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CHAPTER 1INTRODUCTION TO BIOPSYCHOLOGY
HOW B
IOPS
YCHOLO
GISTS
THIN
K ABOUT
BEHAVIO
R
COPYRIGHT © 2007 BY ALLYN AND BACON
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CHAPTER 1 OVERVIEW
What is Biopsychology?
Human Evolution
Fundamental Genetics
Thinking about the Biology of Behavior: Mind-Brain and Nature-Nurture Issues
COPYRIGHT © 2007 BY ALLYN AND BACON
CONSIDER THIS..
Does the brain have the capacity to understand something as complex as itself?
COPYRIGHT © 2007 BY ALLYN AND BACON
FOUR MAJOR THEMES
Thinking Clearly about Biopsychology
Connecting the text to real lifeClinical ImplicationsThe Evolutionary PerspectiveThe comparative approach – what can we learn from other species?
Cognitive NeuroscienceConnecting brain activity and cognition
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WHAT IS BIOPSYCHOLOGY?
“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
COPYRIGHT © 2007 BY ALLYN AND BACON
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
COPYRIGHT © 2007 BY ALLYN AND BACON
OTHER DISCIPLINES OF NEUROSCIENCENeuropathology Nervous system disorders
Neuropharmacology Effects of drugs on neural activity
Neurophysiology Functions and activities of the nervous system
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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 While 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
COPYRIGHT © 2007 BY ALLYN AND BACON
HUMAN EVOLUTION
Darwin’s evidence Fossil evidence of evolution Noted structural similarities among living species,
suggesting common ancestors Impact of selective breedingDirect observation of evolution in progress Grant (1991) – finches of the Galapagos islands changed
dramatically after a single season of drought
COPYRIGHT © 2007 BY ALLYN AND BACON
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
COPYRIGHT © 2007 BY ALLYN AND BACON
THINKING ABOUT HUMAN EVOLUTIONEvolution 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
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THINKING ABOUT HUMAN EVOLUTIONEvolution is a tinkerer, not an architect – results are not perfect
Not all existing behaviors or structures are adaptive Spandrels – incidental non-adaptive by-products (such as the human
belly button)
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THINKING ABOUT HUMAN EVOLUTIONNot all existing adaptive
characteristics evolved to perform their current function
Exaptions – evolved to do one thing, but now do something else (such as bird wings)
Similarities among species do not necessarily mean that the species have common origins
COPYRIGHT © 2007 BY ALLYN AND BACON
THINKING ABOUT HUMAN EVOLUTIONHomologous structures – similar
structures due to a common evolutionary origin
Analogous structures – similar structures without a common origin
Convergent evolution – the evolution of similar solutions to the same enivironmental demands by unrelated species
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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
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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
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EVOLUTION OF THE HUMAN BRAIN
COPYRIGHT © 2007 BY ALLYN AND BACON
BIOPSYCHOLOGICAL RESEARCH INVOLVES BOTH HUMAN AND NONHUMAN SUBJECTSWhy 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
Dichotomous traits – occur in one form or another, not normally in combinationTrue-breeding lines – interbred members always produce offspring with the same traitsMendel studied dichotomous traits in true-breeding lines of pea plants
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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 linesWhite (ww)Brown (BB)
Brown was the dominant trait, appearing in all of the 1st generation offspring (Bw)
COPYRIGHT © 2007 BY ALLYN AND BACON
MENDEL’S EXPERIMENTS
Phenotype – 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)
COPYRIGHT © 2007 BY ALLYN AND BACON
MENDEL’S EXPERIMENTS
1st generation Bw2nd generation consists of individuals that are BB, Bw, and wwBB, Bw = brownww = white
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wwBww
BwBBB
wB
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)
COPYRIGHT © 2007 BY ALLYN AND BACON
CHROMOSOMES AND REPRODUCTIONGenes 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
COPYRIGHT © 2007 BY ALLYN AND BACON
CHROMOSOMES AND REPRODUCTIONGametes, 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
COPYRIGHT © 2007 BY ALLYN AND BACON
SEX CHROMOSOMES AND SEX-LINKED TRAITS
Sex chromosomes, X and Y, look different and carry different genesFemale = XX, Male = XY
Sex-linked traits - influenced by genes on the sex chromosomesDominant traits on the X chromosome will be seen more commonly in females, recessive ones in males
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SEX CHROMOSOMES AND SEX-LINKED TRAITSColor-blindness – a recessive sex-linked trait
Who is more likely to be color-blind?
Males
Why?
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CHROMOSOME STRUCTURE AND REPLICATIONEach chromosome is a double-stranded molecule of
deoxyribonucleic acid (DNA)
Each strand consists of a sequence of nucleotide bases – their sequence constitutes the genetic code
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CHROMOSOME STRUCTURE AND REPLICATIONReplication of each strand must occur prior to mitosis
Errors may occur
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
COPYRIGHT © 2007 BY ALLYN AND BACON
THE GENETIC CODE AND GENE EXPRESSIONStructural genes – code for synthesis of proteins
Operator genes – control a structural gene or a group of structural genes
Operator genes control gene expression
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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.
COPYRIGHT © 2007 BY ALLYN AND BACON
THINKING ABOUT THE BIOLOGY OF BEHAVIOR: MIND-BRAIN AND NATURE-NURTURE ISSUESThe mind-brain issue Are the mind and brain one and the same?
The nature-nurture issue What makes you how you are – genes or environment?
The genetics of individual differences
COPYRIGHT © 2007 BY ALLYN AND BACON
THE MIND-BRAIN ISSUE
Dualism – 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
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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 “nature-nurture” debate alive today?
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THE NATURE-NURTURE ISSUE
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?
COPYRIGHT © 2007 BY ALLYN AND BACON