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Chapter 1
Introduction to
Biopsychology
How Biopsychologists
Think about Behavior
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Copyright © 2007 by Allyn and Bacon
Chapter 1 Overview
 What
is Biopsychology?
 Human Evolution
 Fundamental Genetics
 Thinking about the Biology of
Behavior: Mind-Brain and NatureNurture Issues
Copyright © 2007 by Allyn and Bacon
Consider this..
 Does
the brain have
the capacity to
understand something
as complex as itself?
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Four Major Themes

Thinking Clearly about Biopsychology
 Connecting
the text to real life
Clinical Implications
 The Evolutionary Perspective

comparative approach – what can we
learn from other species?
 The

Cognitive Neuroscience
 Connecting
brain activity and cognition
Copyright © 2007 by Allyn and Bacon
What is Biopsychology?
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“the scientific study of the biology of
behavior”
Also known as behavioral neuroscience,
behavioral biology, psychobiology
Psychology: the scientific study of behavior
Hebb (1949) proposed that psychological
phenomena might be produced by brain
activity
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Biopsychology is an integrative
discipline
 Knowledge
from other disciplines of
neuroscience is applied to the study
of behavior
 Each discipline studies a different
aspect of the nervous system that
informs our understanding of what
produces and controls behavior
Copyright © 2007 by Allyn and Bacon
Other Disciplines of Neuroscience
 Neuroanatomy
Structure
of the nervous system
 Neurochemistry
Chemical
bases of neural activity
 Neuroendocrinology
Interactions
between the nervous
system and the endocrine system
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Other Disciplines of Neuroscience
 Neuropathology
Nervous
system disorders
 Neuropharmacology
Effects
of drugs on neural activity
 Neurophysiology
Functions
and activities of the nervous
system
Copyright © 2007 by Allyn and Bacon
Behavior is the Product of
Interactions Among:
 Genes
(“genetic endowment”, nature)
 Experience (nurture)
 Perception of the current situation
 The brain – where these 3 factors
interact
Copyright © 2007 by Allyn and Bacon
Human Evolution
Darwin was not the 1st to
propose that species evolve, he was
the 1st to compile supporting evidence
and to suggest how evolution works
 Darwin presented 3 kinds of evidence
 The most convincing evidence comes
from direct observation of evolution in
progress
 While
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Human Evolution
 Darwin’s
evidence
 Fossil evidence of evolution
 Noted structural similarities among
living
species, suggesting common ancestors
 Impact of selective breeding
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Evolution and Behavior
 Just
as physical features can
contribute to “fitness”, so do
behaviors
 The ability to find food, avoid
predation, etc.
 Social dominance and courtship
displays
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Thinking about Human Evolution
 Evolution
does not proceed in a
single line
 Humans have only been around for a
brief period of time
 Rapid evolutionary changes do occur
 < 1% of all known species are still in
existence
Copyright © 2007 by Allyn and Bacon
Evolution of the Human Brain
 There
is no relationship between
brain size and intelligence
 Brain size is generally correlated with
body size
 More informative to look at relative
size of different brain regions
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Evolution of the Human Brain
 Brain
stem regulates reflex activities
that are critical for survival
 Cerebrum is involved in complex
adaptive processes such as learning,
perception, and motivation
Copyright © 2007 by Allyn and Bacon
Evolution of the Human Brain
 The
human brain has increased in
size during evolution
 Most of the increase in size has
occurred in one region - the cerebrum
 Increased convolutions in the
cerebrum have increased the volume
of the cerebral cortex
Copyright © 2007 by Allyn and Bacon
Evolution of the Human Brain
Copyright © 2007 by Allyn and Bacon
Biopsychological Research Involves
Both Human and Nonhuman Subjects
Why would we look at rats,
mice, and nonhuman
primates to further our
understanding of the human
brain?
 How different are you and a
rat?
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Why use nonhuman subjects?
 While
some questions about behavior
can only be addressed using human
subjects, much can be learned from
studying the brains of other species
 Differences are more quantitative
(relating to size) than qualitative
(relating to function)
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Why use nonhuman subjects?
 Simpler
brains makes it more likely
that brain-behavior interactions will be
revealed
 Comparative approach – gain insight
by making comparisons with other
species
 Fewer ethical restrictions
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Fundamental Genetics
traits – occur in one form
or another, not normally in combination
 True-breeding lines – interbred members
always produce offspring with the same
traits
 Mendel studied dichotomous traits in truebreeding lines of pea plants
 Dichotomous
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Mendel’s Experiments
 Crossed
a line bred true for brown
seeds with one bred true for white
 First generation offspring all had
brown seeds
 When the first generation were bred,
the result was ¾ brown and ¼ white
seeds
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Mendel’s Experiments

True-breeding lines
 White
(ww)
 Brown (BB)
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Brown was the dominant trait, appearing
in all of the 1st generation offspring (Bw)
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Mendel’s Experiments
– observable traits
 Genotype – traits present in the
genes
 If the dominant trait is present in the
genotype (Bw), it will be observed in
the phenotype (brown seeds)
 Phenotype
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Mendel’s Experiments
 Each
inherited factor is a gene
 Two genes that control the same trait
are called alleles
 Homozygous – 2 identical alleles
(BB, ww)
 Heterozygous
– 2 different alleles
(Bw)
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Chromosomes and Reproduction
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Genes are located on
chromosomes in the nucleus of
each cell.
Humans have 23 pairs of
chromosomes, with an allele on
each chromosome
Meiosis – a process of cell division
that yields cells with just 23
chromosomes
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Chromosomes and Reproduction
Gametes, eggs and sperm, are produced
by meiosis
 When egg and sperm combine to form a
fertilized egg (zygote), 23 pairs of
chromosomes are again present
 Mitosis – a form of cell division that yields
daughter cells that have 23 pairs of
chromosomes
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Copyright © 2007 by Allyn and Bacon
Sex Chromosomes and SexLinked Traits
Sex chromosomes, X and Y, look
different and carry different genes
Female = XX, Male = XY
 Sex-linked traits - influenced by genes
on the sex chromosomes
 Dominant traits on the X chromosome
will be seen more commonly in females,
recessive ones in males
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Sex Chromosomes and SexLinked Traits
 Color-blindness
– a recessive sex-
linked trait
 Who is more likely to be color-blind?
 Males
 Why?
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Chromosome Structure and
Replication
 Each
chromosome is a doublestranded molecule of
deoxyribonucleic acid (DNA)
 Each strand consists of a sequence
of nucleotide bases – their
sequence constitutes the genetic
code
Copyright © 2007 by Allyn and Bacon
Copyright © 2007 by Allyn and Bacon
Human Genome Project: What’s
Next?
Why don’t we now have
all the answers?
 How genes interact with
one another and
experience is still not
clear.
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Thinking about the Biology of Behavior:
Mind-Brain and Nature-Nurture Issues
 The
mind-brain issue
Are
the mind and brain one and the
same?
 The
nature-nurture issue
makes you how you are – genes
or environment?
What
 The
genetics of individual differences
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The Mind-Brain Issue
– human brain and mind are
separate
 While we generally accept that mind
and brain are really one today, there
are some who still believe that some
components of the mind are not just
products of brain activity
 Dualism
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Consider this..
 What
evidence
is there that
mind and brain
are one?
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The Nature-Nurture Issue
Is it inherited or is it learned?
 Watson – father of behaviorism – believed
that all behavior was the product of
learning (nurture)
 Ethology – the study of animal behavior in
the wild – focused on instinctive
behaviors, emphasizing nature
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Consider this..
 Is
the “naturenurture” debate
alive today?
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The Nature-Nurture Issue
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Behavior is impacted by factors other than
genetics (nature) or learning (nurture)
“Nurture” now encompasses learning and
environment
While it is generally accepted that behavior is a
product of nature and nurture, many still ask
how much is determined by each
But genetic and experiential factors do not
merely combine in an additive fashion
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The Heritability of Individual
Differences
What conclusions can be made, if any
about the heritability of individual
differences?
 What would a biological psychologist say
about what makes you who and how you
are?
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Copyright © 2007 by Allyn and Bacon