CHAPTER 1
THE MAJOR ISSUES
Chapter Outline
I. The Biological Approach to Behavior
A. Two profound and difficult questions:
1. “Why is there something instead of nothing?” There are many more universes that
exist, but string theorists believe that this is the only one that can sustain life.
Factors like gravity, electromagnetism, hydrogen, and water all give this universe
the unique ability to sustain life.
2. The hard problem: Given that this universe composed of matter and energy, why
is there such a thing as consciousness?
3. This question is often called the mind–body or mind–brain problem: What is the
relationship between the mental experience and brain activity?
B. Biological Psychology: The study of the physiological, evolutionary, and
developmental mechanisms of behavior and experience. Much of biological psychology
is devoted to studying how the brain functions. The term biological psychology
emphasizes that the goal of this field is to relate biology to issues of psychology. In
comparison, the field of neuroscience includes much of the same content but with more
emphasis on chemistry and anatomy.
1. Focus on brain function (i.e., how neurons and glia cells work): The activities of
neurons and glia somehow produce an enormous wealth of behavior and
experience. This book will explain what is meant by “somehow.”
C. Biological Explanations of Behavior. They fall into four categories:
1. Physiological explanations: Relate behavior to the activity of the brain and other
organs. Deal with the machinery of the body.
, 2. Ontogenetic explanations: Describe the development of a structure or a behavior.
Look at the influence of genes, nutrition, experience, and the interaction among
these influences on behavior.
3. Evolutionary explanations: Examine a structure or a behavior in terms of
evolutionary history. Examine the continuity (unbroken course) of a behavior from
past ancestors to the present.
4. Functional explanations: Describe why a structure or behavior evolved as it did.
Look for the benefit or advantage for having certain behaviors.
D. Career Opportunities
1. Careers in biological psychology fall into two categories: research and therapy
2. Research positions require a Ph.D. in psychology, biology, neuroscience, or related
field and may be in academic, government, or industrial settings.
3. Fields of therapy include clinical psychology, counseling psychology, school
psychology, several specializations of medicine, and allied medical practice, such
as physical therapy.
II. Genetics and Behavior
A. Mendelian Genetics
1. During the nineteenth century, Gregor Mendel demonstrated that inheritance occurs
through genes (units of heredity that maintain their identity from one generation to
the next).
2. As a rule, genes come in pairs, as they are aligned along chromosomes (strands of
genes). One exception to this rule is male sex chromosomes, which do not come in
pairs.
3. A gene is a portion of a chromosome, which is composed of a double-stranded
chemical called deoxyribonucleic acid (DNA).
4. A strand of DNA serves as a template (model) for the synthesis of ribonucleic acid
(RNA).
5. RNA is a single-stranded chemical: One type of RNA serves as a template for the
synthesis of protein molecules.
, 6. Proteins can be part of the structure of the body or serve as enzymes (biological
catalysts that regulate chemical reactions in the body).
7. If individuals have an identical pair of genes on the two chromosomes, they are
homozygous for that gene; if they instead have an unmatched pair of genes, they
are heterozygous for that gene (e.g., a gene for black hair on one chromosome and
a gene for brown hair on the other).
8. Certain genes can be identified as dominant or recessive.
Dominant genes show a strong effect in either homozygous or heterozygous
conditions; recessive genes show their effects only in homozygous conditions
(e.g., a carrier for both a dominant black hair gene and a recessive brown hair
gene will have black hair).
9. Nuances in gene expression:
Often, more than one single gene contributes to the appearance of certain
characteristics (e.g., 10 genes contribute to variations in eye color).
Partial expression of a gene is also possible.
B. Sex-Linked and Sex-Limited Genes
1. Genes located on sex chromosomes are known as sex-linked genes. All other
chromosomes are referred to as autosomal chromosomes. Genes located on
autosomal chromosomes are autosomal genes.
2. A female mammal has two X chromosomes; a male has one X and one Y
chromosome.
3. The Y chromosome carries the gene that causes a person to develop as a male; the
X chromosome carries many genes (these are usually referred to as sex-linked
genes).
4. Sex-linked recessive genes have their effects only in the absence of the dominant
gene.
5. Sex-limited genes: Genes present in both sexes but mainly or exclusively have
effects in one sex. The differential effect is found because these genes must be
activated by sex hormones.
C. Genetic Changes
1. Genes change in several ways.
, 2. Mutation: a heritable change in a DNA molecule. Changing one base in DNA to
any of the other three types means that the mutant gene will code for a protein with
a different amino acid at one location in the molecule.
a) Mutations are rarely advantageous. One rare example: FOXP2 gene, which
facilitates language development.
b) Other types of mutations: duplication or deletion; microduplication or
microdeletion. Scientist believe microduplications and microdeletions may
be responsible for schizophrenia.
3. Epigenetics: changes in gene expression without modification of the DNA
sequence (e.g., brain changes resulting from drug addiction).
a) How experience can modify gene expression: The result of an experience—
maternal deprivation, cocaine exposure, new learning, or whatever—brings
new proteins into a cell or in other ways alters the chemical environment.
Experiences alter the activity of genes.
D. Heredity and Environment
1. Most variations in behavior depend on the combined influence of many genes and
environmental influences.
2. Heritability is an estimate of how much of the variance in some characteristic is due
to heredity.
3. Heritability in humans is studied in three ways: by comparing monozygotic
(identical) twins, dizygotic (fraternal) twins, and adopted children and their
biological parents.
4. Environmental influences may affect traits with high heritability (e.g.,
Phenylketonuria, or PKU: A genetically caused form of mental retardation that
can be avoided with a strict diet that prevents build up of phenylalanine).
5. Genes affect behavior through the proteins they produce and their influence on
specific body systems.
D. Evolution of Behavior
1. Evolution: Change over generations in the frequencies of various genes in a
population.
2. Offspring generally resemble their parents, but because of mutations and
recombinations, new inheritable variations in the gene pool can occur.
THE MAJOR ISSUES
Chapter Outline
I. The Biological Approach to Behavior
A. Two profound and difficult questions:
1. “Why is there something instead of nothing?” There are many more universes that
exist, but string theorists believe that this is the only one that can sustain life.
Factors like gravity, electromagnetism, hydrogen, and water all give this universe
the unique ability to sustain life.
2. The hard problem: Given that this universe composed of matter and energy, why
is there such a thing as consciousness?
3. This question is often called the mind–body or mind–brain problem: What is the
relationship between the mental experience and brain activity?
B. Biological Psychology: The study of the physiological, evolutionary, and
developmental mechanisms of behavior and experience. Much of biological psychology
is devoted to studying how the brain functions. The term biological psychology
emphasizes that the goal of this field is to relate biology to issues of psychology. In
comparison, the field of neuroscience includes much of the same content but with more
emphasis on chemistry and anatomy.
1. Focus on brain function (i.e., how neurons and glia cells work): The activities of
neurons and glia somehow produce an enormous wealth of behavior and
experience. This book will explain what is meant by “somehow.”
C. Biological Explanations of Behavior. They fall into four categories:
1. Physiological explanations: Relate behavior to the activity of the brain and other
organs. Deal with the machinery of the body.
, 2. Ontogenetic explanations: Describe the development of a structure or a behavior.
Look at the influence of genes, nutrition, experience, and the interaction among
these influences on behavior.
3. Evolutionary explanations: Examine a structure or a behavior in terms of
evolutionary history. Examine the continuity (unbroken course) of a behavior from
past ancestors to the present.
4. Functional explanations: Describe why a structure or behavior evolved as it did.
Look for the benefit or advantage for having certain behaviors.
D. Career Opportunities
1. Careers in biological psychology fall into two categories: research and therapy
2. Research positions require a Ph.D. in psychology, biology, neuroscience, or related
field and may be in academic, government, or industrial settings.
3. Fields of therapy include clinical psychology, counseling psychology, school
psychology, several specializations of medicine, and allied medical practice, such
as physical therapy.
II. Genetics and Behavior
A. Mendelian Genetics
1. During the nineteenth century, Gregor Mendel demonstrated that inheritance occurs
through genes (units of heredity that maintain their identity from one generation to
the next).
2. As a rule, genes come in pairs, as they are aligned along chromosomes (strands of
genes). One exception to this rule is male sex chromosomes, which do not come in
pairs.
3. A gene is a portion of a chromosome, which is composed of a double-stranded
chemical called deoxyribonucleic acid (DNA).
4. A strand of DNA serves as a template (model) for the synthesis of ribonucleic acid
(RNA).
5. RNA is a single-stranded chemical: One type of RNA serves as a template for the
synthesis of protein molecules.
, 6. Proteins can be part of the structure of the body or serve as enzymes (biological
catalysts that regulate chemical reactions in the body).
7. If individuals have an identical pair of genes on the two chromosomes, they are
homozygous for that gene; if they instead have an unmatched pair of genes, they
are heterozygous for that gene (e.g., a gene for black hair on one chromosome and
a gene for brown hair on the other).
8. Certain genes can be identified as dominant or recessive.
Dominant genes show a strong effect in either homozygous or heterozygous
conditions; recessive genes show their effects only in homozygous conditions
(e.g., a carrier for both a dominant black hair gene and a recessive brown hair
gene will have black hair).
9. Nuances in gene expression:
Often, more than one single gene contributes to the appearance of certain
characteristics (e.g., 10 genes contribute to variations in eye color).
Partial expression of a gene is also possible.
B. Sex-Linked and Sex-Limited Genes
1. Genes located on sex chromosomes are known as sex-linked genes. All other
chromosomes are referred to as autosomal chromosomes. Genes located on
autosomal chromosomes are autosomal genes.
2. A female mammal has two X chromosomes; a male has one X and one Y
chromosome.
3. The Y chromosome carries the gene that causes a person to develop as a male; the
X chromosome carries many genes (these are usually referred to as sex-linked
genes).
4. Sex-linked recessive genes have their effects only in the absence of the dominant
gene.
5. Sex-limited genes: Genes present in both sexes but mainly or exclusively have
effects in one sex. The differential effect is found because these genes must be
activated by sex hormones.
C. Genetic Changes
1. Genes change in several ways.
, 2. Mutation: a heritable change in a DNA molecule. Changing one base in DNA to
any of the other three types means that the mutant gene will code for a protein with
a different amino acid at one location in the molecule.
a) Mutations are rarely advantageous. One rare example: FOXP2 gene, which
facilitates language development.
b) Other types of mutations: duplication or deletion; microduplication or
microdeletion. Scientist believe microduplications and microdeletions may
be responsible for schizophrenia.
3. Epigenetics: changes in gene expression without modification of the DNA
sequence (e.g., brain changes resulting from drug addiction).
a) How experience can modify gene expression: The result of an experience—
maternal deprivation, cocaine exposure, new learning, or whatever—brings
new proteins into a cell or in other ways alters the chemical environment.
Experiences alter the activity of genes.
D. Heredity and Environment
1. Most variations in behavior depend on the combined influence of many genes and
environmental influences.
2. Heritability is an estimate of how much of the variance in some characteristic is due
to heredity.
3. Heritability in humans is studied in three ways: by comparing monozygotic
(identical) twins, dizygotic (fraternal) twins, and adopted children and their
biological parents.
4. Environmental influences may affect traits with high heritability (e.g.,
Phenylketonuria, or PKU: A genetically caused form of mental retardation that
can be avoided with a strict diet that prevents build up of phenylalanine).
5. Genes affect behavior through the proteins they produce and their influence on
specific body systems.
D. Evolution of Behavior
1. Evolution: Change over generations in the frequencies of various genes in a
population.
2. Offspring generally resemble their parents, but because of mutations and
recombinations, new inheritable variations in the gene pool can occur.
