Pinel basics ch01

CHAPTER 1INTRODUCTION TO BIOPSYCHOLOGY

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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


CONSIDER THIS..

Does the brain have the capacity to understand something as complex as itself?


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


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


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


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


OTHER DISCIPLINES OF NEUROSCIENCENeuropathology Nervous system disorders

Neuropharmacology Effects of drugs on neural activity

Neurophysiology Functions and activities of the nervous system


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


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


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


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


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


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)


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


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


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



Brain stem regulates reflex activities that are critical for survival

Cerebrum is involved in complex adaptive processes such as learning, perception, and motivation



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




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?


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)


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


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


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



True-breeding linesWhite (ww)Brown (BB)

Brown was the dominant trait, appearing in all of the 1st generation offspring (Bw)



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)



1st generation Bw2nd generation consists of individuals that are BB, Bw, and wwBB, Bw = brownww = white


wwBww

BwBBB

wB


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)


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


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


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


SEX CHROMOSOMES AND SEX-LINKED TRAITSColor-blindness – a recessive sex-linked trait

Who is more likely to be color-blind?

Males

Why?


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


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




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


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.


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


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


CONSIDER THIS..

What evidence is there that mind and brain are one?


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


CONSIDER THIS..

Is the “nature-nurture” debate alive today?


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


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?


Pinel basics ch01

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