection.
• Examples include:
– Life span length
– Gender differences in sexual promiscuity
– Altruistic behavior- a behavior that benefits
someone other than the actor
• Explanations: reciprocal altruism & kin
selection
The Use of Animals in Research
• Animal research is an important source of
information for biological psychology but
remains a highly controversial topic.
• Animal research varies on the amount of
stress and/ or pain that is caused to the
animal itself.
The Use of Animals in Research
•
Reasons for studying animals include:
1. The underlying mechanisms of behavior
are similar across species and often
easier to study in nonhuman species.
2. We are interested in animals for their own
sake.
3. What we learn about animals sheds light
on human evolution.
4. Some experiments cannot use humans
because of legal or ethical reasons.
The Use of Animals in Research
• Opposition to animal research varies:
– “Minimalists” favor firm regulation on
research and place consideration upon the
type of animal used and the amount of
stress induced.
– “Abolitionists” maintain that all animals
have the same rights as humans and any
use of animals is unethical.
The Use of Animals in Research
• Justification for research considers the
amount of benefit gained compared to the
amount of distress caused to the animal.
– No clear dividing line exists.
• Colleges and research institutions in the
United States are required to have an
Institutional Animal Care and Use Committee.
– Oversees and determine acceptable
procedures.